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 (Imperial Reservoir to California-Mexico Border)
Water Body ID: CAR7270000020050815175128
Water Body Type: River & Stream
 
DECISION ID
69080
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Selenium
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Delist from 303(d) list (TMDL required list)(2016)
Revision Status Revised
Reason for Delisting: Applicable WQS attained; due to change in WQS
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 3.1 and 3.5 of the Listing Policy. Under section 3.1 and 3.5, a single line(s) of evidence is necessary to assess listing status.

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

(LOE 2968) Three of the five samples exceed the OEHHA Screening Value for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528)

(LOE 46528) Zero of the five samples exceed the OEHHA Fish Contaminant Goal for the "Commercial or Recreational Collection of Fish, Shellfish, or Organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528)

(LOE 126028) Zero of the six samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed, in water, under section 3.1.

(LOE 126092) Zero of the six samples exceed the California Toxics Rule Criterion Continuous Concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed, in water, under section 3.1.

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

(LOE 2968) Three of the five samples exceed the OEHHA Screening Value for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528)

(LOE 46528) Zero of the five samples exceed the OEHHA Fish Contaminant Goal for the "Commercial or Recreational Collection of Fish, Shellfish, or Organisms" beneficial use assessed, in tissue, under section 3.5. (LOE 2968 was replaced by LOE 46528, which was assessed based on the new guideline.)

(LOE 126028) Zero of the six samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed, in water, under section 3.1.

(LOE 126092) Zero of the six samples exceed the California Toxics Rule Criterion Continuous Concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed, in water, under section 3.1.

The sample sizes (with the replacement of LOE 2968 by LOE 46528) are 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 69080, Selenium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126028
 
Pollutant: Selenium
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Selenium.
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 Maximum Contaminant Level for selenium in the Basin Plan is 0.05 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 69080, Selenium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126092
 
Pollutant: Selenium
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Selenium.
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 selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 69080, Selenium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 2968
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 5
Number of Exceedances: 3
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Three out of 5 samples exceeded (TSMP, 2002). A total of 5 filet samples of largemouth bass were collected. Bass were collected in 1992, 1999, and 2001-02. Bass exceeded the guideline in 1999 and 2001-02.
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Colorado River Basin RWQCB Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline: OEHHA Screening Value 2 ug/g.
Guideline Reference: Placeholder reference 2006 303(d)
 
Spatial Representation: Two stations were sampled: about 2 miles downstream of the Needles Marina Resort and from Squaw Lake boat launch ramp to 1/4 mile north of Senator Lake.
Temporal Representation: Samples were collected annually in 1992, 1999 and 2001-02.
Environmental Conditions:
QAPP Information: Toxic Substances Monitoring Program 1992-93 Data Report.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 1996-2000. Department of Fish and Game.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002. Department of Fish and Game.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 69080, Selenium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 46528
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: None of 5 samples exceeded (TSMP, 2002). A total of five filet samples of largemouth bass were collected. Bass were collected in 1992, 1999, and 2001-02. Bass exceeded the guidelines in 1999 and 2001-02.
Data Reference: Toxic Substances Monitoring Program data for years 1992-2002 and Coastal Fish Contamination Program for years 1 and 2. State Water Resources Control Board
  Toxic Substances Monitoring Program 1991 Data Report. 93-1WQ. State Water Resources Control Board (SWRCB), Division of Water Quality. Sacramento, CA.
 
SWAMP Data:
 
Water Quality Objective/Criterion: Colorado River Basin RWQCB Basin Plan: No individual chemical or combinationof chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
 
Evaluation Guideline: OEHHA Fish Contaminant Goals(FCGs) 7.4 mg/kg
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
 
Spatial Representation: Two stations were sampled: about 2 miles downstream of the Needles Marina Resort and from Squaw Lake boat launch ramp to 1/4 mile notrh of Senator Lake.
Temporal Representation: Samples were collected annuallly in 1992, 1999 and 2001-02.
Environmental Conditions:
QAPP Information: Toxic Sustances Monitoring Program 1992-1993 Data Report.

Environmental Chemistry Qaulity Assurance and Data Report for the Toxic Substances Monitoring Program, 1996=2000. Department of Fish and Game.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002. Department of Fish and Game.
QAPP Information Reference(s):
 
 
DECISION ID
101815
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
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 CWA 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.

Zero of five samples exceed the California Maximum Contaminant Level
for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Maximum Contaminant Level
for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of five samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "total" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "dissolved" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" 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 five samples exceed the California Maximum Contaminant Level
for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Maximum Contaminant Level
for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of five samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "total" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "dissolved" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed.

These sample sizes are 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 3.11of 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 101815, Antimony
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126084
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101815, Antimony
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125945
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 5 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101815, Antimony
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126116
 
Pollutant: Antimony
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 5 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101815, Antimony
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126050
 
Pollutant: Antimony
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101816
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Arsenic
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Zero of six samples exceed the California Maximum Contaminant Level
for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Maximum Contaminant Level
for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "total" fraction, for the " Warm Freshwater Habitat " beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "dissolved" fraction, for the " Warm 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 six samples exceed the California Maximum Contaminant Level
for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Maximum Contaminant Level
for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "total" fraction, for the " Warm Freshwater Habitat " beneficial use assessed.

Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "dissolved" fraction, for the " Warm Freshwater Habitat " beneficial use assessed..

These sample sizes are 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 3.11of 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 101816, Arsenic
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126070
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101816, Arsenic
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126088
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101816, Arsenic
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126110
 
Pollutant: Arsenic
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101816, Arsenic
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125978
 
Pollutant: Arsenic
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101817
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
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 CWA 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.

Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" 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 the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed

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 ____samples is needed to determine if a beneficial use is fully supported using table _____.
4. Pursuant to [SECTION 3.11/4.11] 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 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 101817, Barium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126005
 
Pollutant: Barium
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101818
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Beryllium
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 3.1 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.

Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" 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 the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

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 101818, Beryllium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126046
 
Pollutant: Beryllium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Beryllium.
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 beryllium is 0.004 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) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2014-08-27
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
101819
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Boron
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 3.1 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.

Zero of six samples exceed the Division of Drinking Water Notification Level
for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985) protective of various agricultural uses of water (including irrigation of various types of crops and stock watering), for the "Agricultural Supply" 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 six samples exceed the Division of Drinking Water Notification Level
for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985) protective of various agricultural uses of water (including irrigation of various types of crops and stock watering), for the "Agricultural Supply" beneficial use assessed.


The sample sizes are 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 101819, Boron
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126097
 
Pollutant: Boron
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Boron.
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: 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. Notification levels 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 notification level for Boron is 1 mg/L.
Guideline Reference: Drinking Water Notification and Response Levels: An Overview
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101819, Boron
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125966
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Agricultural 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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Boron.
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: 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: Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. The guideline for boron is 700 ug/L (0.7 mg/L).
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101820
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Cadmium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Zero of the Two samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the Two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm 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 the Two samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the Two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed.

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 101820, Cadmium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126131
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.
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: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2015-02-12 and 2015-05-21
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 101820, Cadmium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125942
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.
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 Maximum Contaminant Level for cadmium in the Basin Plan is 0.005 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2015-02-12 and 2015-05-21
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
101821
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the 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.

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

Zero of the six samples exceed the Drinking Water Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six samples exceed the USEPA National Recommended Water Quality Criteria, criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm 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 the six samples exceed the Drinking Water Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six samples exceed the USEPA National Recommended Water Quality Criteria, criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed.

The sample sizes are 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 101821, Chloride
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126002
 
Pollutant: Chloride
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Chloride.
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 Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101821, Chloride
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126003
 
Pollutant: Chloride
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Chloride.
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: 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 Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used: 500 mg/l Chloride (CCR, title 22).
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101823
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Fluoride
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 3.1 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.

Zero of the six samples exceed the California Primary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985, which contains criteria protective of various agricultural uses of water) for the "Agricultural Supply" 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 the six samples exceed the California Primary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985, which contains criteria protective of various agricultural uses of water) for the "Agricultural Supply" beneficial use assessed.

The sample sizes are 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 101823, Fluoride
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125968
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural 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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Fluoride.
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: 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: Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. A 1 mg/L criteria is the recommended maximum concentration of Fluoride in irrigation water.
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101823, Fluoride
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126136
 
Pollutant: Fluoride
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Fluoride.
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: 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 California Primary Maximum Contaminant Level (MCL) for Fluoride, is 2 mg/l.
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101810
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Indicator Bacteria
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 3.3 of the Listing Policy. Under section 3.3, 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 the six sample(s) exceed the Statistical Threshold Value for the " Water Contact Recreation" 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 the six sample(s) exceed the Statistical Threshold Value for the " Water Contact Recreation" beneficial use assessed.

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 101810, Indicator Bacteria
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126138
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and the results are as follows: 0 of the 6 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
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 bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): USGS-09521100
Temporal Representation: The samples were collected between the days of 2014-08-27 and 2016-12-20 .
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
101824
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Lead
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

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

Zero of the six sample(s) exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the one sample(s) exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six sample(s) exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm 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 the six sample(s) exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the one sample(s) exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the six sample(s) exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed.

The sample sizes are 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 101824, Lead
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126094
 
Pollutant: Lead
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Lead.
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 Maximum Contaminant Level for lead in the Basin Plan is 0.015 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2015-05-21 and 2015-05-21
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 101824, Lead
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126076
 
Pollutant: Lead
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Lead.
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 Maximum Contaminant Level for lead in the Basin Plan is 0.015 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101824, Lead
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125970
 
Pollutant: Lead
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Lead.
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: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101827
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
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 3.1 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.

Zero of the 16 samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" 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 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 the 16 samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" 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 101827, Nitrate/Nitrite (Nitrite + Nitrate as N)
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126784
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 16 samples exceeded the water quality standard for Nitrate + Nitrite as N.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate + nitrite (as N) is 10.0 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 3 monitoring site(s) (QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-12-02 and 2012-06-14
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
101828
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Nitrogen, Nitrate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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. Zero of the nine sample(s) exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" 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. One line of evidence is available in the administrative record to assess this pollutant. Zero of the nine sample(s) exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.. 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 101828, Nitrogen, Nitrate
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126700
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 9
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality standard for Nitrate as N.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Nitrate as N is 10000 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: The samples were collected at 4 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35)
Temporal Representation: The samples were collected between the dates of 2010-12-17 and 2011-09-21
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
101782
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Oxygen, Dissolved
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 are available in the administrative record to assess this pollutant.

Four of the 186 samples exceed the Water Quality Control Plan, Colorado River Basin, Warm Water Habitat Objective for the "Warm 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. [Four of the 186 samples exceed the Water Quality Control Plan, Colorado River Basin, Warm Water Habitat Objective for the "Warm Freshwater Habitat" beneficial use assessed.

This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 101782, Oxygen, Dissolved
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126762
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 186
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 4 of 186 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Colorado River Basin, WARM Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 5.0 mg/l at any time.
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 7 monitoring site(s) (COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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
101825
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Sulfates
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 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant.

Zero of six sample(s) exceed the Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" 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 six sample(s) exceed the Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

The 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 101825, Sulfates
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126133
 
Pollutant: Sulfates
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Sulfate.
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: Basin Plan: 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 Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance of 500 mg/l.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101783
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the 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.

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

Zero of 162 samples exceed the Colorado River Basin Region Water Quality Control Plan water quality objective for each of the seven beneficial uses 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 162 samples exceed the Colorado River Basin Region Water Quality Control Plan water quality objective for each of the seven beneficial uses assessed.

This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126705
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Aquaculture
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126710
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126799
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126763
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126811
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126748
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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 101783, pH
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126789
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 162
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water 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:
Guideline Reference:
 
Spatial Representation: The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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
101826
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Manganese
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2031
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 3.1 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.

Six of six samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Six of six samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed.

This exceeds 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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 101826, Manganese
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126102
 
Pollutant: Manganese
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 6
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality standard for Manganese.
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: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin). Aesthetic Qualities. All waters shall be free from substances attributable to wastewater of domestic or industrial origin or other discharges which adversely affect beneficial uses not limited to Producing objectionable color, odor, taste, or turbidity. (Water Quality Control Plan, 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 California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's narrative objective for Aesthetic Qualities and Chemical Constituents. The Secondary MCL for manganese is 0.5 mg/L. (Cal. Code Regs., tit. 22, ยง 64449.)
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101784
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Sodium
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2031
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.

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

Six of the six samples exceed the Drinking Water Standards and Health Advisories (USEPA 2012) health advisory for sodium for individuals on a sodium-restricted diet for the "Municipal & Domestic Supply" beneficial use assessed.

Six of the six samples exceed the Water Quality for Agriculture (published by the Food and Agriculture Organization of the United Nations in 1985) for agricultural uses ( including irrigation of various types of crops and stock watering) criteria for the "Agricultural Supply " beneficial use assessed.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Six of the six samples exceed the Drinking Water Standards and Health Advisories (USEPA 2012) health advisory for sodium for individuals on a sodium-restricted diet for the "Municipal & Domestic Supply" beneficial use assessed.

Six of the six samples exceed the Water Quality for Agriculture (published by the Food and Agriculture Organization of the United Nations in 1985) for agricultural uses ( including irrigation of various types of crops and stock watering) criteria for the "Agricultural Supply " beneficial use assessed.

This exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 101784, Sodium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125984
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 6
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality standard for Sodium.
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: 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: Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 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) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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 101784, Sodium
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126075
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 6
Number of Exceedances: 6
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality standard for Sodium.
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: 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: Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the sodium threshold of 69 mg/L, agricultural uses of water should not be limited.
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101797
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Specific Conductivity
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2031
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.

161 of the 161 samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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.
3.161 of the 161 samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed.
This exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 101797, Specific Conductivity
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126840
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 161
Number of Exceedances: 161
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 161 of 161 samples exceeded the water quality standard for SpecificConductivity.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-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 specific conductance is 900 uS/cm (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 7 monitoring site(s) (COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2012-06-19
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
101798
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Total Dissolved Solids
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2031
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 are available in the administrative record to assess this pollutant.

Six of the six samples exceed the California Secondary Maximum Contaminant Level for the " Municipal & Domestic Supply" beneficial use assessed.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Six of the six samples exceed the California Secondary Maximum Contaminant Level for the " Municipal & Domestic Supply" beneficial use assessed.
This exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 101798, Total Dissolved Solids
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125954
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 6
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality standard for Total Dissolved Solids.
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: 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 Secondary Maximum Contaminant Levels (MCLs) for consumer acceptance objective for total dissolved solids is 500 mg/L.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2016-12-20
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
101799
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Turbidity
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2031
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.

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

52 of the 102 samples exceed the California Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. 52 of the 102 samples exceed the California Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.
This exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
 
Line of Evidence (LOE) for Decision ID 101799, Turbidity
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126033
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 7
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 4 of 7 samples exceeded the water quality standard for Turbidity.
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: 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 surface waters under the Basin Plan's \Chemical Constituents\" objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment. "
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2014-08-27 and 2017-03-14
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 101799, Turbidity
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126726
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 95
Number of Exceedances: 47
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 47 of 95 samples exceeded the water quality standard for Turbidity.
Data Reference: Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.
 
SWAMP Data: Non-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 surface waters under the Basin Plan's \Chemical Constituents\" objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment. "
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 7 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)
Temporal Representation: The samples were collected between the dates of 2010-12-02 and 2012-06-19
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
101822
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
Pollutant: Copper
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Original
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 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence are necessary to assess listing status.

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

Zero of the two samples exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the two samples exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm 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 the two samples exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the two samples exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed.

Zero of the two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed.

The sample sizes are 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 101822, Copper
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125991
 
Pollutant: Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
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: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2016-08-22 and 2016-12-20
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 101822, Copper
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 125992
 
Pollutant: Copper
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
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: 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 copper is 1.0 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2016-08-22 and 2016-12-20
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 101822, Copper
Region 7     
Colorado River (Imperial Reservoir to California-Mexico Border)
 
LOE ID: 126024
 
Pollutant: Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
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 NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
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: 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 copper is 1.0 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 1 monitoring site(s) (USGS-09521100)
Temporal Representation: The samples were collected between the dates of 2016-08-22 and 2016-12-20
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.