Final California 2024 Integrated Report (303(d) List/305(b) Report)

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139965, Alkalinity as CaCO3	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256624

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139965, Alkalinity as CaCO3	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256626

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139965, Alkalinity as CaCO3	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256623

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139938	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Allethrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139938, Allethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256799

Pollutant:

Allethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Allethrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for Allethrin is the USEPA Aquatic Life Benchmark of 1.05 ug/L for an invertebrate (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139938, Allethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256740

Pollutant:

Allethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Allethrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for Allethrin is the USEPA Aquatic Life Benchmark of 1.05 ug/L for an invertebrate (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	153948	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Aluminum
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	During the 2024 cycle, the 1988 National Recommended Water Quality Criteria used to assess aluminum data was replaced with U.S. EPA’s 2018 Final Recommended Aquatic Life Criteria for Aluminum in Freshwater. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 153948, Aluminum	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

314991

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Aluminum.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The aluminum criterion for the protection of aquatic life, is pH, total hardness, and dissolved organic carbon (DOC) dependent. When total hardness or DOC data were not available, default values based on the level III ecoregions developed by U.S EPA were substituted (EPA, 2018). When pH data were not available, the median pH value for the ecoregion, a pH value from a comparable waterbody, or a pH value from a local study in the same waterbody was used as a comparable surrogate.

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 153948, Aluminum	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

315016

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Aluminum.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 153948, Aluminum	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

315022

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Aluminum.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 153948, Aluminum	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

314942

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Aluminum.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	150489	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Ammonia
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 150489, Ammonia	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256922

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listing in the Los Angeles Region Basin Plan for the 30-day Average Objective for Ammonia-N for Freshwaters Applicable to Waters Subject to the “Early Life Present” Condition.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150489, Ammonia	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256902

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150489, Ammonia	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256903

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150489, Ammonia	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

256944

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139941	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139941, Antimony	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257445

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139941, Antimony	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257208

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139941, Antimony	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257226

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139941, Antimony	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257425

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139943	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257382

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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 is 150 ug/L. The conversion factor used to convert the total fraction criterion for arsenic to dissolved fraction criterion is 1. Therefore all data was considered to be representative of the dissolved fraction. (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: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257359

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257328

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257505

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

245541

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Arsenic .

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for arsenic is the probable effect concentration (PEC) of 33 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139943, Arsenic	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

245641

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for arsenic is the probable effect concentration (PEC) of 33 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 4.


DECISION ID	151111	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Benthic Community Effects
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects. Two line(s) of evidence evaluating benthic-macroinvertebrate bioassessment data is/are available in the administrative record to assess this indicator. Zero of three benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. These data indicate that the waterbody is likely unimpaired for Benthic Community Effects and therefore no other pollutant LOEs need be associated with this decision at this time. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this waterbody segment 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 three benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. Therefore, this water body is not exceeding the water quality threshold for the protection of the COLD beneficial use. The available information indicates that the waterbody/pollutant combination should not be placed on the 303(d) List of impaired waters at this time. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 151111, Benthic Community Effects	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

305382

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for 405WE0777 to determine beneficial use support and the results are as follows: 0 of 1 samples exceeded the threshold. CSCI scores were from 1.19983619 to 1.19983619.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

Samples were collected from station 405WE0777.

Temporal Representation:

Samples were collected from 6/20/2001 to 6/20/2001.

Environmental Conditions:

QAPP Information:

Data were collected using EPA Environmental Monitoring & Assessment Program protocols

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 151111, Benthic Community Effects	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

96063

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

The CSCI scores for this water body are 1.182189 and 0.996147. This site is above the 0.79 threshold, and is therefore meeting the water quality objective for the aquatic life beneficial use. This water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI.

Data Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Complete data set for all CSCI reference sites for the entire State.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rhen, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Environmental Management. Volume 35, number 1 (2005): pp. 1-13

Spatial Representation:

Sampling was done at SGUR103 and SGUR00428.

Temporal Representation:

Sampling was done on 8/3/2011.
.

Environmental Conditions:

QAPP Information:

Samples were collected for the SWAMP RWB4 Stormwater Monitoring Council CY 2008 following SWAMP protocols and data were stored in the SWAMP database.

QAPP Information Reference(s):


DECISION ID	139944	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139944, Beryllium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257715

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Beryllium.

Data Reference:

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139944, Beryllium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257734

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Beryllium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139944, Beryllium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257748

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Beryllium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139944, Beryllium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257701

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Beryllium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139963	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Bifenthrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139963, Bifenthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257753

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139963, Bifenthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246121

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for bifenthrin is the median lethal concentration (LC50) of 0.43 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.43 ug/g is the geometric mean of LC50 values for bifenthrin (Amweg et al., 2005 and Amweg and Weston, 2007).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139963, Bifenthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246076

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139963, Bifenthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257865

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139945	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246259

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for cadmium is the probable effect concentration (PEC) of 4.98 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258079

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved cadmium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 2.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258080

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246262

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for cadmium is the probable effect concentration (PEC) of 4.98 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257972

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139945, Cadmium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

257906

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139946	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139946, Chloride	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244068

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data from the San Gabriel River Regional Monitoring Program to determine beneficial use support. The results are as follows: zero out of two samples exceed the criterion for chloride.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Chloride in West Fork San Gabriel River and its Tributaries of 10 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC04524 (34.247611, -118.033674), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/15/2017 and 7/19/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139946, Chloride	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244054

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Chloride in West Fork San Gabriel River and its Tributaries of 10 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC00428 (34.248109, -118.049761), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/1/2016 and 6/15/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139969	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Chromium
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246660

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for chromium is the probable effect concentration (PEC) of 111 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258760

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved chromium (III) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is is hardness dependent as described in Table 1 of paragraph (b)(1). The value calculated when using a default hardness of 100 mg/L is 180 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

246934

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for chromium is the probable effect concentration (PEC) of 111 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258656

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258528

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139969, Chromium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258693

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139947	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259161

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved copper criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 9 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258910

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259120

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

258859

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247724

Pollutant:

Copper

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for copper is the probable effect concentration (PEC) of 149 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139947, Copper	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247440

Pollutant:

Copper

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for copper is the probable effect concentration (PEC) of 149 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139966	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Cyfluthrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139966, Cyfluthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259306

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139966, Cyfluthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247489

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for cyfluthrin is the median lethal concentration (LC50) of 1.1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.1 ug/g is the geometric mean of LC50 values for cyfluthrin (Amweg et al., 2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139966, Cyfluthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259241

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139966, Cyfluthrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247556

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139968	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Cyhalothrin, Lambda
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139968, Cyhalothrin, Lambda	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247715

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for lambda-cyhalothrin is the median lethal concentration (LC50) of 0.44 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.44 ug/g is the geometric mean of LC50 values for lambda-cyhalothrin (Amweg et al., 2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139968, Cyhalothrin, Lambda	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262610

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of lambda-cyhalothrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139968, Cyhalothrin, Lambda	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262790

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139968, Cyhalothrin, Lambda	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247649

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139964	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Cypermethrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139964, Cypermethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259615

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139964, Cypermethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

259495

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139964, Cypermethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247863

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for cypermethrin is the median lethal concentration (LC50) of 0.3 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.3 ug/g is the geometric mean of LC50 values for cypermethrin from Maund et al., (2002).

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139964, Cypermethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247964

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139967	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Deltamethrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139967, Deltamethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

260042

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139967, Deltamethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247778

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for deltamethrin is the median lethal concentration (LC50) of 0.79 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.79 ug/g is the geometric mean of LC50 values for deltamethrin (Amweg et al., 2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139967, Deltamethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

247857

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139967, Deltamethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

260058

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139971	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Esfenvalerate/Fenvalerate
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139971, Esfenvalerate/Fenvalerate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261549

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Esfenvalerate

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139971, Esfenvalerate/Fenvalerate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261516

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Esfenvalerate

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139970	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Fenpropathrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139970, Fenpropathrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261338

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139970, Fenpropathrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248568

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fenpropathrin is the median lethal concentration (LC50) of 1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1 ug/g is the geometric mean of LC50 values for fenpropathrin from Ding et al., ( 2011).

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139970, Fenpropathrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261459

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139970, Fenpropathrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248628

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139939	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Fenvalerate
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139939, Fenvalerate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261729

Pollutant:

Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Fenvalerate.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fenvalerate is the LC50 of 1.13 ug/L for fathead minnow, Pimephales promelas. (USEPA Office of Pesticide Programs Ecotoxicity database)

Guideline Reference:

OPP Pesticide Ecotoxicity Database.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139939, Fenvalerate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

261748

Pollutant:

Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Fenvalerate.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fenvalerate is the LC50 of 1.13 ug/L for fathead minnow, Pimephales promelas. (USEPA Office of Pesticide Programs Ecotoxicity database)

Guideline Reference:

OPP Pesticide Ecotoxicity Database.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139962	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Fipronil
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139962, Fipronil	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248710

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fipronil. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil is the median lethal concentration (LC50) of 0.13 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Effect of sediment-associated pyrethroids, fipronil, and metabolites on Chironomus tentans growth rate, body mass, condition index, immobilization, and survival. Environ. Toxicol. Chem. 27(12):2582-2590.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Date for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139962, Fipronil	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248693

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fipronil. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil is the median lethal concentration (LC50) of 0.13 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Date for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139972	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Fipronil Sulfide
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139972, Fipronil Sulfide	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248487

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil sulfide is the median lethal concentration (LC50) of 0.16 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139972, Fipronil Sulfide	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248468

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil sulfide is the median lethal concentration (LC50) of 0.16 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139973	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Fipronil Sulfone
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139973, Fipronil Sulfone	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248529

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil sulfone is the median lethal concentration (LC50) of 0.12 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139973, Fipronil Sulfone	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248511

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for fipronil sulfone is the median lethal concentration (LC50) of 0.12 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al., 2008).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139948	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Iron
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262520

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentrations are intended protect freshwater aquatic organisms from chronic exposures and are expressed as 4-day average concentrations. The evaluation guideline for Iron is 1,000 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262376

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262464

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262446

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262466

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262518

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262377

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139948, Iron	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262318

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139949	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

248820

Pollutant:

Lead

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for lead is the probable effect concentration (PEC) of 128 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

249283

Pollutant:

Lead

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for lead is the probable effect concentration (PEC) of 128 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263029

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved lead criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 2.5 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262885

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262992

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139949, Lead	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

262982

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	150029	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Mercury
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263359

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263453

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263663

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

249720

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for mercury is the probable effect concentration (PEC) of 1.06 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263333

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263321

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263200

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263375

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263395

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150029, Mercury	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

249550

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for mercury is the probable effect concentration (PEC) of 1.06 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139950	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Nickel
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263823

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved nickel criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 52 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263940

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

250097

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for nickel is the probable effect concentration (PEC) of 48.6 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

264106

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

263923

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139950, Nickel	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

249872

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for nickel is the probable effect concentration (PEC) of 48.6 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139951	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139951, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244069

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data from the San Gabriel River Regional Monitoring Program to determine beneficial use support. The results are as follows: zero out of one samples exceed the criterion for Nitrate/Nitrite (Nitrite + Nitrate as N).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Nitrate/Nitrite (Nitrite + Nitrate as N) in West Fork San Gabriel River and its Tributaries of 2 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC04524 (34.247611, -118.033674), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 7/19/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139951, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244055

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Nitrate/Nitrite (Nitrite + Nitrate as N) in West Fork San Gabriel River and its Tributaries of 2 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC00428 (34.248109, -118.049761), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/15/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	150030	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 150030, Nitrogen, Nitrate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

302290

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-34) states that: Waters shall not exceed 10 mg/L as nitrate-nitrogen (NO3-N).

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150030, Nitrogen, Nitrate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

302398

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-34) states that: Waters shall not exceed 10 mg/L as nitrate-nitrogen (NO3-N).

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150030, Nitrogen, Nitrate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

302432

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-34) states that: Waters shall not exceed 10 mg/L as nitrate-nitrogen (NO3-N).

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 150030, Nitrogen, Nitrate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

302404

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-34) states that: Waters shall not exceed 10 mg/L as nitrate-nitrogen (NO3-N).

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	151941	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

307807

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-39) states that: The dissolved oxygen content of all surface waters designated as COLD shall not be depressed below 6 mg/L as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

308307

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-39) states that: The dissolved oxygen content of all surface waters designated as both COLD and SPWN shall not be depressed below 7 mg/L as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

308258

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

307967

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

307889

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-39) states that: The dissolved oxygen content of all surface waters designated as WARM shall not be depressed below 5 mg/L as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151941, Oxygen, Dissolved	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

307919

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139974	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Permethrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139974, Permethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

264759

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Permethrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139974, Permethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

250853

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for permethrin is the median lethal concentration (LC50) of 8.9 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 8.9 ug/g is the geometric mean of LC50 values for permethrin (Amweg et al., 2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139974, Permethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

250828

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139974, Permethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

264878

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Permethrin

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139942	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Prallethrin
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139942, Prallethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265079

Pollutant:

Prallethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prallethrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for prallethrin is the USEPA Aquatic Life Benchmark of 0.65 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139942, Prallethrin	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265568

Pollutant:

Prallethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prallethrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for prallethrin is the USEPA Aquatic Life Benchmark of 0.65 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139961	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Pyrethroids
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139961, Pyrethroids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265424

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139961, Pyrethroids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

250895

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for the protection of aquatic life from pyrethroids is one toxic unit. Individual pyrethroid concentrations in sediment were normalized to organic carbon content, divided by the respective LC50 and then summed. A sum over over one toxic unit is an exceedance of the evaluation guideline (Amweg et al. 2006).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Guideline Reference:

Compilation of freshwater OC-normalized sediment toxicity data for pyrethroids

Guideline Reference:

Pyrethroid insecticides and sediment toxicity in urban creeks from California and Tennessee. Environmental Science and Technology, 40(5): 1700-1706

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139961, Pyrethroids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265454

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-01 to 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139961, Pyrethroids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

251025

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Guideline Reference:

Compilation of freshwater OC-normalized sediment toxicity data for pyrethroids

Guideline Reference:

Pyrethroid insecticides and sediment toxicity in urban creeks from California and Tennessee. Environmental Science and Technology, 40(5): 1700-1706

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139953	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Selenium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265734

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266232

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266230

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Selenium.

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2018-07-19 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265908

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265866

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Selenium.

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2018-07-19 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266233

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265982

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139953, Selenium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265909

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139954	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Silver
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139954, Silver	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266249

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Silver.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved silver criterion maximum concentration (CMC) to protect aquatic life in freshwater is hardnesss dependent. The criterion when calculated using a default hardness of 100 mg/L is 3.4 ug/L. This criterion was divided by 2 in order to better represent a CMC value as specified in footnote (g) of Table (b)(1) of the California Toxics Rule, 2000.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139954, Silver	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266295

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Silver.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139955	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139955, Sulfates	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244070

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Sulfates in West Fork San Gabriel River and its Tributaries of 30 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC04524 (34.247611, -118.033674), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/15/2017 and 7/19/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139955, Sulfates	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244056

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data from the San Gabriel River Regional Monitoring Program to determine beneficial use support. The results are as follows: two out of two samples exceed the criterion for Sulfates.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Sulfates in West Fork San Gabriel River and its Tributaries of 30 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC00428 (34.248109, -118.049761), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/1/2016 and 6/15/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139940	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	T-Fluvalinate
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139940, T-Fluvalinate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266927

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for T-Fluvalinate.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for tau-fluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139940, T-Fluvalinate	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

266988

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for T-Fluvalinate.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for tau-tluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139956	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Temperature, water
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267311

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: The natural receiving water temperature of all regional waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267072

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267286

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Inland Fishes of California (Moyle 2002) identifies a temperature range below 21 degrees C as suitable for survival with minimum mortality (page 276).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267051

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region (page 3-45) states that: For waters designated WARM, water temperature shall not be altered by more than 5 °F above the natural temperature. At no time shall these WARM-designated waters be raised above 80 °F as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267282

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139956, Temperature, water	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267128

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Inland Fishes of California (Moyle 2002) identifies a temperature range below 21 degrees C as suitable for survival with minimum mortality (page 276).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139957	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Thallium
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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 139957, Thallium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267441

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139957, Thallium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267351

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139957, Thallium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267660

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139957, Thallium	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267396

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)

Guideline Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2016-06-01

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139958	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Total Dissolved Solids
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, and five exceedances are necessary to list. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139958, Total Dissolved Solids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244064

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data from the San Gabriel River Regional Monitoring Program to determine beneficial use support. The results are as follows: one out of one samples exceed the criterion for Total Dissolved Solids.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Total Dissolved Solids in West Fork San Gabriel River and its Tributaries of 250 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC00428 (34.248109, -118.049761), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/15/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139958, Total Dissolved Solids	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

244078

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data from the San Gabriel River Regional Monitoring Program to determine beneficial use support. The results are as follows: one out of two samples exceed the criterion for Total Dissolved Solids.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region lists a site specific objective for Total Dissolved Solids in West Fork San Gabriel River and its Tributaries of 250 mg/L

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Station SMC04524 (34.247611, -118.033674), located in West Fork San Gabriel River and its Tributaries.

Temporal Representation:

Water samples were taken on 6/15/2017 and 7/19/2018 for the San Gabriel River Regional Monitoring Program.

Environmental Conditions:

QAPP Information:

The work was performed in accordance with the quality control and quality assurance provisions of the San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139959	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Turbidity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139959, Turbidity	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268042

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Turbidities of 25 NTU or greater can cause a reduction in juvenile salmonid growth due to interference with their ability to find food (Sigler et al. 1984).

Guideline Reference:

Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139959, Turbidity	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268054

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009).

Guideline Reference:

The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139959, Turbidity	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

267992

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139959, Turbidity	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268185

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Turbidities of 25 NTU or greater can cause a reduction in juvenile salmonid growth due to interference with their ability to find food (Sigler et al. 1984).

Guideline Reference:

Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139960	Region 4
West Fork San Gabriel River and its Tributaries

Pollutant:	Zinc
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268525

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved zinc criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 120 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268530

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268339

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2018-07-19

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

251616

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for zinc is the probable effect concentration (PEC) of 459 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

251626

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for zinc is the probable effect concentration (PEC) of 459 mg/kg dry weight (MacDonald et al., 2000a).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): SMC00428 (SGUR00428).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-06-15 to 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139960, Zinc	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

268529

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.


DECISION ID	139952	Region 4
West Fork San Gabriel River and its Tributaries

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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 139952, pH	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265014

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Los Angeles Basin: the pH for inland surface waters, bays, or estuaries shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139952, pH	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265291

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Los Angeles Basin: the pH for inland surface waters, bays, or estuaries shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC00428 (SGUR00428).

Temporal Representation:

The samples were collected between the dates of 2016-06-01 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139952, pH	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265016

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Los Angeles Basin: the pH for inland surface waters, bays, or estuaries shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):

Field, Habitat, Tissue, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 139952, pH	Region 4
West Fork San Gabriel River and its Tributaries

LOE ID:

265268

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for West Fork San Gabriel River and its Tributaries to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Los Angeles Basin: the pH for inland surface waters, bays, or estuaries shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04524 (SGUR04524).

Temporal Representation:

The samples were collected between the dates of 2017-06-15 and 2017-06-15

Environmental Conditions:

QAPP Information:

Aquatic Bioassay & Consulting Laboratories. 2019. San Gabriel River Regional Monitoring Program.

QAPP Information Reference(s):