Draft 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 138240, Temperature, water	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266790

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138240, Temperature, water	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266870

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138240, Temperature, water	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266852

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138240, Temperature, water	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266890

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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	138236	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	pH
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2009
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. 2 lines of evidence are available in the administrative record to assess this pollutant. 178 of the 681 samples exceed the objective. 120 of the 391 samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. 178 and 681 and 120 of 391 samples exceeded the OBJECTIVE and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265368

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265274

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265183

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265115

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255406

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 11 of 32 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255405

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

126

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 126 samples exceeded the water quality threshold for pH.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-10-12

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265055

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87888

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

234

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Eighty of 234 samples exceeded the objective.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH of all inland surface waters 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:

Samples were collected from the SG-RA2, SG-R4, and SG-R9W stations

Temporal Representation:

Samples were collected approximately once a month from July 2005 to November 2009.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2454

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

284

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Eighty-five samples of 284 total samples exceed the pH objective (LACSD, 2004b).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: The pH of inland surface waters shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges. Ambient pH levels shall not be changed more than 0.5 units from natural conditions as a result of waste discharge.

Objective/Criterion Reference:

NPDES receiving water monitoring reports for Long Beach Water Reclamation Plant (NPDES No. CA0054119), Los Coyotes Water Reclamation Plant (NPDES No. CA0053716), Pomona Water Reclamation Plant (NPDES No. CA0053911), San Jose Creek Water Reclamation Plant (NPDES No. CA0053619), and Whittier Narrows Creek Water Reclamation Plant (NPDES No. CA0054011).

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Six stations.

Temporal Representation:

Measurements were taken weekly between June 2003 and November 2004.

Environmental Conditions:

QAPP Information:

NPDES quality assurance.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138236, pH	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

25299

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

391

Number of Exceedances:

120

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

120 of 391 samples exceeded the Basin Plan water quality objectives for pH in inland surface water bodies. Water quality samples were taken and analyzed for pH in accordance with the Sanitation Districts of Los Angeles County permit monitoring and testing parameters.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan states, "pH of inland surface waters shall not be depressed below 6.5 or raised above 8.5 as a result of wastes discharges."

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The Sanitation Districts of Los Angeles County conducted sampling in San Gabriel River Reach 1 in the following receiving water monitoring stations: station R2 located near Firestone Boulevard; station R31 located 100 feet upstream of the Los Coyotes discharge point; station R4 located at Artesia Boulevard, downstream of the Los Coyotes discharge point; and station R9W located at at the downstream end of the pavement lining (near Atherton Street) in the western low flow channel.

Temporal Representation:

Grab samples were taken and analyzed on a daily and weekly basis from December 2004 to February 2007

Environmental Conditions:

QAPP Information:

Data was collected in compliance with the sampling and monitoring procedures detailed in Sanitation Districts of Los Angeles County (NPDES No. CA0054119) Monitoring and Reporting Program.

QAPP Information Reference(s):

Long Beach Water Reclamation Plant Monitoring and Reporting Program for NPDES No. CA0054119 (County Sanitation Districts of Los Angeles County)


DECISION ID	138251	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	1,1,2-Trichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138251, 1,1,2-Trichloroethane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256091

Pollutant:

1,1,2-Trichloroethane

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 19 samples exceeded the water quality threshold for Trichloroethane, 1,1,2-.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA National Recommended Water Quality Criteria (Gold Book) for freshwater aquatic life protection, chronic Lowest Observed Effect Level is 9,400 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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138251, 1,1,2-Trichloroethane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256080

Pollutant:

1,1,2-Trichloroethane

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Trichloroethane, 1,1,2-.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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 USEPA National Recommended Water Quality Criteria (Gold Book) for freshwater aquatic life protection, chronic Lowest Observed Effect Level is 9,400 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138225	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	2,4,5-TP (Silvex)
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 138225, 2,4,5-TP (Silvex)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252788

Pollutant:

2,4,5-TP (Silvex)

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Trichlorophenoxy)propionic Acid, 2-(2,4,5-.

Data Reference:

WQ data from the MS4 database 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 evaluation guideline for 2,4,5,-TP is 29,000 ug/L, which is the LC50 for Lepomis macrochirus (bluegill) (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

OPP Pesticide Ecotoxicity Database.

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138231	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	2,4-D (2,4-Dichlorophenoxy acetic acid)
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 138231, 2,4-D (2,4-Dichlorophenoxy acetic acid)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252108

Pollutant:

2,4-D (2,4-Dichlorophenoxy acetic acid)

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 evaluation guideline for dichlorophenoxyacetic acid, 2,4- (2,4-D) is the USEPA Aquatic Life Benchmark of 299.2 ug/L for a vascular plant (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138248	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138248, Acrolein	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253354

Pollutant:

Acrolein

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:

The USEPA recommended acrolein criterion for the protection of aquatic life in freshwater is 3 ug/L ( 4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138248, Acrolein	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253395

Pollutant:

Acrolein

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:

WQ data from the California Integrated Water Quality System (CIWQS) 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 USEPA recommended acrolein criterion for the protection of aquatic life in freshwater is 3 ug/L ( 4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138249	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 and 0 of 1 samples exceeded the guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138249, Aldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253380

Pollutant:

Aldrin

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The aldrin criterion maximum concentration (expressed as a 1-day average) to protect aquatic life in freshwater is 1.5 ug/L. The criterion of 3 ug/L provided in the California Toxics Rule is an instantaneous maximum concentration and was divided by 2 in order to better represent a criterion maximum concentration (CMC) value as specified in footnote (g) of Table (b)(1) of the 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138249, Aldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251783

Pollutant:

Aldrin

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138249, Aldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253381

Pollutant:

Aldrin

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138250	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Alkalinity as CaCO3
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	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 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256932

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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 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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256972

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256832

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256720

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256931

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138250, Alkalinity as CaCO3	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251844

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:

Water Board staff assessed LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Alkalinity as CaCO3.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2019-07-30

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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	138200	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 138200, Allethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256879

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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	153902	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 153902, Aluminum	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

314896

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 153902, Aluminum	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

314788

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	150457	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. A remedial program other than a TMDL has been developed, approved, and is being implemented. This program is expected to result in attainment of the standard. This water segment-pollutant combination was moved off the section 303(d) list during the 2002 listing cycle. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Nine of 173, 0 of 21 and 5 of 133 samples exceeded the objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2448

Pollutant:

Ammonia

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

113

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Six of 113 samples exceed the 30-day average water quality objective and none of 458 samples exceed the one-hour average water quality objective (LACSD, 2006).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Los Angeles RWQCB Basin Plan Amendment 2003: The one-hour average objective is dependent on pH and the presence or absence of early life stages of fish (ELS) but not temperature. The 30-day average objective is dependent on pH, temperature and ELS [Tables 3-1 to 3-3].

Objective/Criterion Reference:

Evaluation Guideline:

USEPA "1999 Update of Ambient Water Quality Criteria for Ammonia".

Guideline Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

Spatial Representation:

Four stations were sampled.

Temporal Representation:

Samples were collected from June 2003 through November 2005. New management practices were begun at the beginning of this period and may have resulted in a change in water quality. Water quality measurements collected before the implementation of management measures were not considered representative of current conditions.

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

94439

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

128

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

1 out of 128 30-day averages exceeded the objective for total ammonia.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Los Angeles Regional Water Quality Control Plan 30-day site specific objective for total ammonia as nitrogen is a function of pH, temperature, and the presence of early life stages. The site specific objective for San Gabriel River Reach 1 (Firestone Blvd to WIllow St) is 2.63 mg N/L.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at monitoring stations Los Coyotes R31 (SG-R31) and Los Coyotes R31B (SG-R31B).

Temporal Representation:

Samples were collected from June 2005 to October 2009.

Environmental Conditions:

QAPP Information:

Samples were collected as part of an NPDES permit requirement. Receiving water data collected to represent the water body as a whole. No QAPP was submitted but an unsigned field manual was.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257260

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:

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:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257222

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:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257113

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:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257021

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:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257058

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

26853

Pollutant:

Ammonia

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Three of 60 samples exceeded the one-hour objective and zero of 245 samples exceeded 30-day average objective for ammonia. All samples analyzed against the acute and chronic criteria had available pH and temperature data which was used to calculate the criteria. The temperature ranged from 19.9 to 30.2 C and the pH ranged from 7.0 to 9.9. Water quality samples were taken and analyzed for ammonia in accordance with the Long Beach Waste Water Reclamation Plant permit monitoring and testing parameters.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan states, "In order to protect aquatic life, ammonia concentrations in inland surface waters characteristic of freshwater shall not exceed the values calculated for the appropriate instream conditions shown in Tables 3-1 to 3-3." The one-hour average objective is dependent on pH and the presence or absence of early life stages of fish (ELS) but not temperature. The 30-day average objective is dependent on pH, temperature and ELS in Tables 3-1 to 3-3. The ammonia objectives and the pH and temperature dependent formula are found in Attachment A of Regional Board Resolution No. 2002-011.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Grab samples were taken and analyzed on a weekly basis from December 2005 to January 2007.

Environmental Conditions:

QAPP Information:

Data was collected in compliance with the sampling and monitoring procedures detailed in Sanitation Districts of Los Angeles County (NPDES No. CA0054119) Monitoring and Reporting Program.

QAPP Information Reference(s):

Long Beach Water Reclamation Plant Monitoring and Reporting Program for NPDES No. CA0054119 (County Sanitation Districts of Los Angeles County)

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2447

Pollutant:

Ammonia

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

An alternative enforceable program is in place that will address ammonia water quality standards exceedances for this reach. In June 1995, the seven water reclamation plants discharging in the San Gabriel River and Santa Clara River watersheds received NPDES permits requirements regarding compliance with the Basin Plan water quality objectives for ammonia. In accordance with these permits, the Los Angeles County Sanitation Districts have been pursuing the addition of nitrification and denitrification facilities at each of these plants to comply with the ammonia objectives. By June 2003, it is expected that these new
facilities will be operational and ammonia will be drastically reduced. Research facility operation shows that the monthly average ammonia concentration will fully comply with the chronic ammonia objective that are expected to be applicable in June 2003.

It is probable that the majority of ammonia discharged to this water body
was contributed by POTWs. Information in the record indicates that the
majority (over 95%) of the ammonia in the Los Angeles River was
contributed by POTWs. It is probable that the contribution in the San
Gabriel River watershed is dominated by contributions from POTWs as
well. Generally, concentrations of ammonia upstream of the treatment
plants is much lower than downstream concentrations (up to an order of
magnitude difference).

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150457, Ammonia	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253554

Pollutant:

Nitrogen, ammonia (Total Ammonia)

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and the results are as follows: 0 of the 21 samples exceeded the water quality threshold for Ammonia as N. Although a total of 25 samples were collected, 4 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:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (658094).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-06-01 to 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138203	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 38, 0 of 38 and 0 of 1 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253455

Pollutant:

Antimony

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Antimony.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253543

Pollutant:

Antimony

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 30 samples exceeded the water quality threshold for Antimony.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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 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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257067

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

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 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253497

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 29 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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257028

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Antimony.

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 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138203, Antimony	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253517

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:

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138205	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 43, 0 of 1 and 0 of 68 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253480

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257435

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Arsenic.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257498

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Arsenic.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257583

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Arsenic.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257355

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Arsenic.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257599

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Arsenic.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253369

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87849

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 68 samples exceeded the criteria of 150 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life. The CTR for arsenic is 150 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138205, Arsenic	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87844

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:

Water Board staff assessed SWAMP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Arsenic.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for arsenic is 33 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	138206	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 38, 0 of 38 and 0 of 1 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253658

Pollutant:

Beryllium

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:

WQ data from the California Integrated Water Quality System (CIWQS) 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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253660

Pollutant:

Beryllium

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:

WQ data from the California Integrated Water Quality System (CIWQS) 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257818

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257782

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253925

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:

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138206, Beryllium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253922

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:

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138246	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Bifenthrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exhibited sediment toxicity. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138246, Bifenthrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87850

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Los Angeles Region (LARWQCB 2004): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. 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:

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 from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138246, Bifenthrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258124

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) 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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	138207	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Cadmium
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 42, 0 of 1 and 0 of 30 samples exceeded the criteria and 0 of 1 sample exceeded the guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

One sample was collected to evaluate sediment toxicity. The sample did not exhibit significant toxicity. The toxicity test included survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 4 Basin Plan.

Objective/Criterion Reference:

Evaluation Guideline:

Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold.

Guideline Reference:

Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87851

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for cadmium is 4.98 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87852

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 30 samples exceeded the hardness adjusted criteria.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Evaluation Guideline to California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metal criterion. If no hardness data were available, a value of 100 mg/L was used. The criterion is 2.2 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258029

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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:

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253930

Pollutant:

Cadmium

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257921

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257990

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

257961

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258143

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Cadmium.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253887

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138207, Cadmium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253932

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138208	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	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 138208, Chlordane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255869

Pollutant:

Chlordane

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Total Chlordane. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138208, Chlordane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253034

Pollutant:

Chlordane

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Total Chlordane.

Data Reference:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138208, Chlordane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252708

Pollutant:

Chlordane

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 chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2019-11-28 and 2019-11-28

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138208, Chlordane	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255822

Pollutant:

Chlordane

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Total Chlordane. Although a total of 19 samples were collected, 19 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 chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138209	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 1, 1 of 87and 4 of 10 samples exceeded the objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251684

Pollutant:

Chloride

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:

WQ data from the MS4 database 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 chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2018-10-20 and 2018-10-20

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258466

Pollutant:

Chloride

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258452

Pollutant:

Chloride

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251685

Pollutant:

Chloride

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 1 of 5 samples exceeded the water quality threshold for Chloride.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2019-07-30

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258431

Pollutant:

Chloride

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chloride.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253788

Pollutant:

Chloride

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 27 samples exceeded the water quality threshold for Chloride.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253784

Pollutant:

Chloride

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 1 of 60 samples exceeded the water quality threshold for Chloride.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258296

Pollutant:

Chloride

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:

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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138209, Chloride	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258504

Pollutant:

Chloride

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chloride.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138210	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Chlorine
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 138210, Chlorine	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253649

Pollutant:

Chlorine

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Chlorine, Total Residual. Although a total of 155 samples were collected, 155 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: Chlorine residual shall not be present in surface water any concentration that causes impairment of beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA recommended chlorine criterion for the protection of aquatic ife in freshwater is 11 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-06-01 to 2019-06-12

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138210, Chlorine	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253629

Pollutant:

Chlorine

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Chlorine, Total Residual. Although a total of 38 samples were collected, 38 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Chlorine residual shall not be present in surface water any concentration that causes impairment of beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA recommended chlorine criterion for the protection of aquatic ife in freshwater is 11 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-06-01 to 2019-04-05

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138211	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Chlorpyrifos
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138211, Chlorpyrifos	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87858

Pollutant:

Chlorpyrifos

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for chlorpyrifos is the median lethal concentration (LC50) of 1.77 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Amweg and Weston, 2007).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138211, Chlorpyrifos	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251802

Pollutant:

Chlorpyrifos

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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 freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).

Guideline Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game

Guideline Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game (with minor corrections to significant figures as described in Beaulaurier et al., 2005).

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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	138255	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Chromium
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 31, 0 of 1, 0 of 30 and 0 of 28 samples exceeded the criteria and 0 of 1 sample exceeded the guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. There is not an associated sediment toxicity. 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:

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258682

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chromium.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258663

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chromium.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258769

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chromium.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87861

Pollutant:

Chromium, hexavalent

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 28 samples exceeded the criteria of 11 ug/L.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The CTR for hexavalent chromium is 11 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87860

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 30 samples exceeded the hardness adjusted criteria.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion. If no hardness data were available, a value of 100 mg/L was used.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87859

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for chromium is 111 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258629

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chromium.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253895

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253943

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:

Water Board staff assessed eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 20 samples exceeded the water quality threshold for Chromium.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253894

Pollutant:

Chromium

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258569

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chromium.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138255, Chromium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):


DECISION ID	138212	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 29 and 0 of 9 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138212, Chromium, hexavalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254152

Pollutant:

Chromium, hexavalent

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 23 samples exceeded the water quality threshold for Chromium VI.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-07-08 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138212, Chromium, hexavalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254106

Pollutant:

Chromium, hexavalent

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Chromium VI.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2012-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138212, Chromium, hexavalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254155

Pollutant:

Chromium, hexavalent

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Chromium VI.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2014-01-14 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138212, Chromium, hexavalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

251908

Pollutant:

Chromium, hexavalent

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138212, Chromium, hexavalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254085

Pollutant:

Chromium, hexavalent

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:

The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-07-01

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138213	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 23 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138213, Chromium, trivalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254241

Pollutant:

Chromium, trivalent

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 hardness dependent. The criterion when calculated 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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2016-01-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138213, Chromium, trivalent	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254240

Pollutant:

Chromium, trivalent

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2016-01-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138214	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Copper
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 1 of 154, 0 of 1 and 0 of 82 samples exceeded the criteria for copper in water and 0 of 1 sample exceeded the guideline for copper in sediment and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

259144

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Copper.

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:

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258933

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Copper.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258934

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Copper.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

258981

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Copper.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

259328

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Copper.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252168

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:

Water Board staff assessed LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Copper.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2017-11-20 and 2019-07-30

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254269

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:

Water Board staff assessed eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 1 of 32 samples exceeded the water quality threshold for Copper.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254200

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

112

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 112 samples exceeded the water quality threshold for Copper.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-09-16

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254224

Pollutant:

Copper

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87862

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for copper is 149 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138214, Copper	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87863

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

none of the 82 samples exceeded the hardness adjusted criteria of 9.0 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metal criterion. If no hardness data were available, a value of 100 mg/L was used.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	138215	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. 3 lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 4 of 107 samples exceeded the California Toxics Rule criterion for the protection of aquatic life in water does not exceed the allowable frequency listed in Table 3.1 for warm freshwater habitat. 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:

Line of Evidence (LOE) for Decision ID 138215, Cyanide	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254116

Pollutant:

Cyanide

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 2 of 71 samples exceeded the water quality threshold for Cyanide.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The cyanide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138215, Cyanide	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254089

Pollutant:

Cyanide

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The cyanide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138215, Cyanide	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252353

Pollutant:

Cyanide

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and the results are as follows: 2 of the 7 samples exceeded the water quality threshold for Cyanide. Although a total of 9 samples were collected, 2 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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The cyanide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LSGR-GR1).

Temporal Representation:

Data for this waterbody was collected over the date range 2016-02-18 to 2019-12-20

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):


DECISION ID	138252	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Cyfluthrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138252, Cyfluthrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87864

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138252, Cyfluthrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

259444

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	138254	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Cyhalothrin, Lambda
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138254, Cyhalothrin, Lambda	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87865

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138254, Cyhalothrin, Lambda	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262537

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

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	138247	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Cypermethrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138247, Cypermethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

259230

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138247, Cypermethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87866

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	138253	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Deltamethrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138253, Deltamethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87870

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138253, Deltamethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

259824

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	138217	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Diazinon
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:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 2 lines of evidence is available in the administrative record to assess this pollutant. 0 of 52 samples exceeded the criteria. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 52 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138217, Diazinon	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87871

Pollutant:

Diazinon

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for diazinon is the median lethal concentration (LC50) of 11 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 11 ug/g is the geometric mean of LC50 values for diazinon 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138217, Diazinon	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254382

Pollutant:

Diazinon

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Diazinon.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 freshwater chronic value for diazinon is 0.10 ug/L (4 day average)(Finlayson, 2004).

Guideline Reference:

Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-06 and 2019-10-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138217, Diazinon	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254430

Pollutant:

Diazinon

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 38 samples exceeded the water quality threshold for Diazinon.

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 freshwater chronic value for diazinon is 0.10 ug/L (4 day average)(Finlayson, 2004).

Guideline Reference:

Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-06 and 2020-10-12

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138218	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Dieldrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 3 lines of evidence are available in the administrative record to assess this pollutant. 0 of 25 samples exceeded the criterion for dieldrin in water. 0 of 1 sample exceeded the criterion for dieldrin in water. 0 of 1 sample exceeded the guideline for dieldrin in sediment. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 and 0 of 1 samples exceeded the criterion for dieldrin in water and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 0 of 1 sample exceeded the guideline for dieldrin in sediment and this sample size is insufficient to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138218, Dieldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138218, Dieldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254503

Pollutant:

Dieldrin

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138218, Dieldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252244

Pollutant:

Dieldrin

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138218, Dieldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87872

Pollutant:

Dieldrin

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for dieldrin is 61.8 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138218, Dieldrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254592

Pollutant:

Dieldrin

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138219	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138219, Endosulfan sulfate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254609

Pollutant:

Endosulfan sulfate

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 USEPA National Recommended Water Quality Criteria toxicity threshold for endosulfan sulfate for freshwater aquatic life protection is 0.056 ug/l (24 hour average)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138219, Endosulfan sulfate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254655

Pollutant:

Endosulfan sulfate

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 USEPA National Recommended Water Quality Criteria toxicity threshold for endosulfan sulfate for freshwater aquatic life protection is 0.056 ug/l (24 hour average)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138220	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Endrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List for pollutants in water under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. 1 line of evidence is available in the administrative record to assess this waterbody for Endrin in water. 0 of the 25 samples exceeded the criteria. This pollutant is also being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this waterbody for Endrin in sediment. 0 of the 1 sample exceeded the guideline. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the criteria for Endrin in water and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 0 of 1 sample exceeded the guideline for Endrin in sediment and this sample size is insufficient to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138220, Endrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254869

Pollutant:

Endrin

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138220, Endrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254808

Pollutant:

Endrin

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138220, Endrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87873

Pollutant:

Endrin

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for endrin is 207 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	138257	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Esfenvalerate/Fenvalerate
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138257, Esfenvalerate/Fenvalerate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

261130

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138257, Esfenvalerate/Fenvalerate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87875

Pollutant:

Esfenvalerate/Fenvalerate

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for esfenvalerate/fenvalerate is the median lethal concentration (LC50) of 1.5 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.5 ug/g is the geometric mean of LC50 values for esfenvalerate/fenvalerate from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	138256	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Fenpropathrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 138256, Fenpropathrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87876

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138256, Fenpropathrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

261525

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

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	138201	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 138201, Fenvalerate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

261767

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138221	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Glyphosate
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 138221, Glyphosate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252111

Pollutant:

Glyphosate

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 evaluation guideline for glyphosate is the USEPA Aquatic Life Benchmark of 11,900 ug/L for a vascular plant (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138222	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	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 138222, Heptachlor	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254962

Pollutant:

Heptachlor

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor. Although a total of 19 samples were collected, 19 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 heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138222, Heptachlor	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252207

Pollutant:

Heptachlor

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138222, Heptachlor	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254985

Pollutant:

Heptachlor

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the 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 heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138223	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	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 138223, Heptachlor epoxide	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254840

Pollutant:

Heptachlor epoxide

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor Epoxide. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The heptachlor epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138223, Heptachlor epoxide	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254841

Pollutant:

Heptachlor epoxide

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor Epoxide. Although a total of 19 samples were collected, 19 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The heptachlor epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138224	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Iron
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 5, 0 of 5 and 0 of 28 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87877

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

One of the 28 samples exceeded the criteria of 1,000 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

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 aquatic organisms from chronic exposures (expressed as 4-day average concentration) in freshwater. The evaluation guideline for iron is 1,000 ug/L to protect warm freshwater habitat.

Guideline Reference:

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262637

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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:

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262337

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262621

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262287

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262244

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262298

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262355

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262434

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262338

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138224, Iron	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262323

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Iron.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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	138226	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Lead
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. 4 lines of evidence are available in the administrative record to assess this pollutant. 0 of 43 sample exceeded the criteria for lead in water. 0 of 30 samples exceeded the criteria for lead in water. 0 of 1 sample exceeded the criteria for lead in water. 0 of 1 sample exceeded the guideline for lead in sediment. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 42, 0 of 1 and 0 of 30 samples exceeded the criteria and 0 of 1 sample exceeded the guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262544

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Lead.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262597

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Lead.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262960

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Lead.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255135

Pollutant:

Lead

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87878

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for lead is 128 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87879

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 30 samples exceeded the criteria of 2.5 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

262618

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Lead.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263052

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Lead.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254698

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255023

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138226, Lead	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252630

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2018-03-23 and 2018-03-23

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138227	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
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 sections 3.1 and 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 25 and 0 of 1 exceed the criteria and 0 of 1 sample exceeded the GUIDELINE and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138227, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254769

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

The gamma-BHC (Lindane, gamma-HCH) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138227, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252140

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The gamma-BHC (Lindane, gamma-HCH) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138227, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87880

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for Lindane (gamma-HCH) is 4.99 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138227, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254772

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The gamma-BHC (Lindane, gamma-HCH) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138228	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Malathion
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 138228, Malathion	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252507

Pollutant:

Malathion

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.028 ug/L (UC Davis Aquatic Life Criteria).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	149821	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Mercury
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. 2 lines of evidence are available in the administrative record to assess this pollutant. 0 of 35 sample exceeded the criteria. 0 of 37 sample exceeded the criteria. 0 of 21 sample exceeded the criteria. 0 of 69 samples exceeded the criteria. 0 of 1 sample exceeded the guideline. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 35, 0 of 37, 0 of 21, 0 of 69 samples exceeded the criteria and 0 of 1 sample exceeded the guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255099

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:

Water Board staff assessed eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 7 samples exceeded the water quality threshold for Mercury.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-04-05

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87881

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for mercury is 1.06 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87882

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 69 samples exceeded the criteria of 0.77 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

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

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263336

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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:

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263355

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263277

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252658

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:

Water Board staff assessed LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 16 samples exceeded the water quality threshold for Mercury.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2019-12-20

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255076

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-01-02

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263391

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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:

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263293

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255078

Pollutant:

Mercury

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:

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263329

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263331

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255075

Pollutant:

Mercury

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:

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263460

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263461

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 149821, Mercury	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263279

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Mercury.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138229	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 and 0 of 2 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138229, Naphthalene	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255043

Pollutant:

Naphthalene

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:

The Water Quality Control Plan for the Los Angeles Region states that: 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 USEPA recommended naphthalene criterion for the protection of freshwater aquatic life is 620 ug/l. (EPA 440/5-80-059)

Guideline Reference:

Ambient Water Quality Criteria for Naphthalene

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138229, Naphthalene	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255363

Pollutant:

Naphthalene

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:

WQ data from the California Integrated Water Quality System (CIWQS) 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 USEPA recommended naphthalene criterion for the protection of freshwater aquatic life is 620 ug/l. (EPA 440/5-80-059)

Guideline Reference:

Ambient Water Quality Criteria for Naphthalene

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138229, Naphthalene	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252560

Pollutant:

Naphthalene

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Naphthalene.

Data Reference:

WQ data from the MS4 database 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 USEPA recommended naphthalene criterion for the protection of freshwater aquatic life is 620 ug/l. (EPA 440/5-80-059)

Guideline Reference:

Ambient Water Quality Criteria for Naphthalene

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2017-07-20

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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	138230	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Nickel
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 42, 0 of 1 and and 0 of 68 samples exceeded the criteria for nickel in water and 0 of 1 sample exceeded the guideline for nickel in sedimentand this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263922

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nickel.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

264086

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nickel.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255281

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255344

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255299

Pollutant:

Nickel

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263776

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nickel.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263996

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nickel.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

263778

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nickel.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87884

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for nickel is 48.6 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138230, Nickel	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87885

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 68 samples exceeded the criteria of 52 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	149822	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 144 and 0 of 5 samples exceeded the OBJECTIVE and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302356

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as N.

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:

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302602

Pollutant:

Nitrogen, Nitrate

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 32 samples exceeded the water quality threshold for Nitrate as N.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302433

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as N.

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:

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302360

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as N.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302440

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as N.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302431

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as N.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149822, Nitrogen, Nitrate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302619

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

112

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-09-16

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138233	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 52 samples exceeded the GUIDELINE and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138233, Organophosphate Pesticides	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255527

Pollutant:

Organophosphate Pesticides

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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 the protection of aquatic life from the additive effects of the organophosphate pesticides chlorpyrifos and diazinon is one toxic unit equivalent. A toxic unit equivalent is equal to the sum of chlorpyrifos and diazinon from a single sample, each having their reported concentration divided their respective evaluation guideline prior to being summed. If this results in a value greater than one, the sample is considered to be in exceedance of the water quality standard. (Bailey et al., 1997).

Guideline Reference:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-06 and 2020-10-12

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138233, Organophosphate Pesticides	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252836

Pollutant:

Organophosphate Pesticides

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138233, Organophosphate Pesticides	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255614

Pollutant:

Organophosphate Pesticides

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:

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:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-06 and 2019-10-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	151913	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Oxygen, Dissolved
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:	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. Eight lines of evidence are available in the administrative record to assess this pollutant. 1 of 358 samples exceeded the OBJECTIVE. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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. 1 of 358 samples exceeded the OBJECTIVE and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

307962

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:

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

307811

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

308033

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

308155

Pollutant:

Oxygen, Dissolved

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

307991

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.

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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

307989

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 San Gabriel River Reach 1 (Estuary to Firestone) 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:

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

Line of Evidence (LOE) for Decision ID 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87886

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

209

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of 209 samples exceeded the objective.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved Oxygen Water Quality Objective of all surface waters designated as Warm Fresh Water Aquatic Habitat shall not be depressed below 5 mg/l.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the LC-R31, LCR-31B, and LC-R4.

Temporal Representation:

Samples were collected approximately once a month from July 2005 to November 2009.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 151913, Oxygen, Dissolved	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

308102

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

112

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) 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:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-09-16

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138237	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	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 138237, PCBs (Polychlorinated biphenyls)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255701

Pollutant:

PCBs (Polychlorinated biphenyls)

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for PCBs (Polychlorinated biphenyls). Although a total of 14 samples were collected, 14 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The PCB, total aroclors criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.014 ug/L. This value corresponds to the sum of aroclors 1242, 1254, 1221, 1232, 1248, 1260, and 1016 (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138237, PCBs (Polychlorinated biphenyls)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255636

Pollutant:

PCBs (Polychlorinated biphenyls)

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for PCBs (Polychlorinated biphenyls). Although a total of 5 samples were collected, 5 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2015-01-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138235	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 and 0 of 1 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138235, Pentachlorophenol (PCP)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255541

Pollutant:

Pentachlorophenol (PCP)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pentachlorophenol criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is pH dependent. The criterion using a default pH value of 7.8 (when pH data is not present) is 15 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138235, Pentachlorophenol (PCP)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255497

Pollutant:

Pentachlorophenol (PCP)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138235, Pentachlorophenol (PCP)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252741

Pollutant:

Pentachlorophenol (PCP)

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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	138258	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Permethrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence are necessary to assess listing status. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the CRITERIA. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the CRITERIA and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 138258, Permethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

264760

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138258, Permethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87887

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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 from 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 for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	138204	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 138204, Prallethrin	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265660

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prallethrin.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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	138245	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 138245, Pyrethroids	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

265739

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

Data for this waterbody were collected over the date range 2016-06-23 to 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138238	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Selenium
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 45, 0 of 38, 0 of 8 and 0 of 30 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252701

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:

Water Board staff assessed LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 3 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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2017-11-20 and 2018-05-22

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266088

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266351

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266257

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266041

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266218

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255693

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266181

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Selenium.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266200

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255434

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87889

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 30 samples exceeded the criteria of 5 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The CTR for selenium is 5.0 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266153

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Selenium.

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:

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253029

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2017-11-20 and 2018-05-22

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255387

Pollutant:

Selenium

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:

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255696

Pollutant:

Selenium

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266154

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Selenium.

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:

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138238, Selenium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266085

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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	138239	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Silver
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 38, 0 of 1 and 0 of 68 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138239, Silver	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266419

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 San Gabriel River Reach 1 (Estuary to Firestone) 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138239, Silver	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256003

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:

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138239, Silver	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256000

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:

Data Reference:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138239, Silver	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255999

Pollutant:

Silver

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138239, Silver	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87890

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 68 samples exceeded the hardness adjusted criteria of 3.4 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion maximum concentrations for silver to protect aquatic life in freshwater (1-hour average). The silver criterion is 3.4 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	138202	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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 138202, T-Fluvalinate	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

266430

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for T-Fluvalinate.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138241	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 38, 0 of 38 and 0 of 1 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256012

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:

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267521

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

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 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256011

Pollutant:

Thallium

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:

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267561

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 San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Thallium.

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 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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255991

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:

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138241, Thallium	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

255905

Pollutant:

Thallium

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:

WQ data from the California Integrated Water Quality System (CIWQS) 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 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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138242	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	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 138242, Toxaphene	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256228

Pollutant:

Toxaphene

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Toxaphene. Although a total of 19 samples were collected, 19 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138242, Toxaphene	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256129

Pollutant:

Toxaphene

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Toxaphene. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138243	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the 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. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 144 and 0 of 5 samples exceeded the objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267871

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.

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:

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

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 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267908

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256294

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

112

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2020-09-16

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256266

Pollutant:

Turbidity

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-06-01 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267889

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.

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:

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267967

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.

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: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138243, Turbidity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

267969

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138244	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Zinc
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 44, 0 of 1 and 0 of 30 samples exceeded the criteria for zinc in water and 0 of 1 samples exceeded the guideline for zinc in sediment and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256190

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87897

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:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for zinc is 459 mg/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87904

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

One of the 30 samples exceeded the criteria of 120 ug/L.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from San Gabriel River Reach 1 (Estuary to Firestone) from location LC also called SG at three sublocations: R4, R31, and R31B.

Temporal Representation:

Samples were collected monthly from June 2006 through May of 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256160

Pollutant:

Zinc

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

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: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2013-06-14 and 2013-06-14

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

253074

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

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: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2018-03-23 and 2019-07-30

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

256177

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: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2019-10-07

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

268412

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Zinc.

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SMC04670 (SGMR04670).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

268398

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Zinc.

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: SMC08766_SGRRMP (SGMR08766).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

268463

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Zinc.

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: SMC03390 (SGMR03390).

Temporal Representation:

The samples were collected between the dates of 2017-05-03 and 2017-05-03

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 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

268428

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Zinc.

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: SMC09534_SGRRMP (SGMR09534).

Temporal Representation:

The samples were collected between the dates of 2018-07-10 and 2018-07-10

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 138244, Zinc	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

268065

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:

Water Board staff assessed San Gabriel River Regional Monitoring Program data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Zinc.

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: 405M10600_SGRRMP (SGMR10600).

Temporal Representation:

The samples were collected between the dates of 2016-06-23 and 2016-06-23

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.


DECISION ID	138216	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	alpha-Endosulfan (Endosulfan 1)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138216, alpha-Endosulfan (Endosulfan 1)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254649

Pollutant:

alpha-Endosulfan (Endosulfan 1)

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:

The endosulfan I (alpha-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138216, alpha-Endosulfan (Endosulfan 1)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254648

Pollutant:

alpha-Endosulfan (Endosulfan 1)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan I (alpha-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	138234	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	beta-Endosulfan (Endosulfan 2)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138234, beta-Endosulfan (Endosulfan 2)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254350

Pollutant:

beta-Endosulfan (Endosulfan 2)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan II (beta-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 138234, beta-Endosulfan (Endosulfan 2)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254379

Pollutant:

beta-Endosulfan (Endosulfan 2)

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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan II (beta-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

The samples were collected between the dates of 2011-07-11 and 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program


DECISION ID	149820	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision:	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
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 one line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 3 lines of evidence are available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. 0 of 0 samples exceeded the criteria. 2 of 2 samples exceeded the criteria. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 0 and 2 of 2 samples exceeded the criteria and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 0 of 1 sample exceeded the guideline for pollutants in sediment and this sample size is insufficient to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254073

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDT(p,p'). Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the 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:

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658094 (RSW-001).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2016-01-11

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252219

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1-HR (NA).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the California Integrated Water Quality System (CIWQS) assembled for the 2024 Integrated Report in Region 4.

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

254142

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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 eSMR_Los Coyotes WRP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDT(p,p'). Although a total of 19 samples were collected, 19 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 DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 658095 (RSW-002).

Temporal Representation:

Data for this waterbody were collected over the date range 2011-07-11 to 2020-07-09

Environmental Conditions:

QAPP Information:

Los Angeles County Sanitation Districts. 2020. Los Angeles County Sanitation Districts Receiving Water Monitoring Program.

QAPP Information Reference(s):

Los Angeles County Sanitation Districts Receiving Water Monitoring Program

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252196

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the dates of 2016-02-18 and 2016-02-18

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87869

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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 SWAMP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDT.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for sum of DDT is 62.9 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 149820, DDT (Dichlorodiphenyltrichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):


DECISION ID	138232	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Oil and Grease
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
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. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 13 of 13 samples exceed the objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 138232, Oil and Grease	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

252774

Pollutant:

Oil and Grease

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 LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and the results are as follows: 13 of the 13 samples exceeded the water quality threshold for OilandGrease; HEM. Although a total of 14 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:

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Waters shall not contain oils, greases, waxes or other materials in concentrations that result in a visible film or coating on the surface of the water or on objects in the water, that cause nuisance, or that otherwise adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

According to the USEPA Quality Criteria for Water (Gold Book), concentrations of oil at 0.001 mg/L can harm aquatic life. (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 (LSGR-GR1).

Temporal Representation:

Data for this waterbody was collected over the date range 2016-02-17 to 2019-12-20

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.


DECISION ID	150325	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Indicator Bacteria
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	See TMDL documentation
TMDL Name:	San Gabriel River Coliform (45)
TMDL Project Code:	391
Date TMDL Approved by USEPA:	06/14/2016
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 and 3.11 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Because a statistically sufficient number of geomean samples were not available, attainment of the bacteria objective was determined based only on the STV per the situation-specific weight of evidence approach outlined in Section 3.11 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 12 of 22 samples exceeded the statistical threshold value for E. coli and these exceed the allowable frequency listed in Table 3.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 150325, Indicator Bacteria	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

302968

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed LA County MS4 data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and the results are as follows: 12 of the 22 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): LSGR-GR1 (San Gabriel River above Spring Street).

Temporal Representation:

The samples were collected between the days of 2016-02-17 and 2019-12-18 .

Environmental Conditions:

QAPP Information:

Municipal Separate Storm Sewer System (MS4)

QAPP Information Reference(s):

Placeholder reference pre-2006 303(d)

Line of Evidence (LOE) for Decision ID 150325, Indicator Bacteria	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

4146

Pollutant:

Coliform Bacteria

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150325, Indicator Bacteria	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87874

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Nine of the 55 samples exceeded the E. coli objective.

Data Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The E. coli density shall not exceed 235/100 ml. (Water Quality Control Plan for the Los Angeles Region).

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002

Spatial Representation:

The samples were collected at Los Coyotes Station RSW-002 (R-4). Site LC-R31 was added. Mapping change requested sites LB-RA2 and LC-R9W are within the San Gabriel River Estuary

Temporal Representation:

The samples were collected once a week from June 2005 to December 2006 and then once a month from 2007 to 2010.

Environmental Conditions:

QAPP Information:

The samples were collected under the San Jose Creek Laboratory sample collection procedures. Dec 28, 2010.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150325, Indicator Bacteria	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

25294

Pollutant:

Indicator Bacteria

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

386

Number of Exceedances:

Data and Information Type:

Other Agencies/Organizations provided monitoring data

Data Used to Assess Water Quality:

55 of 386 samples exceeded the Basin Plan single sample water quality objectives for indicator bacteria in fresh water and 28 of 82 samples exceeded the Basin Plan geometric mean water quality objective. Water quality samples were taken and analyzed for indicator bacteria in accordance with the Sanitation Districts of Los Angeles County permit monitoring and testing parameters.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan bacteria objectives state that to protect water contact recreation in fresh waters individual samples shall not exceed the following limits: fecal coliform density shall not exceed 400/100 ml; and E. coli density shall not exceed 235/100 ml. The bacteria objectives also establish that the geometric means of individual samples shall not exceed the following limits: the fecal coliform density shall not exceed 200/100 ml; and the E. coli density shall not exceed 126/100 ml, as a geometric mean. The bacteria objectives are found in Attachment A of Regional Board Resolution No. 2001-018.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The Sanitation Districts of Los Angeles County conducted sampling in San Gabriel River Reach 1 in the following receiving water monitoring stations: station RA2 located downstream of the confluence of the eastern and western low flow channel; station R31 located 100 feet upstream of the Los Coyotes discharge point; station R4 located at Artesia Boulevard, downstream of the Los Coyotes discharge point; and station R9W located at at the downstream end of the pavement lining (near Atherton Street) in the western low flow channel.

Temporal Representation:

Grab samples were taken and analyzed on a weekly and monthly basis from June 2004 to February 2007

Environmental Conditions:

QAPP Information:

Data was collected in compliance with the sampling and monitoring procedures detailed in Sanitation Districts of Los Angeles County (NPDES No. CA0054119) Monitoring and Reporting Program.

QAPP Information Reference(s):

Long Beach Water Reclamation Plant Monitoring and Reporting Program for NPDES No. CA0054119 (County Sanitation Districts of Los Angeles County)


DECISION ID	68159	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Abnormal Fish Histology (Lesions)
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This pollutant is being considered for delisting under sections 4.8 of the Listing Policy. Under section 4.8 delisting is appropriate when documented adverse biological responses are not associated with water or sediment numeric pollutant specific evaluation guidelines. One line of evidence is available in the administrative record to assess this pollutant. Based on section 4.8, adverse biological responses have been documented in fish taken from the site. Although a small portion of the fish collected exhibited impacts from toxicity, the majority of the fish samples collected from the San Gabriel River and its tributaries were victims of infectious disease. Therefore there is insufficient information to conclude that the documented adverse biological responses are associated with specific pollutant(s). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of removing this water segment-pollutant combination from the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The sediment quality guideline used complies, with the requirements of section 6.1.3 of the Policy. 2. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 3. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 4. The majority of the fish collected showed adverse biological responses are associated with infectious disease and not due to pollutant caused toxicity. 5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met

Regional Board Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

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 68159, Abnormal Fish Histology (Lesions)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2452

Pollutant:

Abnormal Fish Histology (Lesions)

LOE Subgroup:

Adverse Biological Responses

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

San Gabriel River Tidal Prism at Confluence of Coyote Creek (LACSD, 2004b).

A total of 21 tilapia (Tilapia sp.) were collected at this site. Extensive inflammation of nerve tissue was observed. The cells in question were associated with a swollen feature of the nerve indicating damage. The frequency of this abnormality was 33%. Gill necrosis was observed in 3 of the animals studied. The frequency for this lesion was 14%. Skin necrosis was found in 2 of the 21 animals observed. One gut parasite was found and appeared to be a tapeworm.

San Gabriel River Tidal Prism at College Park Drive (LACSD, 2004b).

A total of 30 tilapia (Tilapia sp.) and 1 white croaker (Genyonemus lineatus) were examined from this site. Histopathologic examination revealed severe inflammation in the stomach. The white croaker showed mild inflammation in the liver and inflammatory response in the wall of the heart. In the 30 tilapia, fairly consistent nerve inflammation were observed. The frequency of this lesion was 30%. Inflammation of the liver were also observed. The frequency for this change was 13%. A large skin lesion was observed on one tilapia. One fish showed a parasite within the gut.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological response in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropriate methods as specified by the State or Regional Board.

Objective/Criterion Reference:

Evaluation Guideline:

With a prior knowledge of normal fish anatomy, the investigators used histological analysis to detect alterations in tissues and organs caused by exposure to toxicants. When the concentration of a toxicant is sufficient to result only in cellular injury, but not in death of the cells, sublethal (adaptive) changes may be observed in affected cells.

A combination of the necropsy-based approach and the histological condition index was used in this study. Alterations from the expected normal gross anatomy and microscopic anatomy of resident fishes, fathead minnow (Pimephales promelas), goldfish (Cyprinus carpio), white croaker (Genyonemus lineatus) mosquito fish (Gambusia affinis), and tilapia (Tilapia sp.) were included in the investigation. Lesions were compared to reference populations.

Guideline Reference:

Spatial Representation:

Fish were collected from four sites in the lower San Gabriel River watershed. The sites included Coyote Creek above and below the Long Beach wastewater treatment plant outfall, the San Gabriel River at the confluence of Coyote Creek, and from the tidal prism at College Park Drive.

Temporal Representation:

Samples were collected between 1992 and 1993.

Environmental Conditions:

QAPP Information:

Quality Assurance and methods well described in the report: "Toxicity study of the Santa Clara, San Gabriel River, and Calleguas Creek" (Bailey et al., 1996 in LACSD, 2004b).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68159, Abnormal Fish Histology (Lesions)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2451

Pollutant:

Abnormal Fish Histology (Lesions)

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

This evaluation of data came from the report: "Toxicity study of the Santa Clara, San Gabriel River, and Calleguas Creek" (Bailey et al., 1996 in LACSD, 2004b).Toxicity Identification Evaluations were completed and it was suggested that diazinon, chlorpyrifos, and ammonia were the cause of the toxicity. Studies of upstream and downstream sites in the San Gabriel River Tidal Prism revealed toxicity. Inflammatory lesions were prevalent at about 30% in fish from both sites. Gill toxicity reactions were seen at equal frequency. In the upper site, only two fish showed extensive tubular epithelial hyalinization of kidney while 5 of their counterparts from the lower site were positive for the same lesion. In addition, the lesions had advanced in the downstream affected fish to the point at which tubular deposits of calcium were prominent in two fish. Heart ventricle also showed mineralization, a likely sequel to systemic infection. Skin necrosis, likely a direct result of toxicity in the water column characterized two of the 30 fish at the lower site.

The analysis of fish collected from the San Gabriel River and its tributaries suggests that a sizeable portion of the individuals are victims of infectious disease and a smaller portion reveal signs of toxicity. These are not healthy fish and their tissue conditions do not resemble those of fishes from reference habitats previously investigated by this group.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):


DECISION ID	69447	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Excess Algal Growth
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.7 of the Listing Policy. Under section 4.7 a single line of evidence is necessary to assess listing status. It is not known if the algae information is backed by pollutant data. Algae should not be placed on the section 303(d) list because it is not a pollutant or toxicity (section 2 of the Listing Policy). One line of evidence is available in the administrative record to assess this pollutant. Two of the samples were judged to exceed a subjective algae ranking guideline. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. Two of 4 samples exceeded the Subjective algae guideline and this does not exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 2. Excess algae growth information should not be placed on the section 303(d) list because it is not a pollutant or toxicity (section 2 of the Listing Policy). 3. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

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 69447, Excess Algal Growth	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2453

Pollutant:

Excess Algal Growth

LOE Subgroup:

Pollutant-Nuisance

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Four observations with 2 of the observations judged to be not supporting beneficial uses (SWRCB, 2003).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growth causes nuisance or adversely affects beneficial uses.

Objective/Criterion Reference:

Evaluation Guideline:

The presence of algae in the water segment was used as the guideline. The rankings were subjective and assigned to water bodies by one person for consistency.

Guideline Reference:

Spatial Representation:

One sampling location.

Temporal Representation:

Observations made between 1992 and 1995. Samples taken in different seasons and no greater than two time within one year.

Environmental Conditions:

QAPP Information:

No QA information provided.

QAPP Information Reference(s):


DECISION ID	68767	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Toxicity
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Applicable WQS attained; reason for recovery unspecified
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. 2 lines of evidence are available in the administrative record to assess this pollutant. 0 of the 1 samples exceeded the GUIDELINE. 10 of the 142 samples exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from 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. 0 of 1 and 10 of 142 samples exceeded the OBJECTIVE and this does not exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant 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 68767, Toxicity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87896

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The sample was collected at station 405SGRA2x.

Temporal Representation:

The samples were collected in May 2008.

Environmental Conditions:

QAPP Information:

All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68767, Toxicity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2449

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Numeric data generated from a total of 36 samples (12 samples per sampling stations) from Reach 1 stations R-1-3-1, R-9, and R-9 W respectively, taken from 6/2003 to 5/2004 on a monthly interval. No adverse effects (100 percent survival and growth) were observed in all toxicity results from all three sampling stations (LACSD, 2004b).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Narrative Toxicity Basin Plan WQO is applicable to the protection of aquatic life BUs.

Objective/Criterion Reference:

Evaluation Guideline:

No observed effect concentration (NOEC) is the highest tested concentration of toxicant to which organisms are exposed in a full life-cycle or partial life-cycle (shot-term) test that causes no observable adverse effect on the test organisms. The guideline is used and recommended to determine the highest concentration of toxicant at which the values of the observed responses are not statistically significantly different from the control.

Guideline Reference:

Spatial Representation:

Three (3) sample sites sampled from 6/2003 through 5/2004 at a monthly interval. Station R-3-1 is located towards the upstream end of Reach 1, upstream of the Los Coyotes Water Reclamation Plant (WRP). Receiving water station R-4 is located downstream of the discharge of the Los Coyotes WRP. Receiving water station R-9W is located at the lower end of Reach 1, just upstream of the San Gabriel River Estuary. All sampling stations are all located in Reach 1 of the San Gabriel River.

Temporal Representation:

Thirty-six (36) samples where taken from 6/2003 through 5/2004 at a monthly interval from three sampling stations within Reach 1 of the San Gabriel River.

Environmental Conditions:

The submitted toxicity results are from 2003-04. In June 2003, the LA County Sanitation Districts completed conversion of water reclamation plants in the San Gabriel River watershed to nitrification/denitrification (NDN) mode.

QAPP Information:

Evaluation of Analytes and QA/QC Specifications for Monitoring Program (Woodward-Clyde, 1996) Los Angeles County Department of Public Works.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68767, Toxicity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

2450

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Numeric toxicity results generated from a total of ten samples none of which were found to be toxic. This was a collaborative toxicity study conducted by the U.S. EPA and the Districts in August through October 2003. The study generated a total of 16 samples taken for Reach 1. Six (6) samples were taken in August 2003 (2 from R-3-1, 2 from R-4, and 2 from R-9W), 4 samples were taken in September 2003 (2 from R-3- 1, 2 from R-4, and 1 from R-9W) and 6 samples were taken in October 2003 (2 from R-3-1, 2 from R-4, and 2 from R-9W). The August 2003, sampling results (6 samples) were excluded from analysis due a short-term operational upset that occurred while sampling was being carried out in the San Jose Creek WRP located within Reach 1 (LACSD, 2004b).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin plan narrative toxicity WQO.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Data for Various Pollutants in Various Water Bodies in Sanitation Districts of Los Angeles County, 2005-2010.

Spatial Representation:

Three (3) sample sites sampled from 8/2003 through 10/2003 at a monthly interval. Station R-3-1 is located towards the upstream end of Reach 1, upstream of the Los Coyotes Water Reclamation Plant (WRP). Receiving water station R-4 is located downstream of the discharge of the Los Coyotes WRP. Receiving water station R-9W is located at the lower end of Reach 1, just upstream of the San Gabriel River Estuary. All sampling stations are all located in Reach 1 of the San Gabriel River.

Temporal Representation:

A total of 16 samples were taken, six (6) samples were taken in August 2003 (2 from R-3-1, 2 from R-4, and 2 from R-9W), 4 samples were taken in September 2003 (2 from R-3- 1, 2 from R-4, and 1 from R-9W) and 6 samples were taken in October 2003 (2 from R-3-1, 2 from R-4, and 2 from R-9W).

Environmental Conditions:

Data is one year old. The August 2003, sampling results (6 samples) were excluded from analysis due a short-term operational upset that occurred while sampling was being carried out in the San Jose Creek WRP located within Reach 1.

QAPP Information:

Evaluation of Analytes and QA/QC Specifications for Monitoring Program (Woodward-Clyde, 1996) Los Angeles County Department of Public Works.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68767, Toxicity	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

94440

Pollutant:

Toxicity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Ten of the 96 samples exceeded the evaluation guideline. Toxicity data was not reported with a control, therefore anything reported as <100 (chronic) or <100% survival (acute) was considered an exceedance.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Toxic pollutants shall not be present at levels that will bioaccumulate in aquatic life to levels which are harmful to aquatic life or human health. No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. There shall be no bioaccumulation of pesticide concentrations found in bottom sediments or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Statistically significant difference from control using a t-test or other valid statistical tests.

Guideline Reference:

Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013

Spatial Representation:

The samples were collected at Long Beach Station Los Coyotes Station RSW-002 (R-4 and R-5). Stations LC-R31 and LC-R31B were added. mapping change requested.

Temporal Representation:

Samples were collected quarterly from June 2005 through October 2009.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	98572	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	DDD (Dichlorodiphenyldichloroethane)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 98572, DDD (Dichlorodiphenyldichloroethane)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87867

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

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 SWAMP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDD.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for sum of DDD is 28.0 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	98630	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	DDE (Dichlorodiphenyldichloroethylene)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 98630, DDE (Dichlorodiphenyldichloroethylene)	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87868

Pollutant:

DDE (Dichlorodiphenyldichloroethylene)

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 SWAMP data for San Gabriel River Reach 1 (Estuary to Firestone) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDE.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for sum of DDE is 31.3 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for San Gabriel River Reach 1 (Estuary to Firestone) was collected at 1 monitoring site [ San Gabriel River RA-2 station (405SGRA2x).]

Temporal Representation:

Data was collected on a single day 5/20/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

SWAMP data collected before September 2008 followed the QAMP (2002).

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	98633	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

Pollutant:	Methyl Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. 1 line of evidence is available in the administrative record to assess this pollutant. 0 of 1 sample exceeded the GUIDELINE. Based on the readily available data and information, the weight of evidence indicates that there is INSUFFICIENT justification FOR placing this water segment-pollutant combination on the 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. 0 of 1 sample exceeded the GUIDELINE and this sample size is INSUFFICIENT to determine beneficial use support, with the power and confidence of the Listing Policy. There is not an associated sediment toxicity data as required by Section 3.6 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 98633, Methyl Parathion	Region 4
San Gabriel River Reach 1 (Estuary to Firestone)

LOE ID:

87883

Pollutant:

Methyl Parathion

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: