Final California 2010 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 7 - Colorado River Basin Region

Water Body Name: Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
Water Body ID: CAR7151000020080709112211
Water Body Type: River & Stream
 
DECISION ID
8832
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1, 1-dichloroethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8832, 1, 1-dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17116
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1,1,2-Tetrachloroethane | 1,1-Dichloropropene | 1,2,3-Trichloropropane | 1,2-Dibromo-3-chloropropane | 1,3-Dichloropropane | 2,2-Dichloropropane | Bromochloromethane | Chloroform | Ethylene dibromide | Methylene bromide (Dibromomethane)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, and 1,1-Dichloropropene consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17116, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29489
 
Pollutant: 1,1,1,2-Tetrachloroethane | 1,1-Dichloropropene | 1,2,3-Trichloropropane | 1,2-Dibromo-3-chloropropane | 1,3-Dichloropropane | 2,2-Dichloropropane | Bromochloromethane | Chloroform | Ethylene dibromide | Methylene bromide (Dibromomethane)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8845
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1,1-Trichloroethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8845, 1,1,1-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8855
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1,2,2-Tetrachloroethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the drinking water MCL. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8855, 1,1,2,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7669
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,2-Dichloroethane | Benzene | Carbon tetrachloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8820
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1,2-Trichloroethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8820, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8820, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8820, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8833
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8833, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17134
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2,3-Trichlorobenzene | Chloroethane | Dichlorodifluoromethane | Methyl chloride (Chloromethane) | cis-1,3-Dichloropropene | trans-1,3-Dichloropropene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Methyl Chloride, Chloroethane, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, and 1,2,3-Trichlorobenzene consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Methyl Chloride, Chloroethane, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Methyl Chloride, Chloroethane, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17134, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29810
 
Pollutant: 1,2,3-Trichlorobenzene | Chloroethane | Dichlorodifluoromethane | Methyl chloride (Chloromethane) | cis-1,3-Dichloropropene | trans-1,3-Dichloropropene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Methyl Chloride, Chloroethane, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002 from the six locations.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8844
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2,4-Trichlorobenzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8844, 1,2,4-Trichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17114
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2,4-Trimethylbenzene | 1,3,5-Trimethylbenzene | Bromobenzene | Cumene | delta-BHC (Benzenehexachloride or delta-HCH) | n-Butylbenzene | n-Propylbenzene | sec-Butylbenzene | tert-Butylbenzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 135-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, and tert-Butylbenzene consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 135-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, or tert-Butylbenzene or the sediment fraction of delta-BHC for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 135-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, or tert-Butylbenzene or the sediment fraction of delta-BHC for the protection of human, animal or aquatic life in fresh waters that meets the requirements of section 6.1.3 of the Listing Policy could be found.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17114, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29486
 
Pollutant: 1,2,4-Trimethylbenzene | 1,3,5-Trimethylbenzene | Bromobenzene | Cumene | delta-BHC (Benzenehexachloride or delta-HCH) | n-Butylbenzene | n-Propylbenzene | sec-Butylbenzene | tert-Butylbenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 135-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, or tert-Butylbenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17114, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29544
 
Pollutant: delta-BHC (Benzenehexachloride or delta-HCH)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Nine sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guideline for the sediment fraction of delta-BHC for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Nine sediment samples were collected. Sediment samples were collected and analyzed in May of 2002, November of 2003, and May of 2004 from the Imperial Dam grate location. The rest of the locations were sampled in May of 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8800
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2-Dichloroethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded either the drinking water MCL or the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8800, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7669
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,2-Dichloroethane | Benzene | Carbon tetrachloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8800, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8800, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8803
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2-Dichloroethylene,-trans
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8803, 1,2-Dichloroethylene,-trans
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8801
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2-Dichloropropane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8801, 1,2-Dichloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8801, 1,2-Dichloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8801, 1,2-Dichloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17119
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1-Methylnaphthalene | 2,3,5-Trimethylnaphthalene | 2,6-Dimethylnaphthalene | 2-Methylnaphthalene | Acenaphthylene | Naphthalene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Acenaphthylene, Naphthalene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, and 2,3,5-Trimethylnaphthalene consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Acenaphthylene, Naphthalene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene or the sediment fractions of Acenaphthylene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Acenaphthylene, Naphthalene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene or the sediment fraxctions of Acenaphthylene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17119, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29492
 
Pollutant: 1-Methylnaphthalene | 2,3,5-Trimethylnaphthalene | 2,6-Dimethylnaphthalene | 2-Methylnaphthalene | Acenaphthylene | Naphthalene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Acenaphthylene, Naphthalene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17119, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29547
 
Pollutant: 1-Methylnaphthalene | 2,3,5-Trimethylnaphthalene | 2,6-Dimethylnaphthalene | 2-Methylnaphthalene | Acenaphthylene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Acenaphthylene, 1-Methylnaphthalene, 2-Methynaphthalene, 2,6-Dimethylnaphthalene, or 2,3,5-Trimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17118
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1-Methylphenanthrene | Phenanthrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Phenanthrene, and 1-Methylphenanthrene consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Phenanthrene, or 1-Methylphenanthrene or the sediment fraction of 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Phenanthrene, or 1-Methylphenanthrene or the sediment fraction of 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17118, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29491
 
Pollutant: 1-Methylphenanthrene | Phenanthrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Phenanthrene, or 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17118, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29546
 
Pollutant: 1-Methylphenanthrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guideline for the sediment fraction of 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17115
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 2-Chlorotoluene | 4-Chlorotoluene | p-Cymene (p-Isopropyltoluene)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess 2-Chlorotoluene, 4-Chlorotoluene, and p-Cymene consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, or p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17115, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29487
 
Pollutant: 2-Chlorotoluene | 4-Chlorotoluene | p-Cymene (p-Isopropyltoluene)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, or p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17135
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 2-Hexanone | Acetone | Methyl ethyl ketone (2-Butanone) | Methyl isobutyl ketone (Methyl-2-Pentanone)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, and 2-Hexanone consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17135, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29507
 
Pollutant: 2-Hexanone | Acetone | Methyl ethyl ketone (2-Butanone) | Methyl isobutyl ketone (Methyl-2-Pentanone)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002 from the six locations.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8783
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Acenaphthene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8783, Acenaphthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8783, Acenaphthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17145
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Acenaphthene | Aldrin | Chlorpyrifos | Diazinon | Toxaphene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Acenaphthene, Aldrin, Chlorpyrifos, Diazinon, and Toxaphene consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Acenaphthene, Aldrin, Chlorpyrifos, Diazinon, or Toxaphene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Acenaphthene, Aldrin, Chlorpyrifos, Diazinon, or Toxaphene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17145, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29596
 
Pollutant: Acenaphthene | Aldrin | Chlorpyrifos | Diazinon | Toxaphene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of alpha-HCH, beta-HCH, Hexachlorobenzene, or Methoxychlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8822
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Aldrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8822, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8827
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Aluminum
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the primary drinking water MCL, or secondary MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8827, Aluminum
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8827, Aluminum
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17143
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Aluminum | Manganese | Silver
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Aluminum, Manganese, and Silver consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Aluminum, Manganese, or Silver for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Aluminum, Manganese, or Silver for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17143, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29594
 
Pollutant: Aluminum | Manganese | Silver
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Aluminum, Manganese, or Silver for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17128
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Ametryn | Prometryn | Simetryn | Terbutryn
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Ametryn, Prometryn, Simetryn, and Terbutryn consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17128, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29501
 
Pollutant: Ametryn | Prometryn | Simetryn | Terbutryn
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fourteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fourteen water samples were collected. Water samples were generally collected and analyzed from 5/2002 through 5/2004 from the Imperial Dam grate location. No samples were collected in 2003 from this location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8789
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Anthracene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8789, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8789, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17139
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Anthracene | Benzo(a)anthracene | Dibenz[a,h]anthracene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Anthracene, Benz(a)Anthracene, and Dibenzo(a,h)Anthracene consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Anthracene, Benz(a)Anthracene, or Dibenzo(a,h)Anthracene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Anthracene, Benz(a)Anthracene, or Dibenzo(a,h)Anthracene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17139, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29579
 
Pollutant: Anthracene | Benzo(a)anthracene | Dibenz[a,h]anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Anthracene, Benz(a)Anthracene, or Dibenzo(a,h)Anthracene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8823
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Arsenic
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the Califonia Toxics Rule criteria or the drinking water MCL. None of 17 water samples exceeded the U.S. Fish and Wildlife Service criteria. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8823, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7685
 
Pollutant: Arsenic | Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the USFWS Biological Effect Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: United State Fish and Wildlife Service (USFWS) Biological Effect Criteria for the protection of aquatic life uses were used for the following constituents: 0.25 mg/l Arsenic, and 15 mg/l Copper (USFWS, 1998).
Guideline Reference: Guidelines for Interpretation of the Biological Effect of Selected Constituents in Biota, Water, and Sediment. US Department of Interior report.
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8823, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8823, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8823, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8852
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Atrazine
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 16 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8852, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7672
 
Pollutant: Atrazine | Simazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Sixteen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Atrazine, and 0.004 mg/l Simazine (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Sixteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. No samples were collected from the Imperial Dame grate location in 2003. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):
 
 
DECISION ID
17129
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Atroton | Prometon (Prometone) | Secbumeton
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Atroton, Prometon, and Secbumeton consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17129, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29502
 
Pollutant: Atroton | Prometon (Prometone) | Secbumeton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fourteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fourteen water samples were collected. Water samples were generally collected and analyzed from 5/2002 through 5/2004 from the Imperial Dam grate location. No samples were collected in 2003 from this location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17122
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Azinphos, Ethyl (Ethyl Guthion) | Azinphos-methyl (Guthion)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Azinphos, methyl, and Azinphos, ethyl consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Azinphos, methyl, or Azinphos, ethyl for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Azinphos, methyl, or Azinphos, ethyl for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17122, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29495
 
Pollutant: Azinphos, Ethyl (Ethyl Guthion) | Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Azinphos, methyl, or Azinphos, ethyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8792
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8792, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8792, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8790
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo(a)anthracene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the CTR criteria, and none of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8790, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8790, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8815
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo(a)pyrene (3,4-Benzopyrene -7-d)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL.None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8815, Benzo(a)pyrene (3,4-Benzopyrene -7-d)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8815, Benzo(a)pyrene (3,4-Benzopyrene -7-d)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7623
 
Pollutant: Benzo(a)pyrene (3,4-Benzopyrene -7-d)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentration (PEC) of 1450 ug/kg for the protection of freshwater organisms to toxic effects (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17127
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo(e)Pyrene (4,5-benzopyrene) | Benzo[g,h,i]perylene | Biphenyl | Terbufos
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, and Terbufos consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos or the sediment fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, or Biphenyl for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos or the sediment fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, or Biphenyl for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17127, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29576
 
Pollutant: Benzo(e)Pyrene (4,5-benzopyrene) | Benzo[g,h,i]perylene | Biphenyl
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, or Biphenyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17127, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29500
 
Pollutant: Benzo(e)Pyrene (4,5-benzopyrene) | Benzo[g,h,i]perylene | Biphenyl | Terbufos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8809
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo[b]fluoranthene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8809, Benzo[b]fluoranthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17140
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo[b]fluoranthene | Benzo[k]fluoranthene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Benzo(b)Fluoranthene, and Benzo(k)Fluoranthene consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Benzo(b)Fluoranthene, or Benzo(k)Fluoranthene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Benzo(b)Fluoranthene, or Benzo(k)Fluoranthene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17140, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29580
 
Pollutant: Benzo[b]fluoranthene | Benzo[k]fluoranthene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Benzo(b)Fluoranthene, or Benzo(k)Fluoranthene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8810
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Benzo[k]fluoranthene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8810, Benzo[k]fluoranthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17125
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Bolstar | Chlordane | Ciodrin | Dacthal | Demeton s | Dichlorvos | Dimethoate | Disulfoton | Endrin Ketone | Ethoprop | Famphur | Mirex | Naled | Oxadiazon
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, and Oxadiazon consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon or the sediment fractions of Dacthal, Mirex, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon or the sediment fractions of Dacthal, Mirex, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17125, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29809
 
Pollutant: Bolstar | Chlordane | Ciodrin | Dacthal | Demeton s | Dichlorvos | Dimethoate | Disulfoton | Endrin Ketone | Ethoprop | Famphur | Mirex | Naled | Oxadiazon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17125, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29574
 
Pollutant: Dacthal | Mirex | Oxadiazon
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Dacthal, Mirex, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8793
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Bromoform
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8793, Bromoform
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8793, Bromoform
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8829
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Cadmium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the drinking water MCL or the Basin Plan water quality objective. None of 15 water samples exceeded the California Toxics Rule criteria. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8829, Cadmium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7631
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Hardness Dependant Criterion Maximum Concentration (CMC) for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8829, Cadmium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8829, Cadmium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7693
 
Pollutant: Cadmium | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Methoxychlor | Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8829, Cadmium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17147
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Carbon (organic)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess organic Carbon consistent with Listing Policy section 3.6.

No evaluation guideline for the sediment fraction of organic carbon for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guideline for the sediment fraction of organic Carbon for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17147, Carbon (organic)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29598
 
Pollutant: Carbon (organic)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guideline for the sediment fraction of Organic Carbon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8854
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Carbon tetrachloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 11 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8854, Carbon tetrachloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7669
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,2-Dichloroethane | Benzene | Carbon tetrachloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8854, Carbon tetrachloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8854, Carbon tetrachloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17120
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Carbophenothion | Dichlofenthion | Dioxathion | Ethion | Fenitrothion | Fensulfothion | Fenthion | Malathion | Methidathion | Methyl Parathion | Parathion | Tokuthion
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, and Tokuthion consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion or the sediment fractions of Parathion, or Methyl Parathion for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion or the sediment fractions of Parathion, or Methyl Parathion for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17120, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29572
 
Pollutant: Methyl Parathion | Parathion
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Parathion, or Methyl Parathion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17120, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29493
 
Pollutant: Carbophenothion | Dichlofenthion | Dioxathion | Ethion | Fenitrothion | Fensulfothion | Fenthion | Malathion | Methidathion | Methyl Parathion | Parathion | Tokuthion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8824
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chlordane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8824, Chlordane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8824, Chlordane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17123
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chlorfenvinphos | Chlorpyrifos, methyl | Cuomaphos | Dicrotophos | Dyfonate (Fonofos or Fonophos) | Fenchlorphos | Leptophos | Merphos | Mevinphos | Tetrachlorvinphos
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, and Chlorpyrifos Methyl consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos Methyl could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos Methyl for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17123, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29496
 
Pollutant: Chlorfenvinphos | Chlorpyrifos, methyl | Cuomaphos | Dicrotophos | Dyfonate (Fonofos or Fonophos) | Fenchlorphos | Leptophos | Merphos | Mevinphos | Tetrachlorvinphos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8847
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water secondary MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8847, Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8795
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chlorobenzene (mono)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8795, Chlorobenzene (mono)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8795, Chlorobenzene (mono)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8795, Chlorobenzene (mono)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8825
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chromium (total)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8825, Chromium (total)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8825, Chromium (total)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8856
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Chrysene (C1-C4)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8856, Chrysene (C1-C4)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8848
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Copper
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting either aquatic life uses or human health when consuming water and organisms from these waters. None of 17 water samples exceeded either the U.S. Fish and Wildlife Service criteria or the drinking water secondary MCL. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8848, Copper
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7685
 
Pollutant: Arsenic | Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the USFWS Biological Effect Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: United State Fish and Wildlife Service (USFWS) Biological Effect Criteria for the protection of aquatic life uses were used for the following constituents: 0.25 mg/l Arsenic, and 15 mg/l Copper (USFWS, 1998).
Guideline Reference: Guidelines for Interpretation of the Biological Effect of Selected Constituents in Biota, Water, and Sediment. US Department of Interior report.
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8848, Copper
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8848, Copper
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8848, Copper
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8848, Copper
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7618
 
Pollutant: Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule Hardness Dependent Criterion Maximum Concentration (CMC) for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8874
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8874, DDT (Dichlorodiphenyltrichloroethane)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7643
 
Pollutant: DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentration (CMC) for pp'-DDT of 1.1 ug/l for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8858
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Diazinon
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Department of Fish and Game criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8858, Diazinon
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7690
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDFG Hazardous Assessment Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Fish and Games (CDFG) Hazardous Assessment Criteria of 0.16 ug/l for the protection of aquatic life uses (Siepmann and Finlayson, 2000).
Guideline Reference: Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8791
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dibenz[a,h]anthracene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8791, Dibenz[a,h]anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17133
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dibenzothiophene | o-Xylene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Dibenzothiophene, and o-Xylene consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Dibenzothiophene, or o-Xylene or the sediment fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Dibenzothiophene, or o-Xylene or the sediment fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17133, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29578
 
Pollutant: Dibenzothiophene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guideline for the sediment fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17133, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29506
 
Pollutant: Dibenzothiophene | o-Xylene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Nine water samples were generally collected biannually from 10/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guideline for the dissolved fractions of Dibenzothiophene, or o-Xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Nine water samples were collected. Water samples were generally collected and analyzed from 10/2002 through 5/2004 from the upstream of the Imperial Dam, and at the Imperial Dam Grates locations. Samples were usually collected in May and October. Samples were not collected in 5/2003 from the Imperial Dam grates, samples were not collected from upstream of the Imperial Dam in 11/2003 and 5/2004. The rest of the locations were only sampled in 10/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17146
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dichlorobenzophenone | Indeno[1,2,3-cd]pyrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Indeno(1,2,3,c,d)Pyrene, and pp-DCBPconsistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Indeno(1,2,3,c,d)Pyrene, or pp-DCBP for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Indeno(1,2,3,c,d)Pyrene, or pp-DCBP for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17146, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29597
 
Pollutant: Dichlorobenzophenone | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Indeno(1,2,3,c,d)Pyrene, or Dichlorobenzophenone (pp-DCBP) for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8799
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dichlorobromomethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8799, Dichlorobromomethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8799, Dichlorobromomethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8859
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dichloromethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 6 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8859, Dichloromethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27213
 
Pollutant: Dichloromethane | Methyl bromide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8859, Dichloromethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7646
 
Pollutant: Dichloromethane | Methyl bromide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8864
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Dieldrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8864, Dieldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8864, Dieldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8788
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Endosulfan sulfate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms only from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8788, Endosulfan sulfate
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8788, Endosulfan sulfate
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17141
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Endosulfan sulfate | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Endosulfan 1, Endosulfan 2, and Endosulfan Sulfate consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Endosulfan 1, Endosulfan 2, or Endosulfan Sulfate for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Endosulfan 1, Endosulfan 2, or Endosulfan Sulfate for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17141, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29581
 
Pollutant: Endosulfan sulfate | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Endosulfan 1, Endosulfan 2, or Endosulfan Sulfate for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8804
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Endrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded either the drinking water MCL or the California Toxics Rule criteria protecting aquatic life uses. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8804, Endrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8804, Endrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8804, Endrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8804, Endrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8804, Endrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8805
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Endrin aldehyde
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8805, Endrin aldehyde
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8805, Endrin aldehyde
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8862
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Enterococcus
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Two of the samples in each line of evidence exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Two of 15 water samples exceeded the Basin Plan Enterococcus water quality objective that protects RECI beneficial uses, and two of 15 water samples exceeded the Basin plan Enterococcus water quality objective that protects RECII beneficial uses. These do not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8862, Enterococcus
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7609
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, 2 exceeded the Basin Plan Objective (SWAMP, 2007). The exceedance were found in samples collected on 10/02/2002 at Taylor Lake, and 11/04/2003 at the Imperial Dam grates (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 61 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 10/2004 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003 The exceedances were found in samples collected from 10/02/2002 through 11/04/2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
Line of Evidence (LOE) for Decision ID 8862, Enterococcus
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7612
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, 2 exceeded the Basin Plan Objective. The exceedance were found in samples collected on 10/02/2002 at Taylor Lake, and 11/04/2003 at the Imperial Dam grates (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 305 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 10/2004 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003 The exceedances were found in samples collected from 10/02/2002 through 11/04/2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8863
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Escherichia coli (E. coli)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 15 water samples exceeded the Basin Plan E. coli water quality objectives that protect RECI and RECII beneficial usues. These do not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8863, Escherichia coli (E. coli)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7704
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan:In the Colorado River the maximum allowable E. coli density is 1175 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 10/2004 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8863, Escherichia coli (E. coli)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7701
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan:In the Colorado River the maximum allowable E. coli density is 235 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 10/2004 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8806
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Ethylbenzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8806, Ethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8806, Ethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8806, Ethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8807
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Fluoranthene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8807, Fluoranthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8807, Fluoranthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8807, Fluoranthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8808
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Fluorene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8808, Fluorene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8808, Fluorene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8808, Fluorene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8826
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Heptachlor
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8826, Heptachlor
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8826, Heptachlor
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8828
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Heptachlor epoxide
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8828, Heptachlor epoxide
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8828, Heptachlor epoxide
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17142
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Heptachlor | Heptachlor epoxide
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Heptachlor, and Heptachlor Epoxide consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of Heptachlor, or Heptachlor Epoxide for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of Heptachlor, or Heptachlor Epoxide for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17142, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29582
 
Pollutant: Heptachlor | Heptachlor epoxide
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of Heptachlor, or Heptachlor Epoxide for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8834
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Hexachlorobenzene/ HCB
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8834, Hexachlorobenzene/ HCB
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17144
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Hexachlorobenzene/ HCB | Methoxychlor | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess alpha-HCH, beta-HCH, Hexachlorobenzene, and Methoxychlor consistent with Listing Policy section 3.6.

No evaluation guidelines for the sediment fractions of alpha-HCH, beta-HCH, Hexachlorobenzene, or Methoxychlor for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the sediment fractions of alpha-HCH, beta-HCH, Hexachlorobenzene, or Methoxychlor for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17144, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29595
 
Pollutant: Hexachlorobenzene/ HCB | Methoxychlor | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of alpha-HCH, beta-HCH, Hexachlorobenzene, or Methoxychlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8811
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Hexachlorobutadiene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these water. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8811, Hexachlorobutadiene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8811, Hexachlorobutadiene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17136
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Hydroxide
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Hydroxide consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fraction of Hydroxide for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fraction of Hydroxide for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17136, Hydroxide
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29508
 
Pollutant: Hydroxide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guideline for Hydroxide for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002 from the six locations.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8816
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Indeno[1,2,3-cd]pyrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 11 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8816, Indeno[1,2,3-cd]pyrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7662
 
Pollutant: 1,1,2,2-Tetrachloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | Benzo(a)anthracene | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Benzo[b]fluoranthene | Benzo[k]fluoranthene | Carbon tetrachloride | Chrysene (C1-C4) | Dibenz[a,h]anthracene | Indeno[1,2,3-cd]pyrene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: Benzene, 0.049 ug/l Benzo[a]Anthracene, 0.049 ug/l Benzo[a]Pyrene, 0.049 Benzo[b]Fluoranthene, 0.049 ug/l Benzo[k]Fluoranthene, 4.4 ug/l Carbon Tetrachloride, 0.049 ug/l Chrysene, 0.049 ug/l Dibenzo(a,h)Anthracene, 3.2 ug/l 1,1-Dichloroethylene, 0.049 ug/l Indeno(1,2,3-cd) Pyrene, and 11 ug/l 1,1,2,2-Tetrachloroethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8857
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Lead
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the Basin Plan water quality objective to protect the MUN beneficial use, or the California Toxics Rule criteria. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8857, Lead
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7693
 
Pollutant: Cadmium | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Methoxychlor | Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8857, Lead
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7637
 
Pollutant: Lead | Nickel | Silver | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8835
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the drinking water MCL or the Basin Plan water quality objective. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8835, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8835, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8835, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7693
 
Pollutant: Cadmium | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Methoxychlor | Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8849
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Manganese
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water secondary MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8849, Manganese
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8812
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Mercury
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the National Recommended Water Quality Criteria protecting aquatic life use or the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8812, Mercury
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8812, Mercury
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8812, Mercury
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8812, Mercury
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8812, Mercury
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7640
 
Pollutant: Mercury
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the NRWQC criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: National Recommended Water Quality Criteria (NRWQC) Criterion Maximum Concentration (CMC) of 1.4 ug/l for the protection of freshwater aquatic life uses (USEPA, 2002).
Objective/Criterion Reference: National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8836
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Methoxychlor
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the drinking water MCL or the Basin Plan water quality objective to protect the MUN beneficial use. None of 17 water samples exceeded the USEPA drinking water criteria. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8836, Methoxychlor
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7628
 
Pollutant: Methoxychlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the USEPA criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: USEPA Drinking Water Criteria of 40 ug/l for the protection of drinking water uses (USEPA, 2002).
Guideline Reference: National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8836, Methoxychlor
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7693
 
Pollutant: Cadmium | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Methoxychlor | Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8836, Methoxychlor
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8837
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Methyl Tertiary-Butyl Ether (MTBE)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the primary drinking water MCL or secondary MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8837, Methyl Tertiary-Butyl Ether (MTBE)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8837, Methyl Tertiary-Butyl Ether (MTBE)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8860
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Methyl bromide
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 6 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8860, Methyl bromide
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27213
 
Pollutant: Dichloromethane | Methyl bromide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8860, Methyl bromide
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7646
 
Pollutant: Dichloromethane | Methyl bromide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8838
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Molinate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8838, Molinate
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8865
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Naphthalene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 sediment samples exceeded the sediment quality guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8865, Naphthalene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8813
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Nickel
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting either aquatic life uses or human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8813, Nickel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8813, Nickel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8813, Nickel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8813, Nickel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8813, Nickel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7637
 
Pollutant: Lead | Nickel | Silver | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8839
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Nitrate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8839, Nitrate
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8840
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Nitrogen, Nitrite
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8840, Nitrogen, Nitrite
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17126
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Oxychlordane | Perylene (Dibenz(de,kl)anthracene) | Phorate | Phosmet | Phosphamidon | Sulfotep | Tedion | Thionazin | Trichlorfon | Trichloronate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, and Trichlorfon consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon or the sediment fractions of Oxychlordane, Perylene, or Tedion for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon or the sediment fractions of Oxychlordane, Perylene, or Tedion for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17126, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29499
 
Pollutant: Oxychlordane | Perylene (Dibenz(de,kl)anthracene) | Phorate | Phosmet | Phosphamidon | Sulfotep | Tedion | Thionazin | Trichlorfon | Trichloronate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17126, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29575
 
Pollutant: Oxychlordane | Perylene (Dibenz(de,kl)anthracene) | Tedion
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8841
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: PCBs (Polychlorinated biphenyls)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8841, PCBs (Polychlorinated biphenyls)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8841, PCBs (Polychlorinated biphenyls)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8782
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Perchlorate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Two water samples exceeded the water quality objective. When compared to the drinking water 6 ug/l threshold for human health, there were 2 exceedances in October 2002 out of 17 total water samples taken over all the sampling years. However, not enough samples were collected and reported to develop an accurate assessment of perchlorate in the Colorado River.

A remedial effort has been underway since October 2002 to remove perchlorate from a source near Henderson, NV. Because of this, monitoring data collected before October 2002 are no longer representative of perchlorate in the River.

A recent report on the progress of remedial efforts reported that the concentration of perchlorate in this segment of the Colorado River (monitoring location at the diversion to the California Aquaeduct) is decreasing. Monitoring data collected since October 2002 indicates generally declining concentrations of perchlorate (USEPA, 2006; SWAMP, 2007). In 2005 at the Colorado River diversion to the California Aqueduct, twelve monthly samples reported perchlorate concentrations below 4 ppb (USEPA, 2006).

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Two out of 17 water samples exceeded the drinking water MCL used to interpret the water quality objective in October 2002 and this exceeds the allowable frequency calculated from the equation in Table 3.1 of the Listing Policy. However, not enough samples were collected and reported to develop an accurate assessment of perchlorate in the Colorado River.
4. Monitoring data collected since October 2002 by the SWAMP program and other indicates generally declining concentrations of perchlorate. In 2005 at the Colorado River diversion to the California Aqueduct, twelve monthly samples collected by others reported perchlorate concentrations below 4 ppb
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is insufficient information was collected and reported to accurately assess perchlorate in the Colorado River.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8782, Perchlorate
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7615
 
Pollutant: Perchlorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, 2 exceeded the CDPH MCL (SWAMP, 2007). The exceedences were found in samples collected on 10/01/2002 at Taylor Lake, and 10/02/02 at Parker Dam (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Level (MCL) of 0.006 mg/l for the protection of human health (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003 The exceedances were found in samples collected from 10/01/2002 through 10/02/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8866
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Phenanthrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 sediment samples exceeded the sediment quality guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8866, Phenanthrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17137
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Pheophytin a
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.7.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Pheophytin a consistent with Listing Policy section 3.7.1.

No evaluation guideline for the dissolved fraction of Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guideline for the dissolved fraction of Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17137, Pheophytin a
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29509
 
Pollutant: Pheophytin a
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guideline for Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002 from the six locations.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17130
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Propazine | Terbuthylazine
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Propazine, and Terbuthylazine consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of Propazine, or Terbuthylazine for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of Propazine, or Terbuthylazine for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17130, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29503
 
Pollutant: Propazine | Terbuthylazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fourteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of Propazine, or Terbuthylazine for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fourteen water samples were collected. Water samples were generally collected and analyzed from 5/2002 through 5/2004 from the Imperial Dam grate location. No samples were collected in 2003 from this location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8814
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Pyrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8814, Pyrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8814, Pyrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7696
 
Pollutant: Arsenic | Benzo(a)anthracene | Cadmium | Chromium (total) | Chrysene (C1-C4) | Copper | Dieldrin | Endrin | Fluoranthene | Fluorene | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Naphthalene | Nickel | PCBs (Polychlorinated biphenyls) | Phenanthrene | Pyrene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentrations (PECs) for the protection of freshwater organisms to toxic effects were used for the following constituents: 33 mg/kg Arsenic, 1050 ug/kg Benz[a]anthrazene, 4.98 mg/kg Cadmium, 111 mg/kg Chromium, 1290 ug/kg Chrysene, 149 mg/kg Copper, 61.8 ug/g Dieldrin, 207 ug/kg Endrin, 2230 ug/kg Fluoranthene, 536 ug/kg Fluorene, 128 mg/kg Lead, 4.99 ug/kg Lindane/Hexachlorocyclohexane (HCH), 1.06 mg/kg Mercury, 561 ug/kg Naphthalene, 48.6 mg/kg Nickel, 1170 ug/kg Phenanthrene, 676 ug/kg PCBs (Polychlorinated biphenyls), and 1520 ug/kg Pyrene (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8814, Pyrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17138
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Salinity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess Salinity consistent with Listing Policy section 3.2.

No evaluation guideline for Salinity for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guideline for Salinity for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17138, Salinity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29510
 
Pollutant: Salinity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Three water samples were collected from 4/2003 through 4/2004 at 2 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guideline for Salinity for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Three water samples were collected. Water samples were collected from 4/2003 through 4/2004 upstream of the Imperial Dam, and 11/2003, and 5/2004 from the Imperial Dam Grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8842
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Selenium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

There were a total of fifteen sediment samples collected. However, no evaluation guideline for the fraction of selenium associated with sediment could be found that protects human, animal or aquatic life in fresh waters and meets the requirements of section 6.1.3 of the Listing Policy. Because of this, Line of Evidence No. 30277 received a Use Rating of Insufficient Information.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8842, Selenium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8842, Selenium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 30277
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guideline for the sediment fraction of Selenium for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8850
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Silver
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the Basin Plan water quality objective to protect the MUN beneficial use. None of 17 water samples exceeded the drinking water secondary MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8850, Silver
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7693
 
Pollutant: Cadmium | Lead | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Methoxychlor | Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8850, Silver
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7637
 
Pollutant: Lead | Nickel | Silver | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8850, Silver
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8853
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Simazine
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 16 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8853, Simazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7672
 
Pollutant: Atrazine | Simazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Sixteen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Atrazine, and 0.004 mg/l Simazine (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Sixteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. No samples were collected from the Imperial Dame grate location in 2003. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):
 
 
DECISION ID
8876
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Specific Conductance
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water secondary MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8876, Specific Conductance
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7682
 
Pollutant: Specific Conductance
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen measurements were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total measurements, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Level (SMCL) of 1600 umhos for consumer acceptance (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Measurements were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water quality measurements were collected. Water quality measurements were generally collected biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Measurements were usually collected in May and October. The rest of the locations were measured in May and October 2002. An extra measurement was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17132
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Streptococcus, fecal
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess fecal Streptococcus consistent with Listing Policy section 3.3.

No evaluation guidelines for the total density of fecal Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the total density of fecal Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17132, Streptococcus, fecal
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29505
 
Pollutant: Streptococcus, fecal
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 14
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fourteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guideline for Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fourteen water samples were collected. Water samples were generally collected and analyzed from 5/2002 through 5/2004 from the Imperial Dam grate location. No samples were collected in 2003 from this location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8877
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Styrene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 6 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8877, Styrene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7656
 
Pollutant: Styrene | Trichlorofluoromethane (CFC-11)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.1 mg/l Styrene, and 0.15 mg/l Trichlorofluoromethane (CFC-11) (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8818
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Tetrachloroethylene/PCE
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8818, Tetrachloroethylene/PCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8818, Tetrachloroethylene/PCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8818, Tetrachloroethylene/PCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8843
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Thiobencarb/Bolero
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the primary drinking water MCl, or secondary MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8843, Thiobencarb/Bolero
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8843, Thiobencarb/Bolero
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8819
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Toluene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8819, Toluene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8819, Toluene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8819, Toluene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17131
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Total Petroleum Hydrocarbons as Diesel
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess Total Petroleum Hydrocarbons as Diesel used to refer to the dissolved fractions of Diesel Range Organics consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved or sediment fractions of Total Petroeum Hydrocarbons as Diesel for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved and sediment fractions of Total Petroleum Hydrocarbons as Diesel for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17131, Total Petroleum Hydrocarbons as Diesel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29577
 
Pollutant: Total Petroleum Hydrocarbons as Diesel
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fourteen sediment samples were generally collected from 5/2002 through 11/2003 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines forthe sediment fractions Total Petroleum Hydrocarbons as Diesel, used to refer to the dissolved fractions of Diesel Range Organics (dro), for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fourteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17131, Total Petroleum Hydrocarbons as Diesel
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29504
 
Pollutant: Total Petroleum Hydrocarbons as Diesel
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 13
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Thirteen water samples were generally collected biannually from 5/2002 through 4/2003 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for Total Petroleum Hydrocarbons as Diesel, used to refer to the dissolved fractions of Diesel Range Organics (dro), for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Thirteen water samples were collected. Water samples were generally collected and analyzed from May of 2002 through May of 2003 from the upstream of the Imperial Dam location. Samples were collected in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8821
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Trichloroethylene/TCE
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water exceeded the drinking water MCL. None of 11 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8821, Trichloroethylene/TCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27212
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8821, Trichloroethylene/TCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8821, Trichloroethylene/TCE
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7649
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Dichlorobromomethane | Hexachlorobutadiene | Tetrachloroethylene/PCE | Trichloroethylene/TCE
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen samples were taken at 6 locations along this segment of the Colorado River. Six water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The 11 acceptable water quality sample were collected from 10/2002 through 5/2005 at 6 locations. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8878
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Trichlorofluoromethane (CFC-11)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 6 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8878, Trichlorofluoromethane (CFC-11)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7656
 
Pollutant: Styrene | Trichlorofluoromethane (CFC-11)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.1 mg/l Styrene, and 0.15 mg/l Trichlorofluoromethane (CFC-11) (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8879
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Turbidity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Two of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Two of 17 water samples exceeded the drinking water secondary MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8879, Turbidity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7606
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water quality measurements were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total measurements, two exceeded the CDPH SMCL . The exceedances were found in measurements collected on 4/09/2003 upstream of Imperial Dam, and 5/10/2005 at Imperial Dam grates (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Level (SMCL) of 5 NTU for consumer acceptance (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Measurements were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water quality measurements were collected. Water quality measurements were generally collected biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Measurements were usually collected in May and October. The rest of the locations were measured in May and October 2002. An extra measurement was collected from the upstream of Imperial Dam location inn April 2003 The exceedances were found in measurements collected from 4/09/2003 through 5/10/2005.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8861
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Vinyl chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 6 water samples exceeded the California Toxics Rule criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8861, Vinyl chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7659
 
Pollutant: Dichloromethane | Methyl bromide | Vinyl chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Six water samples were collected in 5/2002 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming organisms from aquatic systems were used for the following constituents: 4000 ug/l Methyl Bromide, 1600 ug/l Dichloromethane, and 525 ug/l Vinyl Chloride (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Six water samples were collected. Water samples were collected in 5/2002.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8846
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Xylenes (total) (mixed)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8846, Xylenes (total) (mixed)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8851
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Zinc
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded either the California Toxics Rule criteria or the drinking water MCL. None of 17 sediment samples exceeded the sediment quality guideline. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8851, Zinc
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7625
 
Pollutant: Zinc
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen sediment samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the PEC (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Consensus Based Sediment Quality Guideline Probable Effects Concentration (PEC) of 459 mg/kg for the protection of freshwater organisms to toxic effects (Macdonald et al, 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8851, Zinc
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7679
 
Pollutant: Aluminum | Chloride | Copper | Manganese | Methyl Tertiary-Butyl Ether (MTBE) | Silver | Sulfates | Thiobencarb/Bolero | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8851, Zinc
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7637
 
Pollutant: Lead | Nickel | Silver | Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17121
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: alpha-Chlordene | gama-Chlordene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess alpha-Chlordene, and gamma-Chlordene consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved fractions of alpha-Chlordene, or gamma-Chlordene or the sediment fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of alpha-Chlordene, or gamma-Chlordene or the sediment fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17121, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29573
 
Pollutant: alpha-Chlordene | gama-Chlordene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).


No evaluation guidelines for the sediment fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17121, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29494
 
Pollutant: alpha-Chlordene | gama-Chlordene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8786
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: alpha-Endosulfan (Endosulfan 1)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting either aquatic life uses or protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8786, alpha-Endosulfan (Endosulfan 1)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8786, alpha-Endosulfan (Endosulfan 1)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8786, alpha-Endosulfan (Endosulfan 1)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8784
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: alpha.-BHC (Benzenehexachloride or alpha-HCH)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8784, alpha.-BHC (Benzenehexachloride or alpha-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8784, alpha.-BHC (Benzenehexachloride or alpha-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8785
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: beta-BHC (Benzenehexachloride or beta-HCH)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8785, beta-BHC (Benzenehexachloride or beta-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8785, beta-BHC (Benzenehexachloride or beta-HCH)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8787
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: beta-Endosulfan (Endosulfan 2)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting either aquatic life use or protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8787, beta-Endosulfan (Endosulfan 2)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7634
 
Pollutant: Aldrin | Arsenic | Chlordane | Chromium (total) | Dieldrin | Endrin | Heptachlor | Heptachlor epoxide | alpha-Endosulfan (Endosulfan 1) | beta-Endosulfan (Endosulfan 2)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location inn April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8787, beta-Endosulfan (Endosulfan 2)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8787, beta-Endosulfan (Endosulfan 2)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8802
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: cis-1,2-Dichloroethylene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the drinking water MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8802, cis-1,2-Dichloroethylene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17117
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: cis-Nonachlor | trans-Nonachlor
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under sections 3.1 and 3.6 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess alpha-Nonachlor, and trans-Nonachlor consistent with Listing Policy sections 3.1 and 3.6.

No evaluation guidelines for the dissolved or sediment fractions of cis-Nonachlor, or trans-Nonachlor could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved or sediment fractions of cis-Nonachlor, or trans-Nonachlor for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17117, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29490
 
Pollutant: cis-Nonachlor | trans-Nonachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of cis-Nonachlor, or trans-Nonachlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 17117, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29545
 
Pollutant: cis-Nonachlor | trans-Nonachlor
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen sediment samples were generally collected from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).

No evaluation guidelines for the sediment fractions of cis-Nonachlor, or trans-Nonachlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen sediment samples were collected. Sediment samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October from the Imperial Dam grate location. No sample was collected from the Imperial Dam grate location in April of 2003. The rest of the locations were sampled in May and October of 2002. An extra sample was collected from the upstream of Imperial Dam location in April of 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8797
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: m-Dichlorobenzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8797, m-Dichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8797, m-Dichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
17124
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: o,p'-DDD (Dichlorodiphenyldichloroethane)) | o,p'-DDE (Dichlorodiphenyldichloroethylene) | o,p'-DDT (Dichlorodiphenyltrichloroethane) | p,p'-DDMU
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess o,p'-DDD, o,p'-DDE, o,p'-DDT, and p,p'-DDMU consistent with Listing Policy section 3.1.

No evaluation guidelines for the dissolved fractions of o,p'-DDD, o,p'-DDE, o,p'-DDT, or p,p'-DDMU for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. No evaluation guidelines for the dissolved fractions of o,p'-DDD, o,p'-DDE, o,p'-DDT, or p,p'-DDMU for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 17124, Multiple Pollutants
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 29497
 
Pollutant: o,p'-DDD (Dichlorodiphenyldichloroethane)) | o,p'-DDE (Dichlorodiphenyldichloroethylene) | o,p'-DDT (Dichlorodiphenyltrichloroethane) | p,p'-DDMU
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances:
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Fifteen water samples were generally collected biannually from 5/2002 through 5/2004 at 6 locations along this segment of the Colorado River (SWAMP, 2006).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).

No evaluation guidelines for the dissolved fractions of o,p'-DDD, o,p'-DDE, o,p'-DDT, or p,p'-DDMU for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Fifteen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8796
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: o-Dichlorobenzene
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8796, o-Dichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8796, o-Dichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8796, o-Dichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8798
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: p-Dichlorobenzene (DCB)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters. None of 17 water samples exceeded the drinking water MCL. These do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8798, p-Dichlorobenzene (DCB)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7652
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8798, p-Dichlorobenzene (DCB)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 27211
 
Pollutant: Acenaphthene | Anthracene | Chlorobenzene (mono) | Endosulfan sulfate | Endrin | Endrin aldehyde | Ethylbenzene | Fluoranthene | Fluorene | Mercury | Nickel | Pyrene | Toluene | alpha-Endosulfan (Endosulfan 1) | alpha.-BHC (Benzenehexachloride or alpha-HCH) | beta-BHC (Benzenehexachloride or beta-HCH) | beta-Endosulfan (Endosulfan 2) | m-Dichlorobenzene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate locations. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
Line of Evidence (LOE) for Decision ID 8798, p-Dichlorobenzene (DCB)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7674
 
Pollutant: 1, 1-dichloroethane | 1,1,1-Trichloroethane | 1,1,2-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride | 1,2,4-Trichlorobenzene | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Aluminum | Arsenic | Benzo(a)pyrene (3,4-Benzopyrene -7-d) | Cadmium | Chlordane | Chlorobenzene (mono) | Chromium (total) | Endrin | Ethylbenzene | Heptachlor | Heptachlor epoxide | Hexachlorobenzene/ HCB | Lindane/gamma Hexachlorocyclohexane (gamma-HCH) | Mercury | Methoxychlor | Methyl Tertiary-Butyl Ether (MTBE) | Molinate | Nickel | Nitrate | Nitrogen, Nitrite | PCBs (Polychlorinated biphenyls) | Selenium | Tetrachloroethylene/PCE | Thiobencarb/Bolero | Toluene | Trichloroethylene/TCE | Xylenes (total) (mixed) | cis-1,2-Dichloroethylene | o-Dichlorobenzene | p-Dichlorobenzene (DCB)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water samples were generally collected biannually from 5/2002 through 5/2005 at 6 locations along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Spatial Representation: Samples were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Samples were usually collected in May and October. The rest of the locations were sampled in May and October 2002. An extra sample was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
 
DECISION ID
8875
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of 9 water samples exceeded the Basin Plan water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 8875, pH
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 7708
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Seventeen water quality measurements were taken at 6 locations along this segment of the Colorado River. Eight measurements could not be used in this assessment because of equipment failure or lack of proper documentation. The 9 acceptable measurements were collected from 5/2002 through 5/2005 at 1 location. Of these total measurements, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference: Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0 (CRBRWQCB, 2006).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Measurements were collected from the following Colorado River locations: downstream of Parker Dam, from three small associated lakes on the River (Ferguson, Taylor and Squaw), upstream of Imperial Dam, and at the Imperial Dam grates.
Temporal Representation: Seventeen water quality measurements were collected. Water quality measurements were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Imperial Dam grate location. Measurements were usually collected in May and October. The rest of the locations were measured in May and October 2002. An extra measurement was collected from the upstream of Imperial Dam location in April 2003.
Environmental Conditions:
QAPP Information: The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)