Final California 2018 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
77980
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Toxicity
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2025
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the section 303(d) list under section 4.6 of the Listing Policy. Under section 4.6 a single line of evidence is necessary to assess listing status.

Six lines of evidence are available in the administrative record to assess this pollutant. Six 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 removing this water segment-pollutant combination from 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. Five of 13 water samples and one of seven sediment samples exhibit toxicity when compared to control samples. This exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 31973
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Eight samples were collected to evaluate water toxicity. Two of the samples exhibited significant toxicity to Ceriodaphnia dubia reproduction. The toxicity test included survival and reproduction of Ceriodaphnia dubia and survial and biomass of Pimephales promelas. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 7 Basin Plan.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold.
Guideline Reference: Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
 
Spatial Representation: The samples were collected at station 715CRIDG1.
Temporal Representation: The samples were collected in April 2008, October 2005, 2007 and 2008 and May 2007 and 2006.
Environmental Conditions:
QAPP Information: Data quality is good. Data results were recorded in the SWAMP database and follwed SWAMP protocols.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125394
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 3 of the 5 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia, for Young/female, Ceriodaphnia dubia, for Survival
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 stations. Monitoring site(s): ( 715CRIDG1, 715CRIDU1 )
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19.
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125389
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 3 of the 5 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia, for Young/female, Ceriodaphnia dubia, for Survival
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 stations. Monitoring site(s): ( 715CRIDG1, 715CRIDU1 )
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19.
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125406
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 1 of the 3 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca, for Survival, Hyalella azteca, for Growth (wt/surv indiv)
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 stations. Monitoring site(s): ( 715CRIDG1 )
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11.
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 31974
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Four samples were collected to evaluate sediment toxicity. None of the samples exhibited significant toxicity. The toxicity test included survival and growth of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 7 Basin Plan.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold.
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at station 715CRIDG1.
Temporal Representation: The samples were collected in April 2008 and May and October 2007.
Environmental Conditions:
QAPP Information: Data quality is good. Data results were recorded in the SWAMP database and follwed SWAMP protocols.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 77980, Toxicity
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125396
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 1 of the 3 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca, for Survival, Hyalella azteca, for Growth (wt/surv indiv)
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 stations. Monitoring site(s): ( 715CRIDG1 )
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11.
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70958
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: Do Not List on 303(d) list (TMDL required list)(2016)
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 dissolved fraction and none of six total fraction water samples exceeded the California 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.
 
 
Line of Evidence (LOE) for Decision ID 70958, 1, 1-dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34759
 
Pollutant: 1, 1-dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1-Dichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 1-Dichloroethane is 5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70958, 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)
 
Line of Evidence (LOE) for Decision ID 70958, 1, 1-dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128867
 
Pollutant: 1, 1-dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Dichloroethane, 1,1-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 1-Dichloroethane is 0.005 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
78586
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1, 2-Dibromoethane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
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(s) of evidence are 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(s).

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. Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy. This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 78586, 1, 2-Dibromoethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127964
 
Pollutant: 1, 2-Dibromoethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dibromoethane, 1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 2-Dibromoethane is 0.00005 mg/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78586, 1, 2-Dibromoethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34729
 
Pollutant: 1, 2-Dibromoethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 2-Dibromoethane is 0.05 ug/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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
104159
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,1,1,2-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.

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.

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. Zero of 15 dissolved fraction water samples collected 2002-2005 exceeded the objective as no evaluation guideline 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.

Four total fraction samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

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.
 
 
Line of Evidence (LOE) for Decision ID 104159, 1,1,1,2-Tetrachloroethane
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)
 
Line of Evidence (LOE) for Decision ID 104159, 1,1,1,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128510
 
Pollutant: 1,1,1,2-Tetrachloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Tetrachloroethane, 1,1,1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The USEPA Health Advisory for Tetrachloroethane, 1,1,1,2- as a drinking water level with a one in a million cancer risk is 0.001 mg/L.
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
71584
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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 six total fraction and none of 17 dissolved fraction water samples exceeded the California 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.
 
 
Line of Evidence (LOE) for Decision ID 71584, 1,1,1-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34724
 
Pollutant: 1,1,1-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1, 1-Trichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 1, 1-Trichloroethane is 200 ug/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 71584, 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)
 
Line of Evidence (LOE) for Decision ID 71584, 1,1,1-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128469
 
Pollutant: 1,1,1-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trichloroethane, 1,1,1-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 1, 1-Trichloroethane is 0.2 mg/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70901
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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 11 water samples exceeded the California MCL.
None of six water samples exceeded the California Toxics Rule Criteria.
This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
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.
 
 
Line of Evidence (LOE) for Decision ID 70901, 1,1,2,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127929
 
Pollutant: 1,1,2,2-Tetrachloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Tetrachloroethane, 1,1,2,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2, 2-Tetrachloroethane criteria for the protection of human health from the consumption of water and organisms is 0.17 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70901, 1,1,2,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35670
 
Pollutant: 1,1,2,2-Tetrachloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2, 2-Tetrachloroethane criteria for the protection of human health from the consumption of water and organisms is 0.17 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70901, 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)
 
Line of Evidence (LOE) for Decision ID 70901, 1,1,2,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126979
 
Pollutant: 1,1,2,2-Tetrachloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Tetrachloroethane, 1,1,2,2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2, 2-Tetrachloroethane criteria for the protection of human health from consumption of organisms only is 11 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70901, 1,1,2,2-Tetrachloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35649
 
Pollutant: 1,1,2,2-Tetrachloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Tetrachloroethane, 1,1,2,2-.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2, 2-Tetrachloroethane criteria for the protection of human health from consumption of organisms only is 11 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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
70944
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

Eight lines of evidence are available in the administrative record to assess this pollutant. LOEs No. 27212 and 7649 are replaced by the LOEs No. 46761 and 7674, respectively, because LOE No. 27212 and 7649 were reassessed using updated criteria. None of samples exceed the water quality objectives.

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 dissolved fraction and none of two total fraction water samples exceeded the CTR criteria for the "Municipal & Domestic Supply " beneficial use assessed. Four samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

None of 17 dissolved fraction and none of six total fraction water samples exceeded the CTR criteria for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed.

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.
 
 
Line of Evidence (LOE) for Decision ID 70944, 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 70944, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 46761
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | 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: 17
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. 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 only from aquatic systems were used for the following constituents: 71 ug/l Benzene, 360 ug/l Bromoform, 46 ug/l Dichlorobromomethane, 99 ug/l 1,2-Dichloroethane, 39 ug/l 1,2-Dichloropropane, 50 ug/l Hexachlorobutadiene, 8.85 ug/l Tetrachloroehtylene, 42 ug/l 1,1,2-Trichloroethane, and 81 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 70944, 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 70944, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127692
 
Pollutant: 1,1,2-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trichloroethane, 1,1,2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2-Trichloroethane criteria for the protection of human health from consumption of organisms only is 42 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70944, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34741
 
Pollutant: 1,1,2-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1, 2-Trichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2-Trichloroethane criteria for the protection of human health from consumption of organisms only is 42 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70944, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127942
 
Pollutant: 1,1,2-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Trichloroethane, 1,1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2-Trichloroethane criteria for the protection of human health from the consumption of water and organisms is 0.60 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70944, 1,1,2-Trichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34757
 
Pollutant: 1,1,2-Trichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1, 2-Trichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1, 2-Trichloroethane criteria for the protection of human health from the consumption of water and organisms is 0.60 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70944, 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
70961
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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

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 dissolved fraction water samples exceeded the California MCL. Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

None of six total fraction water samples exceeded the California Toxics Tule Criteria.

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.
 
 
Line of Evidence (LOE) for Decision ID 70961, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34792
 
Pollutant: 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1-Dichloroethylene criteria for the protection of human health from the consumption of water and organisms is 0.057ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70961, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128904
 
Pollutant: 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichloroethylene, 1,1-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1-Dichloroethylene criteria for the protection of human health from the consumption of water and organisms is 0.057ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70961, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128873
 
Pollutant: 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Dichloroethylene, 1,1-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1-Dichloroethylene criteria for the protection of human health from consumption of organisms only is 3.2 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70961, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34776
 
Pollutant: 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1-Dichloroethylene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 1-Dichloroethylene criteria for the protection of human health from consumption of organisms only is 3.2 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70961, 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
104202
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2,3-Trichloropropane
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 objectives.

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 dissolved fraction water samples collected 2002-2004 exceeded the objective as no evaluation guidelines for the dissolved fraction 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.

Zero of zero samples collected in 2013 exceeded the California Maximum Contaminant Levels. The four samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104202, 1,2,3-Trichloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127064
 
Pollutant: 1,2,3-Trichloropropane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Trichloropropane, 1,2,3-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Basin Plan's \Chemical Constituents\" objective. The CA Primary MCL for Trichloropropane, 1,2,3- is 0.000005 ug/L"
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104202, 1,2,3-Trichloropropane
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
79866
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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 dissolved fraction and none of six total fraction water samples exceeded the California 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.
 
 
Line of Evidence (LOE) for Decision ID 79866, 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)
 
Line of Evidence (LOE) for Decision ID 79866, 1,2,4-Trichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34809
 
Pollutant: 1,2,4-Trichlorobenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2, 4-Trichlorobenzene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: The National Recommended Water Quality Criteria for 1,2,4-Trichlorobenzene is 70 ug/l for water and fish consumption.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 79866, 1,2,4-Trichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127209
 
Pollutant: 1,2,4-Trichlorobenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Trichlorobenzene, 1,2,4-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The National Recommended Water Quality Criteria for 1,2,4-Trichlorobenzene is 0.076 ug/l for water and fish consumption.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79866, 1,2,4-Trichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127689
 
Pollutant: 1,2,4-Trichlorobenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trichlorobenzene, 1,2,4-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1,2,4-Trichlorobenzene is 0.005 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79866, 1,2,4-Trichlorobenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34813
 
Pollutant: 1,2,4-Trichlorobenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2, 4-Trichlorobenzene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1,2,4-Trichlorobenzene is 5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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
104203
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2,4-Trimethylbenzene
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 this section 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 objectives.

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. Zero of 15 dissolved fraction water samples collected 2002-2005 exceeded the objective as no evaluation guidelines for the dissolved fraction 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.

Zero of four total fraction water samples exceeded the California Department of Public Health (CDPH) notification level.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104203, 1,2,4-Trimethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128486
 
Pollutant: 1,2,4-Trimethylbenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trimethylbenzene, 1,2,4-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Deparment of Public Health (CDPH) notification level for 1,2,4-Trimethylbenzene is 330 ug/L.
Guideline Reference: Drinking Water Notification Levels and Response Levels
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104203, 1,2,4-Trimethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128487
 
Pollutant: 1,2,4-Trimethylbenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trimethylbenzene, 1,2,4-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Deparment of Public Health (CDPH) notification level for 1,2,4-Trimethylbenzene is 330 ug/L.
Guideline Reference: Drinking Water Notification Levels and Response Levels
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104203, 1,2,4-Trimethylbenzene
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)
 
 
DECISION ID
104207
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,2-Dibromo-3-chloropropane
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.

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

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. Zero of 15 dissolved fraction water samples collected 2002-2004 exceeded the objective as no evaluation guideline 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.

Zero of zero total fraction water samples exceeded the California Maximum Contaminant Level. The six samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5. LOE 127538 replaces LOE 127537 because they are duplicates.

None of two water samples exceeded the California MCL for chloroform and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104207, 1,2-Dibromo-3-chloropropane
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)
 
Line of Evidence (LOE) for Decision ID 104207, 1,2-Dibromo-3-chloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127537
 
Pollutant: 1,2-Dibromo-3-chloropropane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dibromo-3-Chloropropane, 1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 2-Dibromo-3-Chloropropane (DBCP) is 0.20 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104207, 1,2-Dibromo-3-chloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127538
 
Pollutant: 1,2-Dibromo-3-chloropropane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dibromo-3-Chloropropane, 1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 2-Dibromo-3-Chloropropane(DBCP) is 0.0002 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104207, 1,2-Dibromo-3-chloropropane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34727
 
Pollutant: 1,2-Dibromo-3-chloropropane (DBCP)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for 1, 2-Dibromo-3-Chloropropane(DBCP) is 0.20 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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
70019
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

Eight lines of evidence are available in the administrative record to assess this pollutant. LOEs No. 27212 and 7669 are replaced by the LOE No. 46761 and 7649, respectively because they are assessed using the updated objective. None of samples exceed the water quality objectives.

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 dissolved fraction and six total fraction water samples exceeded the CTR criteria for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed.

None of 11 dissolved fraction and non of 2 total fraction water samples exceeded the CTR criteria for the "Municipal & Domestic Supply" beneficial use assessed. Ten total fraction samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

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.
 
 
Line of Evidence (LOE) for Decision ID 70019, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128869
 
Pollutant: 1,2-Dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Dichloroethane, 1,2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-Dichloroethane criteria for the protection of human health from consumption of organisms only is 99 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70019, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127965
 
Pollutant: 1,2-Dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichloroethane, 1,2-. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-Dichloroethane criterion for the protection of human health from the consumption of water and organisms is 0.38 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70019, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34783
 
Pollutant: 1,2-Dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-Dichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-Dichloroethane criterion for the protection of human health from the consumption of water and organisms is 0.38 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70019, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 46761
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | 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: 17
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. 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 only from aquatic systems were used for the following constituents: 71 ug/l Benzene, 360 ug/l Bromoform, 46 ug/l Dichlorobromomethane, 99 ug/l 1,2-Dichloroethane, 39 ug/l 1,2-Dichloropropane, 50 ug/l Hexachlorobutadiene, 8.85 ug/l Tetrachloroehtylene, 42 ug/l 1,1,2-Trichloroethane, and 81 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 70019, 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 70019, 1,2-Dichloroethane
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34767
 
Pollutant: 1,2-Dichloroethane
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-Dichloroethane.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-Dichloroethane criteria for the protection of human health from consumption of organisms only is 99 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70019, 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 70019, 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
79867
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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

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 dissolved fraction and none of six total fraction water samples exceeded the California 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.
 
 
Line of Evidence (LOE) for Decision ID 79867, 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)
 
Line of Evidence (LOE) for Decision ID 79867, 1,2-Dichloroethylene,-trans
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127763
 
Pollutant: 1,2-Dichloroethylene,-trans
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Dichloroethylene, trans 1,2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-trans-dichlorethylene criteria for the protection of human health from consumption of organisms only is 140,000 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79867, 1,2-Dichloroethylene,-trans
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34819
 
Pollutant: 1,2-Dichloroethylene,-trans
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-trans-dichlorethylene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The 1, 2-trans-dichlorethylene criteria for the protection of human health from consumption of organisms only is 140,000 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 79867, 1,2-Dichloroethylene,-trans
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127762
 
Pollutant: 1,2-Dichloroethylene,-trans
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Dichloroethylene, trans 1,2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for trans-1, 2-Dichloroethene is 0.01 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79867, 1,2-Dichloroethylene,-trans
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34735
 
Pollutant: 1,2-Dichloroethylene,-trans
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-trans-dichlorethylene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for trans-1, 2-Dichloroethene is 10 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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
104213
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 1,3,5-Trimethylbenzene
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 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 this pollutant. None of the samples exceed the objective(s).

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. Zero of 15 dissolved fraction samples colleced 2002-2004 exceeded the objective as no evaluation guideline for the dissolved fraction 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.

Zero of four total fraction samples exceeded the Division of Drinking Water Notification Level.

This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104213, 1,3,5-Trimethylbenzene
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 104213, 1,3,5-Trimethylbenzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128490
 
Pollutant: 1,3,5-Trimethylbenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Trimethylbenzene, 1,3,5-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: Drinking water notification levels are published by the Division of Drinking Water and are for chemicals for which there is no drinking water MCL. If a notification level is exceeded, local government notification is required and customer notification is recommended. The criteria for 1,3,5-Trimethylbenzene is 0.33 mg/L.
Guideline Reference: Drinking Water Notification and Response Levels: An Overview
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104215
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 2-Chlorotoluene
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.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the objective(s).

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. Zero of 15 dissolved fraction samples colleced 2002-2004 exceeded the objective as no evaluation guideline for the dissolved fraction 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.

Zero of four total fraction samples exceeded the USEPA's Drinking Water Health advisory.

This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104215, 2-Chlorotoluene
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)
 
Line of Evidence (LOE) for Decision ID 104215, 2-Chlorotoluene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 129003
 
Pollutant: 2-Chlorotoluene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Chlorotoluene, 2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: USEPA's Drinking Water Health advisory for life-time exposure to o-chlorotoluene is a concentration of 100 ug/L
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104219
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 2-Methylnaphthalene
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. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List.

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

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. Zero of 15 sediment samples and dissolved fraction water samples collected 2002-2004 exceeded the objective as no evaluation guideline 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.

Zero of six total fraction water samples exceeded the USEPA expected safe lifetime exposure limit in drinking water.

The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104219, 2-Methylnaphthalene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127810
 
Pollutant: 2-Methylnaphthalene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Methylnaphthalene, 2-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The USEPA expected safe lifetime exposure limit in drinking water for Methylnapthalene, 2-, calculated using the IRIS Reference Dose, is 28 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.004 mg/kg/day as the reference dose.
Guideline Reference: IRIS Reference Summary (Various Pollutants)
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104219, 2-Methylnaphthalene
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)
 
Line of Evidence (LOE) for Decision ID 104219, 2-Methylnaphthalene
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)
 
 
DECISION ID
104220
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 4-Chlorotoluene
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.

Two lines of evidence are available in the administrative record to assess this pollutant.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing this water segment-pollutant combination 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. Zero of 15 dissolved fraction water samples collected 2002-2004 exceeded the objective as no evaluation guideline 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.

Zero of four total fraction water samples exceeded the USEPA expected safe lifetime exposure limit in drinking water.

The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104220, 4-Chlorotoluene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 129004
 
Pollutant: 4-Chlorotoluene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Chlorotoluene, 4-.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: USEPA's Drinking Water Health advisory for life-time exposure to p-chlorotoluene is a concentration of 100 ug/L
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104220, 4-Chlorotoluene
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
70213
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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

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 dissolved fraction and non of 5 total fraction 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.
 
 
Line of Evidence (LOE) for Decision ID 70213, Acenaphthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127707
 
Pollutant: Acenaphthene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Acenaphthene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Acenaphthene criteria for the protection of human health from consumption of organisms only is 2,700 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70213, 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)
 
Line of Evidence (LOE) for Decision ID 70213, 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 70213, Acenaphthene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128823
 
Pollutant: Acenaphthene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Acenaphthene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Acenaphthene criteria for the protection of human health from the consumption of water and organisms is 1,200 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
71594
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: Do Not List on 303(d) list (TMDL required list)(2016)
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 3.5 of the Listing Policy. Under these sections 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 samples exceed the water quality objectives.

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 dissolved fraction and none of ten total fraction water samples exceeded the CTR criteria.
None of seven fish tissue samples exceeded NAS guidelines.
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.
 
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34821
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criteria for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127467
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Aldrin.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128912
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Aldrin. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criteria for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2010-10-05 to 2013-11-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128911
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Aldrin. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criteria for the protection of human health from consumption of organisms only is 0.00014 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2010-10-05 to 2013-11-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34805
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criteria for the protection of human health from consumption of organisms only is 0.00014 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127456
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Aldrin.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126287
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality standard for Aldrin. Data were collected for 1 fish species (1 composite(s) of Common Carp each composed of 5 fish per composite).
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP Sportfish Rivers and Streams.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data was collected from 1 station(s) with the station code(s): 715CRBLYT.
Temporal Representation: Data for this line of evidence were collected between 2011-05-10 and 2011-05-10
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126638
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows 0 of the 5 samples exceeded the water quality standard for Aldrin. Data were collected for 4 fish species (1 composite(s) of Flathead Catfish each composed of 5 fish per composite, 1 composite(s) of Channel Catfish each composed of 2 fish per composite, 1 composite(s) of Common Carp each composed of 5 fish per composite, 1 composite(s) of Striped Bass each composed of 5 fish per composite).
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data was collected from 1 station(s) with the station code(s): 715CRSQLK.
Temporal Representation: Data for this line of evidence were collected between 2014-10-07 and 2014-10-28
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 45993
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: Fish tissue analysis
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Aldrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference: RWB7 Fish Tissue Study 2004
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: 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 (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected on a single day 12/7/2004.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126637
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows 0 of the 5 samples exceeded the water quality standard for Aldrin. Data were collected for 4 fish species (1 composite(s) of Flathead Catfish each composed of 5 fish per composite, 1 composite(s) of Channel Catfish each composed of 2 fish per composite, 1 composite(s) of Common Carp each composed of 5 fish per composite, 1 composite(s) of Striped Bass each composed of 5 fish per composite).
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data was collected from 1 station(s) with the station code(s): 715CRSQLK.
Temporal Representation: Data for this line of evidence were collected between 2014-10-07 and 2014-10-28
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34825
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Aldrin.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 71594, 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)
 
Line of Evidence (LOE) for Decision ID 71594, Aldrin
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126289
 
Pollutant: Aldrin
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality standard for Aldrin. Data were collected for 1 fish species (1 composite(s) of Common Carp each composed of 5 fish per composite).
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP Sportfish Rivers and Streams.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference: National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
 
Spatial Representation: Data was collected from 1 station(s) with the station code(s): 715CRBLYT.
Temporal Representation: Data for this line of evidence were collected between 2011-05-10 and 2011-05-10
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104228
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Alkalinity as CaCO3
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 CWA 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.

Zero of ten sample(s) exceed the criteria for the protection of freshwater aquatic life (National Recommended Water Quality Criteria, 2009) for the "Cold Freshwater Habitat" beneficial use assessed.

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 CWA 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. Zero of ten sample(s) exceed the criteria for the protection of freshwater aquatic life (National Recommended Water Quality Criteria, 2009).

This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2
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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104228, Alkalinity as CaCO3
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128990
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 10
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Alkalinity as CaCO3.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The Alkalinity as CaCO3 criteria for the protection of freshwater aquatic life is 20000 ug/L (National Recommended Water Quality Criteria, 2009). 
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70956
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

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 the California Primary MCL.
None of 33 water samples exceeded the California Secondary 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.
 
 
Line of Evidence (LOE) for Decision ID 70956, Aluminum
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35178
 
Pollutant: Aluminum
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: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Aluminum.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: The California Secondary MCL for aluminum is 0.2 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Secondary Maximum Contaminant Levels and Compliance. CCR title 22 section 64449.
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70956, 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)
 
Line of Evidence (LOE) for Decision ID 70956, 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 70956, Aluminum
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126987
 
Pollutant: Aluminum
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 10
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Aluminum.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for aluminum is 0.2 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104406
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Ametryn
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 pollutants are 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. LOE No. 29501 received a use rating of insufficient in a previous assessment cycle because no evaluation guideline was available for this pollutant. None of the samples exceeded 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 three water samples exceeded the USEPA Health Advisory for lifetime exposure to Ametryn as a drinking water level.

None of 14 dissolved fraction water samples collected years 2002-2004 exceeded the guideline as no evaluation guidelines for the dissolved fractions of Ametryn 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.

The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104406, Ametryn
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128481
 
Pollutant: Ametryn
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Ametryn.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The USEPA Health Advisory for lifetime exposure to Ametryn as a drinking water level is a concentration of 0.06 mg/L
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104406, Ametryn
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
78334
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Ammonia
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
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.

Seven 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.

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. Zero of 13 total fraction and zero of one dissolved fraction water samples exceeded the USEPA Temperature and pH-Dependent values of the CCC.

This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.

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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128528
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference: Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2010-10-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128539
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
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 (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as \the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.\""
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2010-10-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128545
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference: Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2010-10-05
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34571
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: None of the 5 samples exceed the water USEPA Temperature and pH-Dependent values of the CCC (Chronic Criterion) for Fish Early Life Stages Present for ammonia. 3 of the 5 data samples are reported as Non-Detect (ND). These 3 ND values are less than or equal to the water quality standard, the value will be considered as meeting the water quality standard, objective, criterion, or evaluation guideline.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Colorado River Basin Region (RWQCB 2006): All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. There is no water quality objective for ammonia in the Water Quality Control Plan, Colorado River Basin. Instead, the USEPA criteria for ammonia was used as Temperature and pH-Dependent Values of the CCC (Chronic Criterion)for Fish Early Life Stages Present.
Objective/Criterion Reference: 1999 Update of Ambient Water Quality Criteria for Ammonia
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample was collected at 715CRIDG1 (Colorado River at Imperial Dam Grates).
Temporal Representation: Samples collected between 10/25/2005 and 10/29/2008.
Environmental Conditions:
QAPP Information: SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128404
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference: Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2011-10-11 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128403
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
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 (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as \the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.\""
Guideline Reference:
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2011-10-11 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78334, Ammonia
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128546
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference: Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2011-10-11 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70457
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: Do Not List on 303(d) list (TMDL required list)(2016)
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. LOE No. 27211 is replaced by the LOE No. 46763. 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 dissolved fraction and none of six total fraction water samples exceeded the California Toxics Rule criteria protecting human health when consuming water and organisms from these waters.

None of 3 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.
 
 
Line of Evidence (LOE) for Decision ID 70457, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128142
 
Pollutant: Anthracene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Anthracene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Anthracene criteria for the protection of human health from consumption of organisms only is 110,000 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70457, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125880
 
Pollutant: Anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Anthracene .
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Anthrazene from MacDonald et al., 2000a which states that the probable effect concentration for Anthrazene is 845 ug/kg. (dw = Dry Weight)
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected from 1 (Station Codes: 715CRIDG1).
Temporal Representation: Data for this waterbody were collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70457, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 46763
 
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 organisms only from aquatic systems were used for the following constituents: 2700 ug/l Acenaphthene, 0.013 ug/l alpha-BHC, 240 ug/l alpha-Endosulfan, 110000 ug/l Anthracene,0.046 ug/l beta-BHC, 240 ug/l beta-Endosulfan, 21000 ug/l Chlorobenzene, 17000 ug/l o-Dichlorobenzene, 2600 ug/l m-Dichlorobenzene, 2600 ug/l p-Dichlorobenzene, 240 ug/l Endosulfan Sulfate, 0.81 ug/l Endrin, 0.81 ug/l Endrin Aldehyde, 29000 ug/l Ethylbenzene, 370 ug/l Fluoranthene, 14000 ug/l Fluorene, 0.051 ug/l Mercury, 4600 ug/l Nickel, 11000 ug/l Pyrene,and 200000ug/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 70457, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128141
 
Pollutant: Anthracene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Anthracene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Anthracene criteria for the protection of human health from the consumption of water and organisms is 9,600 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70457, 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)
 
Line of Evidence (LOE) for Decision ID 70457, 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 70457, Anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125485
 
Pollutant: Anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Anthracene .
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Anthrazene from MacDonald et al., 2000a which states that the probable effect concentration for Anthrazene is 845 ug/kg. (dw = Dry Weight)
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected from 1 (Station Codes: 715CRIDG1).
Temporal Representation: Data for this waterbody were collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104413
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Antimony
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.

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

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 38 dissolved fraction and none of 38 total fraction water samples exceeded the California Maximum Contaminant Level.

None of 3 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.
 
 
Line of Evidence (LOE) for Decision ID 104413, Antimony
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125919
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Antimony.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for antimony is 0.006 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 104413, Antimony
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126072
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Antimony.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for antimony is 0.006 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 104413, Antimony
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126080
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Antimony.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Antimony criteria for the protection of human health from consumption of organisms only is 4300 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 104413, Antimony
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126099
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Antimony.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Antimony criteria for the protection of human health from consumption of organisms only is 4300 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
 
DECISION ID
70907
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: Do Not List on 303(d) list (TMDL required list)(2016)
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, 3.5 and 3.6 of the Listing Policy. Under sections 3.1 and 3.5 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List.

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

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. One composite fish tissue sample was collected, but not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
None of 25 sediment samples exceeded the sediment quality guideline.
None of 38 total fraction water samples (collected 11/2010-6/2016) exceeded the California MCL of 10 ppb.
None of 17 dissolved fraction water samples (collected 5/2002-5/2005 exceeded the California MCL of 50 ppb.
None of 54 dissolved fraction water samples (collected 10/2005-06/2016) exceeded the California MCL of 10 ppb. (Thirty-eight of the 54 dissolved fraction samples dates and locations overlapped with the total fraction water samples.)
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.
 
 
Line of Evidence (LOE) for Decision ID 70907, 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 70907, 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)
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127070
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 10
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126027
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127071
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 10
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35196
 
Pollutant: Arsenic
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: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Arsenic.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125932
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35223
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Arsenic.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126074
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127073
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 10
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 4 monitoring site(s) (715CRIDG1, 715CRIDU1, 715CRPDDM, 715CRSQLK)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 45994
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Fish fillet
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Fish tissue analysis
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Arsenic. One composite (6 fish per composite) were generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Fish Tissue Study 2004
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: The modified OEHHA Fish Contaminant Goal for arsenic in fish tissue is 0.0034 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. It is assumed that 10% of the total arsenic is present as inorganic arsenic. This constituent is a carcinogen therefore the risk level is set to one in a million.
Guideline Reference: Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
  Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected on a single day 12/7/2004.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125425
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Arsenic .
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Arsenic from MacDonald et al., 2000a which states that the probable effect concentration for Arsenic is 33 mg/kg. (dw = Dry Weight)
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected from 1 (Station Codes: 715CRIDG1).
Temporal Representation: Data for this waterbody were collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125499
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Arsenic .
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Arsenic from MacDonald et al., 2000a which states that the probable effect concentration for Arsenic is 33 mg/kg. (dw = Dry Weight)
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected from 1 (Station Codes: 715CRIDG1).
Temporal Representation: Data for this waterbody were collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35199
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 5 samples exceed the criterion for Arsenic.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for arsenic is 33 mg/Kg dry weight (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: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-4/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125959
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126039
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, Arsenic
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125937
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
Line of Evidence (LOE) for Decision ID 70907, 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 70907, 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)
 
 
DECISION ID
70848
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: Do Not List on 303(d) list (TMDL required list)(2016)
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 16 dissolved fraction and none of 9 total fraction 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.
 
 
Line of Evidence (LOE) for Decision ID 70848, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35245
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Atrazine.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Atrazine is 1 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70848, 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):
 
Line of Evidence (LOE) for Decision ID 70848, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35266
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Atrazine.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental phyusiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Atrazine is 43 ug/L.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70848, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127270
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Atrazine.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a \less-than\" value (for example, <1,500) and may underestimate toxicity."
Guideline Reference: OPP Aquatic Life Benchmarks
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70848, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127269
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Atrazine.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Atrazine is 0.001 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70848, Atrazine
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128624
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Atrazine.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a \less-than\" value (for example, <1,500) and may underestimate toxicity."
Guideline Reference: OPP Aquatic Life Benchmarks
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (715CRIDG1)
Temporal Representation: The samples were collected between the dates of 2010-10-05 and 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
104297
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: 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: 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.

Four lines of evidence are available in the administrative record to assess this pollutant. LOE No. 29495 received a use rating of insufficient in a previous assessment cycle because no evaluation guideline was available for this pollutant. However, an evaluation guideline for Azinphos-methyl (Guthion) is available in later cycles, but results could not be quantified with the level of certainty required by the Listing Policy.

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. LOE No. 29495 - Zero of 15 samples exceeded the guideline as no evaluation guideline was available for this pollutant. However, an evaluation guideline for Azinphos-methyl (Guthion) is available in later cycles, but results could not be quantified with the level of certainty required by the Listing Policy.

Nine water samples were collected for Azinphos Methyl (Guthion), but the results were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy. This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 104297, Azinphos-methyl (Guthion)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128924
 
Pollutant: Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Azinphos Methyl. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) expressed as a 4-day average for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data was collected from 1 station(s) (Station Code(s) 715CRIDG1).
Temporal Representation: Date for this waterbody was collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104297, Azinphos-methyl (Guthion)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35308
 
Pollutant: Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-10/29/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 104297, Azinphos-methyl (Guthion)
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128217
 
Pollutant: Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Azinphos Methyl. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) expressed as a 4-day average for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data was collected from 1 station(s) (Station Code(s) 715CRIDG1).
Temporal Representation: Date for this waterbody was collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 104297, Azinphos-methyl (Guthion)
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
104298
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
Pollutant: Barium
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.

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 38 samples exceeded the California Maximum Contaminant Level.
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.
 
 
Line of Evidence (LOE) for Decision ID 104298, Barium
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 126103
 
Pollutant: Barium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality standard for Barium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for barium is 1 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (USGS-09427520, USGS-09429490)
Temporal Representation: The samples were collected between the dates of 2010-11-23 and 2016-06-22
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data which does not require a QAPP.
 
 
DECISION ID
79507
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: Do Not List on 303(d) list (TMDL required list)(2016)
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.

Seven lines of evidence are available in the administrative record to assess this pollutant. LOE No. 27212 is replaced by the LOE No. 46761 because it was reassessed using the updated 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 dissolved fraction and none of six total fraction water samples exceeded the CTR criteria.
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.
 
 
Line of Evidence (LOE) for Decision ID 79507, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 34995
 
Pollutant: Benzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Benzene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Benzene is 1 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 79507, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128070
 
Pollutant: Benzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality standard for Benzene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Benzene criteria for the protection of human health from consumption of organisms only is 71 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2013-04-15 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79507, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35356
 
Pollutant: Benzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Benzene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Benzene criteria for the protection of human health from consumption of organisms only is 71 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates - 715CRIDG1]
Temporal Representation: Data was collected over the time period 10/25/2005-5/3/2006.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2002) was followed.
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 79507, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 46761
 
Pollutant: 1,1,2-Trichloroethane | 1,2-Dichloroethane | 1,2-Dichloropropane | Benzene | Bromoform | 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: 17
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. 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 only from aquatic systems were used for the following constituents: 71 ug/l Benzene, 360 ug/l Bromoform, 46 ug/l Dichlorobromomethane, 99 ug/l 1,2-Dichloroethane, 39 ug/l 1,2-Dichloropropane, 50 ug/l Hexachlorobutadiene, 8.85 ug/l Tetrachloroehtylene, 42 ug/l 1,1,2-Trichloroethane, and 81 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 79507, 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)
 
Line of Evidence (LOE) for Decision ID 79507, 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 79507, Benzene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 127710
 
Pollutant: Benzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Benzene. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Benzene is 0.001 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2013-04-15 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70458
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: Do Not List on 303(d) list (TMDL required list)(2016)
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. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List.

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

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 24 sediment samples exceeded the sediment quality guideline.
None of six total fraction and none of 11 dissolved fraction water samples exceed CTR criteria.
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.
 
 
Line of Evidence (LOE) for Decision ID 70458, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128495
 
Pollutant: Benzo(a)anthracene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Benz(a)anthracene. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Benzo(a)anthracene criterion for the protection of human health from the consumption of water and organisms is 0.0044 ug/L (California Toxics Rule, 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: Data was collected from 2 station(s) (Station Code(s) 715CRIDG1, 715CRPDDM).
Temporal Representation: Date for this waterbody was collected over the date range 2011-05-10 to 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70458, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 128065
 
Pollutant: Benzo(a)anthracene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Benz(a)anthracene.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Benzo(a)anthracene criteria for the protection of human health from consumption of organisms only is 0.049 ug/L (California Toxics Rule, 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: The samples were collected at 2 monitoring site(s) (715CRIDG1, 715CRPDDM)
Temporal Representation: The samples were collected between the dates of 2011-05-10 and 2013-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70458, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125518
 
Pollutant: Benzo(a)anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Benz(a)anthracene .
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The evaluation guideline for Benz[a]anthrazene from MacDonald et al., 2000a which states that the probable effect concentration for Benz[a]anthrazene is 1050 ug/kg. (dw = Dry Weight)
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected from 1 (Station Codes: 715CRIDG1).
Temporal Representation: Data for this waterbody were collected over the date range 2010-10-05 to 2011-10-11
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 70458, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 35331
 
Pollutant: Benzo(a)anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Benz(a)anthracene.
Data Reference: RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for Benzo(a)anthracene is 1050 ug/Kg dry weight (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: Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam) was collected at 1 monitoring site [ Colorado River at Imperial Dam Grates]
Temporal Representation: Data was collected over the time period 10/25/2005-4/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 70458, Benzo(a)anthracene
Region 7     
Colorado River and Associated Lakes and Reservoirs (Lake Havasu Dam to Imperial Dam)
 
LOE ID: 125836
 
Pollutant: Benzo(a)anthracene
LOE Subgroup: Pollutant-Sediment
Matrix: