Draft California 2026 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 8 - Santa Ana Region

Water Body Name:	San Antonio Creek
Water Body ID:	CAR8012100019991013144655
Water Body Type:	River & Stream


DECISION ID	150263	Region 8
San Antonio Creek

Pollutant:	pH
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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. 11 lines of evidence are available in the administrative record to assess this pollutant. 31 of the 37 samples exceed the COLD pH 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. 31 of the 37 samples exceed the COLD pH 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:	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 150263, pH	Region 8
San Antonio Creek

LOE ID:

298398

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB8 So. CA Stormwater Monitoring Coalition data for San Antonio Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298395

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Middle Santa Ana River TMDL Monitoring Project data for San Antonio Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the dates of 2019-08-06 and 2019-09-03

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

8016

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Of the 29 samples collected 28 exceeded the Basin Plan's objective.

Data Reference:

2006 HCMP Database

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Santa Ana Region's Basin Plan Objective: 6.5 - 8.5 pH units

Objective/Criterion Reference:

Water Quality Control Plan for the Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were taken at one station in San Antonio Creek.

Temporal Representation:

The samples were collected multiple times per month for a period of several years beginning with 1/3/2006 through 2/21/2007.

Environmental Conditions:

QAPP Information:

The data's quality is deemed appropriate because it originated from an NPDES discharger in compliance with their monitoring and reporting program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298401

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB8 So. CA Stormwater Monitoring Coalition data for San Antonio Creek 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, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801S02464 (San Antonio Creek Channel Random SMC Site 02464).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298397

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298399

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB4 So. CA Stormwater Monitoring Coalition data for San Antonio Creek 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, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298338

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801S02464 (San Antonio Creek Channel Random SMC Site 02464).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298396

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:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the dates of 2019-08-06 and 2019-09-03

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298402

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298400

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150263, pH	Region 8
San Antonio Creek

LOE ID:

298339

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:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	146657	Region 8
San Antonio Creek

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 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298357

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298354

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298355

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298356

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298358

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146657, Alkalinity as CaCO3	Region 8
San Antonio Creek

LOE ID:

298353

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

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: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	150604	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 150604, Ammonia	Region 8
San Antonio Creek

LOE ID:

298362

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of contaminants in waters which are existing or potential sources of drinking water shall not occur at levels that are harmful to human health (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The USEPA Health Advisory for lifetime exposure to ammonia as a drinking water level is a concentration of 30 mg/L. This Advisory Level is defined as 'the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.

Guideline Reference:

2018 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150604, Ammonia	Region 8
San Antonio Creek

LOE ID:

316353

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The chronic unionized ammonia objectives (expressed as a 4-day average in mg/L) to protect aquatic life in freshwater are pH and temperature dependent and were calculated according to the formulas specified in Table 4-4 of the Water Quality Control Plan for the Santa Ana River Basin.

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150604, Ammonia	Region 8
San Antonio Creek

LOE ID:

298361

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

2018 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	146643	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146643, Arsenic	Region 8
San Antonio Creek

LOE ID:

298365

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for arsenic is 10 ug/L (California Code of Regulations, Title 22).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146643, Arsenic	Region 8
San Antonio Creek

LOE ID:

298366

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 150 ug/L. The conversion factor used to convert the total fraction criterion for arsenic to dissolved fraction criterion is 1. Therefore all data was considered to be representative of the dissolved fraction. (California Toxics Rule, 2000)

Objective/Criterion Reference:

Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146643, Arsenic	Region 8
San Antonio Creek

LOE ID:

298367

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	154027	Region 8
San Antonio Creek

Pollutant:	Benthic Community Effects
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:	Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects. One line(s) of evidence evaluating benthic-macroinvertebrate bioassessment data is/are available in the administrative record to assess this indicator. One of one benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this waterbody segment on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of one benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 154027, Benthic Community Effects	Region 8
San Antonio Creek

LOE ID:

314257

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for 801S02464 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the threshold. CSCI scores were from 0.694899573 to 0.694899573.

Data Reference:

California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Inland surface water communities and populations, including vertebrate, invertebrate, and plant species, shall not be degraded as a result of the discharge of waste. Degradation is damage to an aquatic community or population with the result that balanced community no longer exists. The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

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

Guideline Reference:

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

Spatial Representation:

Samples were collected from station 801S02464.

Temporal Representation:

Samples were collected from 6/22/2011 to 6/22/2011.

Environmental Conditions:

QAPP Information:

Data collected following SWAMP QA protocols.

QAPP Information Reference(s):

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


DECISION ID	146644	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146644, Cadmium	Region 8
San Antonio Creek

LOE ID:

298369

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146644, Cadmium	Region 8
San Antonio Creek

LOE ID:

298370

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146644, Cadmium	Region 8
San Antonio Creek

LOE ID:

298368

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for cadmium is 0.005 mg/L (California Code of Regulations, Title 22).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146645	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298418

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298404

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298415

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298403

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298414

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298416

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298419

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298417

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146645, Chloride	Region 8
San Antonio Creek

LOE ID:

298405

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Chloride shall not exceed 6 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	146658	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146658, Chromium	Region 8
San Antonio Creek

LOE ID:

298371

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146658, Chromium	Region 8
San Antonio Creek

LOE ID:

298372

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for total chromium is 0.05 mg/L (California Code of Regulations, Title 22).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146658, Chromium	Region 8
San Antonio Creek

LOE ID:

298373

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146646	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146646, Copper	Region 8
San Antonio Creek

LOE ID:

298375

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The copper criterion for the protection of human health from the consumption of water and organisms is 1,300 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146646, Copper	Region 8
San Antonio Creek

LOE ID:

298376

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146646, Copper	Region 8
San Antonio Creek

LOE ID:

298374

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146656	Region 8
San Antonio Creek

Pollutant:	Hardness 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 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298408

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB8 So. CA Stormwater Monitoring Coalition data for San Antonio Creek to determine beneficial use support and results are as follows: 2 of 2 samples exceeded the water quality standard for Hardness as CaCO3.

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298406

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298420

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB8 So. CA Stormwater Monitoring Coalition data for San Antonio Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality standard for Hardness as CaCO3.

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298407

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298421

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146656, Hardness as CaCO3	Region 8
San Antonio Creek

LOE ID:

298422

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Hardness shall not exceed 70 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	149170	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 149170, Indicator Bacteria	Region 8
San Antonio Creek

LOE ID:

300930

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

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 Middle Santa Ana River TMDL Monitoring Project data for San Antonio Creek to determine beneficial use support and the results are as follows: 2 of the 2 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use for waters where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (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): T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the days of 2019-07-30 and 2019-09-03 .

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program

Line of Evidence (LOE) for Decision ID 149170, Indicator Bacteria	Region 8
San Antonio Creek

LOE ID:

300952

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 Middle Santa Ana River TMDL Monitoring Project data for San Antonio Creek to determine beneficial use support and the results are as follows: 1 of the 3 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:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

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): T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the days of 2019-07-30 and 2019-09-03 .

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program


DECISION ID	146647	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146647, Lead	Region 8
San Antonio Creek

LOE ID:

298377

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146647, Lead	Region 8
San Antonio Creek

LOE ID:

298383

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146647, Lead	Region 8
San Antonio Creek

LOE ID:

298382

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for lead is 15 ug/L (California Code of Regulations, Title 22).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146648	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146648, Nickel	Region 8
San Antonio Creek

LOE ID:

298378

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146648, Nickel	Region 8
San Antonio Creek

LOE ID:

298380

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146648, Nickel	Region 8
San Antonio Creek

LOE ID:

298379

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The maximum contaminant level of nickel in public water systems shall be 0.1 mg/L (California Code of Regulations, Title 22, Division 4, Chapter 15, Sections 64431).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	150904	Region 8
San Antonio Creek

Pollutant:	Nitrogen
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 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303368

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303339

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303338

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303340

Pollutant:

Total Nitrogen as N

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303367

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303369

Pollutant:

Total Nitrogen as N

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:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303337

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150904, Nitrogen	Region 8
San Antonio Creek

LOE ID:

303366

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 4 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	150697	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 150697, Nitrogen, Nitrate	Region 8
San Antonio Creek

LOE ID:

298381

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Nitrate-nitrogen concentrations shall not exceed 10 mg/L (as N) in inland surface waters designated MUN as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150697, Nitrogen, Nitrate	Region 8
San Antonio Creek

LOE ID:

298384

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	150660	Region 8
San Antonio Creek

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

Regional Board Conclusion:	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 150660, Nitrogen, Nitrite	Region 8
San Antonio Creek

LOE ID:

298385

Pollutant:

Nitrogen, Nitrite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for nitrite (as N) is 1.0 mg/L (Title 22 of the California Code of Regulations).

Guideline Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150660, Nitrogen, Nitrite	Region 8
San Antonio Creek

LOE ID:

298386

Pollutant:

Nitrogen, Nitrite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for nitrite (as N) is 1.0 mg/L (Title 22 of the California Code of Regulations).

Guideline Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146649	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298388

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, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298392

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298394

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:

Water Board staff assessed Middle Santa Ana River TMDL Monitoring Project data for San Antonio Creek to determine beneficial use support and results are as follows: 1 of 6 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the dates of 2019-07-30 and 2019-09-03

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298387

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved oxygen content of surface waters shall not be depressed below 6 mg/L for waters designated COLD as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801S02464 (San Antonio Creek Channel Random SMC Site 02464).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298389

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298390

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, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801S02464 (San Antonio Creek Channel Random SMC Site 02464).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298393

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146649, Oxygen, Dissolved	Region 8
San Antonio Creek

LOE ID:

298391

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the dates of 2019-07-30 and 2019-09-03

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program


DECISION ID	146650	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146650, Selenium	Region 8
San Antonio Creek

LOE ID:

298337

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146650, Selenium	Region 8
San Antonio Creek

LOE ID:

298335

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Maximum Contaminant Level for selenium is 0.05 mg/L (California Code of Regulations, Title 22).

Guideline Reference:

California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146650, Selenium	Region 8
San Antonio Creek

LOE ID:

298336

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146651	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298425

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298423

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298426

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298410

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298424

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, 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:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481S05856)

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146651, Sulfates	Region 8
San Antonio Creek

LOE ID:

298409

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Sulfate shall not exceed 25 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	146652	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146652, Temperature, water	Region 8
San Antonio Creek

LOE ID:

298343

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:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481M15356 (San Antonio Creek Random SMC Site 15356).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146652, Temperature, water	Region 8
San Antonio Creek

LOE ID:

298340

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801S02464 (San Antonio Creek Channel Random SMC Site 02464).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146652, Temperature, water	Region 8
San Antonio Creek

LOE ID:

298344

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146652, Temperature, water	Region 8
San Antonio Creek

LOE ID:

298341

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 801SNP002 (San Antonio Creek Non-perennial site 002).

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146652, Temperature, water	Region 8
San Antonio Creek

LOE ID:

298342

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 Middle Santa Ana River TMDL Monitoring Project data for San Antonio Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: T1-SACH (San Antonio Creek Channel @ SR 60).

Temporal Representation:

The samples were collected between the dates of 2019-08-06 and 2019-09-03

Environmental Conditions:

QAPP Information:

CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.

QAPP Information Reference(s):

Santa Ana River Watershed Bacteria Monitoring Program


DECISION ID	146653	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298429

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298428

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298427

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (481M15356)

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298411

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298413

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146653, Total Dissolved Solids	Region 8
San Antonio Creek

LOE ID:

298412

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 225 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (801SNP002)

Temporal Representation:

The samples were collected between the dates of 2014-05-13 and 2014-06-18

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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


DECISION ID	146654	Region 8
San Antonio Creek

Pollutant:	Toxicity
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 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298351

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

1 of the 1 samples collected by RWB8 So. CA Stormwater Monitoring Coalition for San Antonio Creek exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia for Young/female, Ceriodaphnia dubia for Survival. The following tests exhibited toxicity: Ceriodaphnia dubia for Young/female on 2011-06-22.

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The sample is toxic when the response of the organisms exposed to the sample is significantly different (worse) than the response of the organisms exposed to the laboratory control based on statistical hypothesis testing.Â An exceedance is counted when the significant effect code is â€œSignificant; Less Similarity,â€ which means that the sample result is significantly different than the control result, and the percent effect is greater than the evaluation threshold.Â The default evaluation threshold is 20% unless otherwise stated.

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 monitoring site: 801S02464 ( San Antonio Creek Channel Random SMC Site 02464 ).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298348

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:

0 of the 1 samples collected by RWB4 So. CA Stormwater Monitoring Coalition for San Antonio Creek exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca for Growth (wt/surv indiv), Hyalella azteca for Survival.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 481M15356 ( San Antonio Creek Random SMC Site 15356 ).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298347

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 481M15356 ( San Antonio Creek Random SMC Site 15356 ).

Temporal Representation:

The samples were collected between the dates of 2015-06-24 and 2015-06-24.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298350

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:

0 of the 1 samples collected by RWB8 So. CA Stormwater Monitoring Coalition for San Antonio Creek exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia for Survival, Ceriodaphnia dubia for Young/female.

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 481S05856 ( San Antonio Creek Random SMC Site 05856 ).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298352

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:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 801S02464 ( San Antonio Creek Channel Random SMC Site 02464 ).

Temporal Representation:

The samples were collected between the dates of 2011-06-22 and 2011-06-22.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146654, Toxicity	Region 8
San Antonio Creek

LOE ID:

298349

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 481S05856 ( San Antonio Creek Random SMC Site 05856 ).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13.

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	146655	Region 8
San Antonio Creek

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

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 146655, Zinc	Region 8
San Antonio Creek

LOE ID:

298346

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:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

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: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 146655, Zinc	Region 8
San Antonio Creek

LOE ID:

298345

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 481S05856 (San Antonio Creek Random SMC Site 05856).

Temporal Representation:

The samples were collected between the dates of 2013-06-13 and 2013-06-13

Environmental Conditions:

QAPP Information:

SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

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


DECISION ID	74428	Region 8
San Antonio Creek

Pollutant:	Boron
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:	There was no new data considered in the 2014 Listing Cycle, this previously made decision will carryover. The following description applies to an earlier Listing Cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One (1) line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of twenty-eight (28) samples exceeded the Basin Plan 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:	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. 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 74428, Boron	Region 8
San Antonio Creek

LOE ID:

8314

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Of the 28 samples collected none exceeded the Basin Plan's objective

Data Reference:

2006 HCMP Database

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan Objective: 0.75 mg/l

Objective/Criterion Reference:

Water Quality Control Plan for the Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at one station in San Antonio Creek.

Temporal Representation:

The samples were collected multiple times during the month througout a period of several years beginning with 1/3/2006 through 2/21/2007

Environmental Conditions:

QAPP Information:

The data's quality is deemed acceptable because it was submitted by an NPDES discharger in accordance with its Monitoring and Reporting Requirements.

QAPP Information Reference(s):