Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-SU)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

146037

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 6 of 12 samples exceeded the water quality threshold for Phosphorus as P.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

County of San Diego - Dept of Public Works. 2008. Quality Assurance Project Plan from Southern California Bight. ., Weston Solutions, Inc.. 2014. Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program., Wood. 2019. Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load., Weston Solutions, Inc.. 2019. Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring.

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

145844

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Phosphorus as P.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-CREEK)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

138990

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and the results are as follows: 1 of the 3 samples exceeded the evaluation guideline for Pyrethroids .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The evaluation guideline for the protection of aquatic life from pyrethroids is one toxic unit equivalent. A toxic unit equivalent is equal to the sum of; Bifenthrin, Cyfluthrin, Cypermethrin, Lambda-Cyhalothrin, and Permethrin, each having their reported concentration divided their respective evaluation guideline prior to being summed. If this results in a value greater than one, the sample day is considered to be in exceedance of the water quality standard. (Department of Fish and Game Aquatic Life Criteria for Pyrethroid Insecticides, 2000)

Guideline Reference:

Guideline Reference:

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

Guideline Reference:

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

Guideline Reference:

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

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

146229

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and the results are as follows: 4 of the 4 samples exceeded the water quality threshold for Pyrethroids. Although a total of 5 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, San Diego Basin).

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144138

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 9 of 12 samples exceeded the water quality threshold for Nitrogen, Total.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144098

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 4 of 4 samples exceeded the water quality threshold for Nitrogen, Total.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-CREEK)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144065

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 3 of 4 samples exceeded the water quality threshold for Nitrogen, Total.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-SU)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144153

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 10 of 11 samples exceeded the water quality threshold for Nitrogen, Total.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-COMP)

Temporal Representation:

The samples were collected between the dates of 2016-07-13 and 2017-08-23

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

143962

Pollutant:

Total Nitrogen as N

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-COMP)

Temporal Representation:

The samples were collected between the dates of 2016-07-13 and 2017-08-23

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

143999

Pollutant:

Total Nitrogen as N

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-TRIBUTARY)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144285

Pollutant:

Total Nitrogen as N

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-TRIBUTARY)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144099

Pollutant:

Total Nitrogen as N

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-CREEK)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144284

Pollutant:

Total Nitrogen as N

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-SU)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

134626

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:

1 of the 4 samples collected by San Diego Region NPDES for Loma Alta 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, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Selenastrum capricornutum, for Growth (Chlorophyll a)

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board.

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 station. Monitoring site: ( LAC-TWAS-1 )

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2011-05-10.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

26774

Pollutant:

Sediment Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Ambient toxicity testing (chronic)

Data Used to Assess Water Quality:

Four samples were collected at Loma Alta Creek station 3, 904CBLAC3 from March 2002 to September 2002. The tests showed significant toxicity levels (SL) in the following tests: Hyalella azteca - Two of the four samples exhibited toxicity. Toxicity testing was part of California's Surface Water Ambient Monitoring Program Report, 2007.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

According to SWAMP, waters are considered toxic when samples show significant toxicity levels (SWAMP code ¿SL¿) when compared to a negative control. Significant toxicity is determined when statistical tests result in an alpha of less than 5% and percent control values less than the evaluation threshold.

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Water Toxicity Samples were collected at Loma Alta Creek station 3 (904CBLAC3). (Latitude 33.2000, Longitude -117.3306).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

8875

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Four water samples were collected at Loma Alta Creek station 904CBLAC3 on March, April, June and September 2002. All samples showed excessive selenium concentrations according to results in California's Surface Water Ambient Monitoring Program Report, 2007.

Data Reference:

Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California; Rule. 40 CFR Part 131. U.S. Environmental Protection Agency, Region IX, Water Division, San Francisco, CA

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

CTR Freshwater Chronic (CCC) 5 ug/L; (U.S. EPA, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Water samples were collected at Loma Alta Creek station 3 904CBLAC3; (Latitude 33.2000659, Longitude -117.330675).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

21384

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Ambient toxicity testing (chronic)

Data Used to Assess Water Quality:

Four samples were collected at Loma Alta Creek station 3, 904CBLAC3 from March 2002 to September 2002. The tests showed significant toxicity levels (SL) in the following tests: Selenastrum algae growth test - All four samples exhibited toxicity. Ceriodaphnia dubia survival/reproductive test - three of the four samples exhibited toxicity. Toxicity testing was part of California's Surface Water Ambient Monitoring Program Report, 2007.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Water Toxicity Samples were collected at Loma Alta Creek station 3 (904CBLAC3). (Latitude 33.2000, Longitude -117.3306).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

74143

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:

Four samples were collected to test for toxicity. Four of the four samples exhibited statistically significant toxicity. The toxicity tests that exhibited significant toxicity included survival of Hyalella azteca, reproduction of Ceriodaphnia dubia, and growth of Selenastrum capriconutum.

Data Reference:

Data for Various Pollutants from the County of San Diego Copermittees Receiving Waters Monitoring and Reporting Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012

Evaluation Guideline:

Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. The t-test is used to determine if there is a statistically significant decrease in organism response in the sample as compared to the control.

Guideline Reference:

Guideline Reference:

Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013

Spatial Representation:

The samples were collected at station 904LAC-TWAS-1 Loma Alta Creek.

Temporal Representation:

The samples were collected from 2007 to 2008.

Environmental Conditions:

QAPP Information:

The data was collected under the County of San Diego Co-Permittees Receiving Waters Urban Runoff Monitoring and Reporting Program (Order No. 2007-01). Data quality is good.

QAPP Information Reference(s):

e-mail clarifying QAPP information

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

79488

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Eight of the eight samples collected were below the 0.79 threshold, and are therefore exceeding the water quality objective for the aquatic life beneficial use.

Data Reference:

Data for Various Pollutants from the County of San Diego Copermittees Receiving Waters Monitoring and Reporting Program, 2001-2008.

Region 9 CSCI Scores & Water Body Information

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant or animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board. Region 9 Basin Plan.

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at stations 904LAC-TWAS-1, LAC-CB, and LAC-ECR on Loma Alta Creek.

Temporal Representation:

The samples were collected in May and October 2001 to 2002 and in May 2008 and 2008.

Environmental Conditions:

QAPP Information:

County of San Diego NPDES MS4 Copermittees Receiving Waters Monitoring and Reporting Program

QAPP Information Reference(s):

Quality Assurance Project Plan for SWAMP Bioassessment and Freshwater Bioassessment.

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

215710

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm 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 904M21764 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the threshold. CSCI scores were from 0.56131802 to 0.56131802 .

Data Reference:

California Stream Condition Index Scores for the 2020 Integrated Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from station 904M21764

Temporal Representation:

Samples were collected from 4/17/2018 to 4/17/2018.

Environmental Conditions:

QAPP Information:

The data was collected under a permit required receiving waters monitoring and reporting program

QAPP Information Reference(s):

Quality Assurance Project Plan for Southern California Regional Watershed Monitoring Program Bioassessment, Version 1.0, and Freshwater Bioassessment from Weston Solutions.

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

215700

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm 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 904LTWAS1 to determine beneficial use support and the results are as follows: 4 of 4 samples exceeded the threshold. CSCI scores were from 0.4763 to 0.6438 .

Data Reference:

California Stream Condition Index Scores for the 2020 Integrated Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from station 904LTWAS1

Temporal Representation:

Samples were collected from 2011 to 2015.

Environmental Conditions:

QAPP Information:

The data was collected under a permit required receiving waters monitoring and reporting program

QAPP Information Reference(s):

Quality Assurance Project Plan for Southern California Regional Watershed Monitoring Program Bioassessment, Version 1.0, and Freshwater Bioassessment from Weston Solutions.

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

228003

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 2 of 2 samples exceeded the water quality threshold for Pyrethroids.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Weston, The Regional Monitoring Workgroup Urban Runoff Monitoring Final Report Methods Sections and Statements of Work, and Weston Solutions Inc. Desk Reference for Quality Control Of Work Products.

Evaluation Guideline:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2007-11-30 and 2008-02-03

Environmental Conditions:

QAPP Information:

The Quality Assurance Project Plan from Weston, The Regional Monitoring Workgroup Urban Runoff Monitoring Final Report Methods Sections and Statements of Work, and Weston Solutions Inc. Desk Reference for Quality Control Of Work Products.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

227884

Pollutant:

Bifenthrin

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:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

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

Guideline Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2007-11-30 and 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

135987

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Guideline Reference:

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

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

140489

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 4 of 4 samples exceeded the water quality threshold for Bifenthrin.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

144790

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 2 of 2 samples exceeded the water quality threshold for Permethrin.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

The chronic concentration goal for Permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Permethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2012-10-11 and 2014-11-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

145662

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Phosphorus as P.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-COMP)

Temporal Representation:

The samples were collected between the dates of 2016-07-13 and 2017-08-23

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126444, Benthic Community Effects	Region 9
Loma Alta Creek

LOE ID:

145766

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Long-Term WQ Monitoring at Loma Alta Slough data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality threshold for Phosphorus as P.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-TRIBUTARY)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-07-06

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):


DECISION ID	111533	Region 9
Loma Alta Creek

Pollutant:	Bifenthrin
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
Expected TMDL Completion Date:	2027
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under sections 4.1 and 4.6 of the Listing Policy. Under sections 4.1 and 4.6, at least one line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Six of six samples exceed the water quality threshold in water. One of three samples exceed the chemistry threshold in sediment, but this sample size is insufficient to determine beneficial use support with the statistical power and confidence of the Listing Policy. 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. Six of six samples exceed the water quality threshold in water, and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

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 111533, Bifenthrin	Region 9
Loma Alta Creek

LOE ID:

140489

Pollutant:

Bifenthrin

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111533, Bifenthrin	Region 9
Loma Alta Creek

LOE ID:

227884

Pollutant:

Bifenthrin

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:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2007-11-30 and 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111533, Bifenthrin	Region 9
Loma Alta Creek

LOE ID:

135987

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

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

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111533, Bifenthrin	Region 9
Loma Alta Creek

LOE ID:

140677

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

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

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2013-02-09 to 2013-02-09

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111527	Region 9
Loma Alta Creek

Pollutant:	Selenium
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2019
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 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess pollutant. Four of the 20 samples exceed the water quality threshold. 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. Four of 20 samples exceeded the threshold, and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

8875

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

CTR Freshwater Chronic (CCC) 5 ug/L; (U.S. EPA, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Water samples were collected at Loma Alta Creek station 3 904CBLAC3; (Latitude 33.2000659, Longitude -117.330675).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

74143

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:

Data for Various Pollutants from the County of San Diego Copermittees Receiving Waters Monitoring and Reporting Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Spatial Representation:

The samples were collected at station 904LAC-TWAS-1 Loma Alta Creek.

Temporal Representation:

The samples were collected from 2007 to 2008.

Environmental Conditions:

QAPP Information:

The data was collected under the County of San Diego Co-Permittees Receiving Waters Urban Runoff Monitoring and Reporting Program (Order No. 2007-01). Data quality is good.

QAPP Information Reference(s):

e-mail clarifying QAPP information

Line of Evidence (LOE) for Decision ID 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

21384

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Ambient toxicity testing (chronic)

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Water Toxicity Samples were collected at Loma Alta Creek station 3 (904CBLAC3). (Latitude 33.2000, Longitude -117.3306).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

146079

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for Selenium.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

77791

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Selenium.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

The Quality Assurance Project Plan from Weston, the Regional Monitoring Workgroup Urban Runoff Monitoring Final Report Methods Sections and Statements of Work, and Weston Solutions Inc. Desk Reference for Quality Control Of Work Products were followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111527, Selenium	Region 9
Loma Alta Creek

LOE ID:

146078

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111529	Region 9
Loma Alta Creek

Pollutant:	Toxicity
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under sections 4.1 and 4.6 of the Listing Policy. Under sections 4.1 and 4.6, at least one line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Nine of 12 water samples exhibited toxicity, and two of four sediment samples exhibited toxicity. 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. Nine of 12 water samples and two of four sediment samples exhibited toxicity, and this sample size is sufficient to determine beneficial use support, with the power and confidence of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

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 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

79488

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Eight of the eight samples collected were below the 0.79 threshold, and are therefore exceeding the water quality objective for the aquatic life beneficial use.

Data Reference:

Data for Various Pollutants from the County of San Diego Copermittees Receiving Waters Monitoring and Reporting Program, 2001-2008.

Region 9 CSCI Scores & Water Body Information

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at stations 904LAC-TWAS-1, LAC-CB, and LAC-ECR on Loma Alta Creek.

Temporal Representation:

The samples were collected in May and October 2001 to 2002 and in May 2008 and 2008.

Environmental Conditions:

QAPP Information:

County of San Diego NPDES MS4 Copermittees Receiving Waters Monitoring and Reporting Program

QAPP Information Reference(s):

Quality Assurance Project Plan for SWAMP Bioassessment and Freshwater Bioassessment.

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

21384

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Ambient toxicity testing (chronic)

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Water Toxicity Samples were collected at Loma Alta Creek station 3 (904CBLAC3). (Latitude 33.2000, Longitude -117.3306).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

74143

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:

Data for Various Pollutants from the County of San Diego Copermittees Receiving Waters Monitoring and Reporting Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Spatial Representation:

The samples were collected at station 904LAC-TWAS-1 Loma Alta Creek.

Temporal Representation:

The samples were collected from 2007 to 2008.

Environmental Conditions:

QAPP Information:

The data was collected under the County of San Diego Co-Permittees Receiving Waters Urban Runoff Monitoring and Reporting Program (Order No. 2007-01). Data quality is good.

QAPP Information Reference(s):

e-mail clarifying QAPP information

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

8875

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

CTR Freshwater Chronic (CCC) 5 ug/L; (U.S. EPA, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Water samples were collected at Loma Alta Creek station 3 904CBLAC3; (Latitude 33.2000659, Longitude -117.330675).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

26774

Pollutant:

Sediment Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Ambient toxicity testing (chronic)

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Water Toxicity Samples were collected at Loma Alta Creek station 3 (904CBLAC3). (Latitude 33.2000, Longitude -117.3306).

Temporal Representation:

Samples were collected on March, April, June and September 2002.

Environmental Conditions:

QAPP Information:

Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

134626

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 station. Monitoring site: ( LAC-TWAS-1 )

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2011-05-10.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

26722

Pollutant:

Benthic Community Effects

LOE Subgroup:

Adverse Biological Responses

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Seven samples of IBI data were taken from May 2001 to October 2002 at two sampling sites. All seven of the samples exceeded the IBI impairment threshold.

Data Reference:

Stream Bioassessment Data. Co-permitee Data. Collected 2002-2007

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the San Diego Basin Plan the objective is: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board.

Objective/Criterion Reference:

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

Evaluation Guideline:

The Index of Biological Integrity (IBI) is an analytical tool that can be used to assess the biological and physical condition of streams and rivers within a zero to one hundred scoring range: Very Poor 0-19, Poor 20-39, Fair 40-59, Good 60- 79, Very Good 80-100. The IBI score of 39 was set as an impairment threshold because it is a statistical criterion of two standard deviations below the mean reference site score which defines the boundary between 'fair' and 'poor' IBI creek conditions. (Ode, p. 9)

Guideline Reference:

Spatial Representation:

Samples were collected at two sites: LAC-CB and LAC-ECR on Loma Alta Creek.

Temporal Representation:

Sampling occurred during May and October in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Quality Control for collection and identification was conducted in accordance with the Quality Assurance Manual for Freshwater Bioassessment.

QAPP Information Reference(s):

Quality Assurance Manual for Freshwater Bioassessment Revision 0

Line of Evidence (LOE) for Decision ID 111529, Toxicity	Region 9
Loma Alta Creek

LOE ID:

26415

Pollutant:

Benthic Community Effects

LOE Subgroup:

Adverse Biological Responses

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Eleven samples of IBI data were taken from May 1998 to November 2000 at two sampling sites. All 11 samples exceeded the IBI impairment threshold.

Data Reference:

Fish and Game IBI Data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at two sites: 904LACECR and 904LACCBx on Loma Alta Creek.

Temporal Representation:

Sampling occurred during two to three events from May 1998 to November 2000.

Environmental Conditions:

QAPP Information:

Quality Control for collection and identification was conducted in accordance with the Quality Assurance Project Plan for the California Stream Bioassessment Procedure and the State of California, California Monitoring an Assessment Program: "CMAP", Quality Assurance Project Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan for the California Stream Bioassessment Procedure

QAPP Information Reference(s):

State of California, California Monitoring and Assessment Program: "CMAP".

QAPP Information Reference(s):

The San Diego Stream Team Quality Assurance Project Plan


DECISION ID	127870	Region 9
Loma Alta 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:

Line of Evidence (LOE) for Decision ID 127870, Ammonia	Region 9
Loma Alta Creek

LOE ID:

184916

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-10-06 and 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	115505	Region 9
Loma Alta Creek

Pollutant:	Ammonia (Unionized)
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:

Line of Evidence (LOE) for Decision ID 115505, Ammonia (Unionized)	Region 9
Loma Alta Creek

LOE ID:

185452

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and the results are as follows: 0 of the 4 samples exceeded the water quality threshold for Ammonia as N, Unionized. Although a total of 5 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The discharge of wastes shall not cause concentrations of un-ionized ammonia (NH3) to exceed 0.025 mg/l (as N) in inland surface waters, enclosed bays and estuaries and coastal lagoons (Water Quality Control Plan, San Diego Basin).

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-10-06 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111516	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 16 samples exceed the water quality threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111516, Arsenic	Region 9
Loma Alta Creek

LOE ID:

140348

Pollutant:

Arsenic

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111516, Arsenic	Region 9
Loma Alta Creek

LOE ID:

74145

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Arsenic.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111516, Arsenic	Region 9
Loma Alta Creek

LOE ID:

140136

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111517	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 16 samples exceed the water quality threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111517, Cadmium	Region 9
Loma Alta Creek

LOE ID:

74149

Pollutant:

Cadmium

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Cadmium.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Cadmium to protect aquatic life in freshwater. The dissolved Cadmium criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111517, Cadmium	Region 9
Loma Alta Creek

LOE ID:

140767

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	126827	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 126827, Chlorpyrifos	Region 9
Loma Alta Creek

LOE ID:

77789

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Chlorpyrifos.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in the water column, sediments or biota at concentration(s) that adversely affect beneficial uses. Pesticides shall not be present at levels which will bioaccumulate in aquatic organisms to levels which are harmful to human health, wildlife or aquatic organisms (Water Quality Control Plan, San Diego Basin).

Objective/Criterion Reference:

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

Evaluation Guideline:

The freshwater criterion continuous concentration to protect aquatic organisms is 0.014 ug/L (Siepmann and Finlayson 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 126827, Chlorpyrifos	Region 9
Loma Alta Creek

LOE ID:

219692

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for Chlorpyrifos.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (4 day average)(Siepmann and Finlayson 2000).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111542	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 16 samples exceed the water quality threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111542, Chromium	Region 9
Loma Alta Creek

LOE ID:

141423

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111542, Chromium	Region 9
Loma Alta Creek

LOE ID:

74151

Pollutant:

Chromium

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Chromium.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Chromium to protect aquatic life in freshwater. The dissolved Chromium criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111518	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 16 samples exceed the water quality threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111518, Copper	Region 9
Loma Alta Creek

LOE ID:

141491

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111518, Copper	Region 9
Loma Alta Creek

LOE ID:

74152

Pollutant:

Copper

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Copper.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Copper to protect aquatic life in freshwater. The dissolved Copper criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111534	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 111534, Cypermethrin	Region 9
Loma Alta Creek

LOE ID:

227744

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Evaluation Guideline:

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

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2007-11-30 to 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111534, Cypermethrin	Region 9
Loma Alta Creek

LOE ID:

141961

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Cypermethrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2012-10-11 and 2012-10-11

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111534, Cypermethrin	Region 9
Loma Alta Creek

LOE ID:

141993

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111534, Cypermethrin	Region 9
Loma Alta Creek

LOE ID:

136935

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Cypermethrin, Total .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111540	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 111540, Deltamethrin	Region 9
Loma Alta Creek

LOE ID:

142073

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 5 samples exceeded the water quality threshold for Deltamethrin.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Deltamethrin is the USEPA Aquatic Life Benchmark of 0.0041 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111540, Deltamethrin	Region 9
Loma Alta Creek

LOE ID:

136965

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111540, Deltamethrin	Region 9
Loma Alta Creek

LOE ID:

227623

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceed the water quality threshold for Deltamethrin.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Deltamethrin is the USEPA Aquatic Life Benchmark of 0.0041 ug/L for a invertebrate (acute).

Guideline Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 11/30/2007-2/3/2008.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111544	Region 9
Loma Alta Creek

Pollutant:	Demeton
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:

Line of Evidence (LOE) for Decision ID 111544, Demeton	Region 9
Loma Alta Creek

LOE ID:

142317

Pollutant:

Demeton

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 7 samples exceeded the water quality threshold for Demeton, Total.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

The USEPA National Recomm. Water Quality criteria, 4-day avg. is 0.1 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111519	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 111519, Diazinon	Region 9
Loma Alta Creek

LOE ID:

74157

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Diazinon.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111519, Diazinon	Region 9
Loma Alta Creek

LOE ID:

142233

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Diazinon.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

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

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111520	Region 9
Loma Alta Creek

Pollutant:	Dichlorvos
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 111520, Dichlorvos	Region 9
Loma Alta Creek

LOE ID:

142222

Pollutant:

Dichlorvos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 7 samples were collected, 7 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-09-15 to 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111535	Region 9
Loma Alta Creek

Pollutant:	Dimethoate
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 because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111535, Dimethoate	Region 9
Loma Alta Creek

LOE ID:

142367

Pollutant:

Dimethoate

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111545	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 111545, Esfenvalerate/Fenvalerate	Region 9
Loma Alta Creek

LOE ID:

137389

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The evaluation guideline for esfenvalerate/fenvalerate is the median lethal concentration (LC50) of 1.5 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.5 ug/g is the geometric mean of LC50 values for esfenvalerate/fenvalerate from Amweg et al. (2005).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111545, Esfenvalerate/Fenvalerate	Region 9
Loma Alta Creek

LOE ID:

142540

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 5 samples were collected, 5 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Criteria Report for Esfenvalerate

Evaluation Guideline:

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

Guideline Reference:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111545, Esfenvalerate/Fenvalerate	Region 9
Loma Alta Creek

LOE ID:

227908

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Criteria Report for Esfenvalerate

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2007-11-30 to 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111536	Region 9
Loma Alta Creek

Pollutant:	Ethoprop
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:

Line of Evidence (LOE) for Decision ID 111536, Ethoprop	Region 9
Loma Alta Creek

LOE ID:

142630

Pollutant:

Ethoprop

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Ethoprop is the USEPA Aquatic Life Benchmark of 0.8 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111543	Region 9
Loma Alta Creek

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111543, Fenpropathrin	Region 9
Loma Alta Creek

LOE ID:

137503

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the evaluation guideline for Fenpropathrin .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2012-10-16 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111543, Fenpropathrin	Region 9
Loma Alta Creek

LOE ID:

142706

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.06 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111515	Region 9
Loma Alta Creek

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 111515, Fenvalerate	Region 9
Loma Alta Creek

LOE ID:

142798

Pollutant:

Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Fenvalerate.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

OPP Pesticide Ecotoxicity Database.

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2011-02-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111521	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 16 samples exceeded the threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111521, Lead	Region 9
Loma Alta Creek

LOE ID:

74159

Pollutant:

Lead

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Lead.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Lead to protect aquatic life in freshwater. The dissolved Lead criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111521, Lead	Region 9
Loma Alta Creek

LOE ID:

143188

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111538	Region 9
Loma Alta Creek

Pollutant:	Naled
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:

Line of Evidence (LOE) for Decision ID 111538, Naled	Region 9
Loma Alta Creek

LOE ID:

143345

Pollutant:

Naled

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Naled.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Naled is the USEPA Aquatic Life Benchmark of 0.045 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111522	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 16 samples exceeded the threshold and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111522, Nickel	Region 9
Loma Alta Creek

LOE ID:

74161

Pollutant:

Nickel

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Nickel.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Nickel to protect aquatic life in freshwater. The dissolved Nickel criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111522, Nickel	Region 9
Loma Alta Creek

LOE ID:

143523

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111523	Region 9
Loma Alta 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:

Line of Evidence (LOE) for Decision ID 111523, Oxygen, Dissolved	Region 9
Loma Alta Creek

LOE ID:

144591

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 4 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen levels shall not be less than 5.0 mg/l in inland surface waters with the WARM beneficial use designated (Water Quality Control Plan, San Diego Basin).

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2014-09-10 and 2015-05-13

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111524	Region 9
Loma Alta Creek

Pollutant:	Parathion
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:

Line of Evidence (LOE) for Decision ID 111524, Parathion	Region 9
Loma Alta Creek

LOE ID:

144938

Pollutant:

Parathion

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

The USEPA recommended freshwater aquatic life ambient water quality chronic criteria for Parathion is 0.013 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	130374	Region 9
Loma Alta Creek

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 130374, Permethrin	Region 9
Loma Alta Creek

LOE ID:

138650

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The evaluation guideline for permethrin is the median lethal concentration (LC50) of 8.9 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 8.9 ug/g is the geometric mean of LC50 values for permethrin from Amweg et al. (2005).

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 130374, Permethrin	Region 9
Loma Alta Creek

LOE ID:

144988

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Permethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 130374, Permethrin	Region 9
Loma Alta Creek

LOE ID:

227839

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Permethrin

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2007-11-30 to 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111537	Region 9
Loma Alta Creek

Pollutant:	Phorate
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:

Line of Evidence (LOE) for Decision ID 111537, Phorate	Region 9
Loma Alta Creek

LOE ID:

145677

Pollutant:

Phorate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2013-05-02

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111528	Region 9
Loma Alta 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:	Do Not List on 303(d) list (TMDL required list)(2018)
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 111528, Total Dissolved Solids	Region 9
Loma Alta Creek

LOE ID:

3167

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Two samples were collected by the Regional Board on 5/20/1998 at two locations on Loma Alta Creek. Both samples exceeded the water quality objective.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for total dissolved solids is 500 mg/L. This concentration is not to be exceeded more than 10% of the time during any one year period.

Objective/Criterion Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Two samples were taken along Loma Alta Creek; one at College Blvd. and one at El Camino Real.

Temporal Representation:

One sample was taken at each of the two locations on one day, 5/20/1998.

Environmental Conditions:

QAPP Information:

Data was used in the 2002 assessment.

QAPP Information Reference(s):


DECISION ID	111530	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	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 111530, Turbidity	Region 9
Loma Alta Creek

LOE ID:

147559

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 2 of 12 samples exceeded the water quality threshold for Turbidity.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Turbidity water quality threshold in this HSA is 20 NTU, and this level is not to be exceeded more than 10% of the time during any one year period (Basin Plan, Table 3-2).

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-13

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111530, Turbidity	Region 9
Loma Alta Creek

LOE ID:

3168

Pollutant:

Turbidity

LOE Subgroup:

Adverse Biological Responses

Matrix:

-N/A

Fraction:

Dissolved

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Samples were collected by RWQCB9 at two locations on Loma Alta Creek on 5/20/1998. No samples were in exceedance. (SWRCB, 2003).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Basin Plan: For inland surface waters with all beneficial uses, the WQO for Turbidity is 20 NTU. This concentration is not to be exceeded more than 10% of the time during any one year period.

Objective/Criterion Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Two samples, one at each location, were collected along Loma Alta Creek at College Blvd. and El Camino Real.

Temporal Representation:

Samples were collected once on 5/20/1998

Environmental Conditions:

QAPP Information:

Dataset was used in 2002's assessment.

QAPP Information Reference(s):


DECISION ID	111531	Region 9
Loma Alta Creek

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the water quality threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 16 samples exceeded the threshold, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 111531, Zinc	Region 9
Loma Alta Creek

LOE ID:

148120

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111531, Zinc	Region 9
Loma Alta Creek

LOE ID:

74144

Pollutant:

Zinc

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:

State Water Board staff assessed County of San Diego NDPES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Zinc.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations for dissolved Zinc to protect aquatic life in freshwater. The dissolved Zinc criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Loma Alta Creek was collected at 1 monitoring site [ Loma Alta Creek - 904LAC-TWAS-1]

Temporal Representation:

Data was collected over the time period 9/19/2007-5/14/2008.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	111525	Region 9
Loma Alta Creek

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111525, pH	Region 9
Loma Alta Creek

LOE ID:

145492

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

In inland surface waters the pH shall not be depressed below 6.5 nor raised above 8.5.

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-14 and 2015-05-13

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111539	Region 9
Loma Alta Creek

Pollutant:	Cyfluthrin
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

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

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111539, Cyfluthrin	Region 9
Loma Alta Creek

LOE ID:

227842

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Cyfluthrin. Although a total of 2 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

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

Guideline Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1).

Temporal Representation:

Data for this waterbody was collected over the date range 2007-11-30 to 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111539, Cyfluthrin	Region 9
Loma Alta Creek

LOE ID:

142011

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for Cyfluthrin.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2012-10-11 and 2014-11-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111539, Cyfluthrin	Region 9
Loma Alta Creek

LOE ID:

142045

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan from Southern California Bight.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111539, Cyfluthrin	Region 9
Loma Alta Creek

LOE ID:

136589

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	111541	Region 9
Loma Alta Creek

Pollutant:	Cyhalothrin, Lambda
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6, at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. Three lines of evidence are available in the administrative record to assess this pollutant. Two of four samples exceed the water quality threshold in water. Zero of three samples exceed the water quality threshold in sediment, but this sample size is insufficient to determine beneficial use support with the statistical power and confidence of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of four samples exceed the water quality threshold in water, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111541, Cyhalothrin, Lambda	Region 9
Loma Alta Creek

LOE ID:

136641

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111541, Cyhalothrin, Lambda	Region 9
Loma Alta Creek

LOE ID:

143058

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality threshold for Lambda-cyhalothrin.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Evaluation Guideline:

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

Guideline Reference:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2011-02-16 and 2014-11-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111541, Cyhalothrin, Lambda	Region 9
Loma Alta Creek

LOE ID:

227883

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Lambda-cyhalothrin. Although a total of 2 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1).

Temporal Representation:

Data for this waterbody was collected over the date range 2007-11-30 to 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111541, Cyhalothrin, Lambda	Region 9
Loma Alta Creek

LOE ID:

143041

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Diego Region NPDES data for Loma Alta Creek to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Date for this waterbody was collected over the date range 2013-02-09 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	127885	Region 9
Loma Alta Creek

Pollutant:	Indicator Bacteria
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Five of the five samples exceed the GM threshold for E. coli. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Five of five samples exceed the E. coli water quality threshold for the protection of REC-1, and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the upstream reach of this waterbody has salinity levels equal to or less than 1 part per thousand 95 percent or more of the time, and the downstream in reach has salinity levels greater than 1 part per thousand more than 5 percent of the time, both E. coli and enterococci bacteria objectives apply. Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using both objectives for samples taken in the corresponding reaches. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For E. coli and enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody. No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:	The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the upstream reach of this waterbody has salinity levels equal to or less than 1 part per thousand 95 percent or more of the time, and the downstream in reach has salinity levels greater than 1 part per thousand more than 5 percent of the time, both E. coli and enterococci bacteria objectives apply. Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using both objectives for samples taken in the corresponding reaches. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For E. coli and enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody. No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220652

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Loma Alta Creek to determine beneficial use support and the results are as follows: 3 of the 6 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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (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): LA-OS

Temporal Representation:

The samples were collected between the days of 2016-05-11 and 2017-02-15 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220654

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): LA-RDO-SPR

Temporal Representation:

The samples were collected between the days of 2016-05-11 and 2017-02-15 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220651

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Loma Alta Creek to determine beneficial use support and the results are as follows: 4 of the 6 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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): LA-DS-GAR

Temporal Representation:

The samples were collected between the days of 2016-05-11 and 2017-02-15 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220640

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Loma Alta Creek to determine beneficial use support and the results are as follows: 5 of the 5 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective applicable to all non-saline waters, is a geometric mean (GM) of E. coli not to exceed 100 cfu/100 mL. The waterbody GM shall not be greater than the applicable GM magnitude in any six-week interval, calculated weekly (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): LA-CON

Temporal Representation:

The samples were collected between the days of 2016-05-03 and 2017-04-04 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220644

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 data for Loma Alta Creek to determine beneficial use support and the results are as follows: 11 of the 11 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a Statistical Threshold Value (STV) of Enterococci of 110 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (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): LA-PCH

Temporal Representation:

The samples were collected between the days of 2016-05-03 and 2017-04-04 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220660

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 data for Loma Alta Creek to determine beneficial use support and the results are as follows: 3 of the 3 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.

Data Reference:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a geometric mean (GM) of Enterococci not to exceed 30 cfu/100 mL. The waterbody GM shall not be greater than the applicable GM magnitude in any six-week interval, calculated weekly (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): LA-PCH

Temporal Representation:

The samples were collected between the days of 2016-05-03 and 2017-04-04 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek

Line of Evidence (LOE) for Decision ID 127885, Indicator Bacteria	Region 9
Loma Alta Creek

LOE ID:

220642

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Loma Alta Creek to determine beneficial use support and the results are as follows: 10 of the 11 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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): LA-CON

Temporal Representation:

The samples were collected between the days of 2016-05-03 and 2017-04-04 .

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.

QAPP Information Reference(s):

Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek


DECISION ID	111526	Region 9
Loma Alta Creek

Pollutant:	Phosphorus
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. Seven of the 31 samples exceed the threshold. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Seven of 31 samples exceed the threshold and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111526, Phosphorus	Region 9
Loma Alta Creek

LOE ID:

145859

Pollutant:

Phosphorus

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-SU)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111526, Phosphorus	Region 9
Loma Alta Creek

LOE ID:

145662

Pollutant:

Phosphorus

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-COMP)

Temporal Representation:

The samples were collected between the dates of 2016-07-13 and 2017-08-23

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111526, Phosphorus	Region 9
Loma Alta Creek

LOE ID:

145844

Pollutant:

Phosphorus

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-CREEK)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-08-08

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111526, Phosphorus	Region 9
Loma Alta Creek

LOE ID:

146037

Pollutant:

Phosphorus

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, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2015-05-14

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111526, Phosphorus	Region 9
Loma Alta Creek

LOE ID:

145766

Pollutant:

Phosphorus

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:

Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (LA-TRIBUTARY)

Temporal Representation:

The samples were collected between the dates of 2016-07-06 and 2017-07-06

Environmental Conditions:

QAPP Information:

Weston Solutions, Inc. 2015. Final Monitoring Plan: Long Term Water Quality Monitoring at Loma Alta Slough; Quality Assurance Project Plan (Appendix A).

QAPP Information Reference(s):


DECISION ID	111532	Region 9
Loma Alta Creek

Pollutant:	Pyrethroids
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6, at least two lines of evidence are necessary to assess listing status for pollutants sediment, and pollutant concentrations in sediment must be associated with sediment toxicity to justify adding that pollutant to the CWA section 303(d) List. Three lines of evidence are available in the administrative record to assess this pollutant. Six of six samples exceed the water quality threshold in water. One of three samples exceed the water quality threshold in sediment, but this sample size is insufficient to determine beneficial use support with the statistical power and confidence of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Six of six samples exceed the water quality threshold in water, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 111532, Pyrethroids	Region 9
Loma Alta Creek

LOE ID:

228003

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

Evaluation Guideline:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (904LAC-TWAS-1)

Temporal Representation:

The samples were collected between the dates of 2007-11-30 and 2008-02-03

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 111532, Pyrethroids	Region 9
Loma Alta Creek

LOE ID:

146229

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Assurance Project Plan from Southern California Bight.

Evaluation Guideline:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (LAC-TWAS-1).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-02-16 to 2015-03-01

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load

Line of Evidence (LOE) for Decision ID 111532, Pyrethroids	Region 9
Loma Alta Creek

LOE ID:

138990

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 9.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

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

Guideline Reference:

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

Guideline Reference:

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

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): LAC-TWAS-1.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-10-11 to 2014-11-07

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan from Southern California Bight.

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency for NPDES Receiving Water Monitoring

QAPP Information Reference(s):

Quality Assurance Project Plan for the County of San Diego's Inland Surface Water Monitoring Program

QAPP Information Reference(s):

Quality Assurance Project Plan Equivalency Los Penasquitos Watershed Management Area Sediment Load Total Maximum Daily Load


DECISION ID	82871	Region 9
Loma Alta Creek

Pollutant:	Malathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line(s) of evidence are necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the Four samples exceed the Water Quality Criteria for Malathion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of Four samples exceeded the Water Quality Criteria for Malathion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 82871, Malathion	Region 9
Loma Alta Creek

LOE ID:

74160

Pollutant:

Malathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed County of San Diego data for Loma Alta Creek to determine beneficial use support and results are as follows: 1 of 4 samples exceed the criterion for Malathion.

Data Reference:

Data for Various Pollutants from the County of San Diego Department of Public Works Watershed Protection Program, 2001-2008.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference: