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

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144615, Allethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

277399

Pollutant:

Allethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144615, Allethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

277400

Pollutant:

Allethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144615, Allethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

277396

Pollutant:

Allethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144625	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144625, Bifenthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

280365

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144625, Bifenthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

280577

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144627	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144627, Cyfluthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283314

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144627, Cyfluthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283379

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144627, Cyfluthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283294

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144627, Cyfluthrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283270

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144629	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144629, Cyhalothrin, Lambda	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284425

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144629, Cyhalothrin, Lambda	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284322

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144629, Cyhalothrin, Lambda	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284302

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144629, Cyhalothrin, Lambda	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284364

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144626	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144626, Cypermethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283141

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144626, Cypermethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283501

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144626, Cypermethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283159

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144626, Cypermethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283593

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144628	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144628, Deltamethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283736

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144628, Deltamethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283475

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144628, Deltamethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283473

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144628, Deltamethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283759

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144631	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144631, Esfenvalerate/Fenvalerate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283494

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144631, Esfenvalerate/Fenvalerate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283500

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144631, Esfenvalerate/Fenvalerate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283478

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144631, Esfenvalerate/Fenvalerate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283493

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144630	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:	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 144630, Fenpropathrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283689

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144630, Fenpropathrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283691

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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144630, Fenpropathrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283713

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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144630, Fenpropathrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283670

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2018-11-23 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144616	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144616, Fipronil Desulfinyl	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284045

Pollutant:

Fipronil Desulfinyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil desulfinyl is the USEPA Aquatic Life Benchmark of 0.54 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144616, Fipronil Desulfinyl	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284065

Pollutant:

Fipronil Desulfinyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil desulfinyl is the USEPA Aquatic Life Benchmark of 0.54 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144616, Fipronil Desulfinyl	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283838

Pollutant:

Fipronil Desulfinyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil desulfinyl is the USEPA Aquatic Life Benchmark of 0.54 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144616, Fipronil Desulfinyl	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284063

Pollutant:

Fipronil Desulfinyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil desulfinyl is the USEPA Aquatic Life Benchmark of 0.54 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144632	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144632, Fipronil Sulfide	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283984

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfide is the USEPA Aquatic Life Benchmark of 0.83 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144632, Fipronil Sulfide	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283962

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfide is the USEPA Aquatic Life Benchmark of 0.83 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144632, Fipronil Sulfide	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283963

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfide is the USEPA Aquatic Life Benchmark of 0.83 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144632, Fipronil Sulfide	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283919

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfide is the USEPA Aquatic Life Benchmark of 0.83 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144633	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144633, Fipronil Sulfone	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283844

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfone is the USEPA Aquatic Life Benchmark of 0.037 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144633, Fipronil Sulfone	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283824

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfone is the USEPA Aquatic Life Benchmark of 0.037 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144633, Fipronil Sulfone	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283779

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfone is the USEPA Aquatic Life Benchmark of 0.037 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144633, Fipronil Sulfone	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284088

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for fipronil degradate fipronil sulfone is the USEPA Aquatic Life Benchmark of 0.037 ug/L for an invertebrate (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144634	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:	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 144634, Permethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286609

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144634, Permethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286520

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144634, Permethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286634

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144634, Permethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286611

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144617	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144617, T-Fluvalinate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288312

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tau-fluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144617, T-Fluvalinate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288292

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tau-fluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144617, T-Fluvalinate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288311

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tau-fluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144617, T-Fluvalinate	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288308

Pollutant:

T-Fluvalinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tau-fluvalinate is the USEPA Aquatic Life Benchmark of 0.064 ug/L for a fish (chronic).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144621	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for conventional or other pollutants (Table 3.2 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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.

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 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298743

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

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:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. The temperature of any cold or warm freshwater habitat shall not be increased by more than 5 degrees F (2.8 degrees C) above natural receiving water temperature.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Scientific literature reviewed by the Washington Department of Ecology and U.S. EPA indicates that stream temperatures higher than 21C are associated with avoidance behavior and migration blockages in steelhead trout.

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Guideline Reference:

U.S. Environmental Protection Agency (USEPA). 2001. Issue Paper 1: Salmonid Behavior and Water Temperature Prepared as Part of EPA Region 10 Temperature Water Quality Criteria Guidance Development Project. Region 10, Seattle, WA. EPA-910-D-01-001 May 2001.

Guideline Reference:

Washington State Department of Ecology (WDOE). 2002. Evaluating Standards for Protecting Aquatic Life in Washington’s Surface Water Quality Standards: Temperature Criteria. Draft Discussion Paper and Literature Summary. Publication Number 00-10-070.

Guideline Reference:

Beschta RL, Bilby RE, Brown GW, Holtby LB, Hofstra TD. 1987. Stream temperature and aquatic habitat: Fisheries and forestry interactions. In: Salo EO, Cundy TW, eds. Streamside management: forestry and fishery interactions. College of Forest Resources, University of Washington, Seattle. Contribution No. 57. Proceedings of a Symposium held at University of Washington, February 12-14, 1986, pp. 191-231.

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the dates of 2017-06-21 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298904

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-02-14 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298750

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2017-02-14 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298973

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298814

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the dates of 2017-06-21 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289002

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: “- The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. - The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature.”

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Per Effects of Temperature, Dissolved Oxygen/Total Dissolved Gas, Ammonia, and pH on Salmonids (Carter 2008, Moyle 1976, and USEPA 1977), the lethal temperature evaluation guideline for both the steelhead adult migration and holding and the steelhead juvenile growth and rearing life stages is 24°C.

Guideline Reference:

Temperature criteria for freshwater fish: protocol and procedures. Ecological Research Series. EPA-600/3-77-061 (NTIS PB270032). Prepared by W.A. Brungs and B.R. Jones. U.S. Environmental Protection Agency, Washington, D.C

Guideline Reference:

Effects of Temperature, Dissolved Oxygen/Total Dissolved Gas, Ammonia, and pH on Salmonids. Implications for California's North Coast TMDLs. California Regional Water Quality Control Board, North Coast Region

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289122

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: “- The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. - The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature.”

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289160

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: “- The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. - The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature.”

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289006

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: “- The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. - The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature.”

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144621, Temperature, water	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289054

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Temperature objectives for surface waters are specified in the San Francisco Bay Regional Water Quality Control Plan. The following temperature objectives apply to surface waters: “- The natural receiving water temperature of inland surface waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. - The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature.”

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144618	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144618, Tetramethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289164

Pollutant:

Tetramethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tetramethrin is the USEPA Aquatic Life Benchmark of 1.85 ug/L for a fish (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144618, Tetramethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289162

Pollutant:

Tetramethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tetramethrin is the USEPA Aquatic Life Benchmark of 1.85 ug/L for a fish (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144618, Tetramethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289180

Pollutant:

Tetramethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tetramethrin is the USEPA Aquatic Life Benchmark of 1.85 ug/L for a fish (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144618, Tetramethrin	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289163

Pollutant:

Tetramethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

The evaluation guideline for tetramethrin is the USEPA Aquatic Life Benchmark of 1.85 ug/L for a fish (acute).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144622	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of 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 144622, Turbidity	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302881

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009). The application of this evaluation guideline was restricted to the dry season (May to October) because runoff and resuspension of fine substrate during storm events may naturally elevate turbidity compared to baseflow conditions. The magnitude and duration of these increases will vary depending on the watershed’s geology and land use and may not represent a chronic turbidity problem. Turbidity is naturally higher in tidal river systems, so sample locations with salinity regimes (i.e., Freshwater or Marine) designated as “Marine” were excluded from this analysis.

Guideline Reference:

The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2019-06-24 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144622, Turbidity	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289558

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Sigler et al. (1984) states that turbidities of 25 NTUs or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food. The application of this evaluation guideline was restricted to the dry season (May to October) because Coho and steelhead early life stages are present during the dry season and feeding becomes infrequent during the winter months (Moyle 2002). Additionally, runoff and resuspension of fine substrate during storm events may naturally elevate turbidity compared to baseflow conditions. The magnitude and duration of these increases will vary depending on the watershed’s geology and land use and may not represent a chronic turbidity problem. Turbidity is naturally higher in tidal river systems, so sample locations with salinity regimes (i.e., Freshwater or Marine) designated as “Marine” were excluded from this analysis.

Guideline Reference:

Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2019-06-24 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144622, Turbidity	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289639

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2019-06-24 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144622, Turbidity	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302852

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2019-06-24 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144620	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma 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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence are available in the administrative record to assess this pollutant. Zero of fifty-three samples exceed the Basin Plan objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of fifty-three samples exceed the Basin Plan objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that though this water body is impaired for sediment toxicity, this water body-pollutant combination should not be placed on the section 303(d) list because applicable the water or sediment quality standards for these pollutants are not being exceeded or are insufficient to determine use support.

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 144620, pH	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287755

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives, Section 3.3.9 pH states: The pH shall not be depressed below 6.5 nor raised above 8.5. This encompasses the pH range usually found in waters within the basin. Controllable water quality factors shall not cause changes greater than 0.5 units in normal ambient pH levels.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-02-14 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144620, pH	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287506

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2017-02-14 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144620, pH	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287436

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the dates of 2017-06-21 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144620, pH	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287717

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the dates of 2017-06-21 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144620, pH	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287699

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144619	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Forty-three of the eighty-six samples exceed the Basin Plan COLD dissolved oxygen objective. 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. Forty-three of the eighty-six samples exceed the Basin Plan COLD dissolved oxygen objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286314

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as warm water habitat shall be of a 5.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286195

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as warm water habitat shall be of a 5.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285949

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as cold water habitat shall be of a 7.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286475

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as cold water habitat shall be of a 7.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286242

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as warm water habitat shall be of a 5.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286312

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as warm water habitat shall be of a 5.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286243

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as warm water habitat shall be of a 5.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285879

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as cold water habitat shall be of a 7.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286497

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as cold water habitat shall be of a 7.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-02-07 and 2019-07-15

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144619, Oxygen, Dissolved	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286498

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Dissolved oxygen objectives for waters designated as cold water habitat shall be of a 7.0 mg/l minimum. (Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives.)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2018-06-05

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144624	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

Pollutant:	Fipronil
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Other Urban Runoff \| Surface Runoff
TMDL Name:	San Francisco Bay Urban Creeks Diazinon
TMDL Project Code:	9
Date TMDL Approved by USEPA:	05/21/2007
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. NUMBER lines of evidence are available in the administrative record to assess this pollutant. NUMBER of the NUMBER samples exceed the OBJECTIVE/GUIDELINE/CRITERIA. 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. NUMBER of NUMBER samples exceed the OBJECTIVE/GUIDELINE/CRITERIA 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:	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 144624, Fipronil	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283873

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of fipronil does not exceed 0.0032 ug/L (3.2 ng/L) in the water column more than once every three years on average (Bower, et al. 2017).

Guideline Reference:

Water and Sediment Quality Criteria Report for Fipronil. Phase III: Application of the pesticide water and sediment quality criteria methodologies. Department of Environmental Toxicology, University of California, Davis.

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144624, Fipronil	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283939

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144624, Fipronil	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283936

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144624, Fipronil	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

283834

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	149126	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

Pollutant:	Indicator Bacteria
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
TMDL Name:	Sonoma Creek Pathogens
TMDL Project Code:	63
Date TMDL Approved by USEPA:	02/29/2008
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 2.2 and 3.3 of the Listing Policy. Under section 3.3 of the Policy, a minimum of one line of evidence is needed to assess listing status. Eight lines of evidence are available in the administrative record to assess this pollutant. Thirteen out of seventeen samples exceeded the geometric mean bacteria objective. 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 in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard. 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. Thirteen out of seventeen samples exceeded the geometric mean bacteria objective and these exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. The Sonoma Creek Pathogen TMDL was approved by USEPA in February 29, 2008. 5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be 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:	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 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300192

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use for waters where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2018-06-05 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300214

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2018-06-05 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300061

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 206NAT035 (Nathanson Creek at south boundary of AHMS).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2018-06-05 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

299938

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the days of 2017-02-07 and 2019-07-15 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300086

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the days of 2017-02-07 and 2019-07-15 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

299912

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT010 (Nathanson Creek at Watmaugh just west of 5th Street).

Temporal Representation:

The samples were collected between the days of 2017-02-07 and 2019-07-15 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300217

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the days of 2017-02-07 and 2019-07-15 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 149126, Indicator Bacteria	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300151

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

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): 206NAT040 (Nathanson Creek at north boundary of SVHS).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2018-06-05 .

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.


DECISION ID	144623	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

Pollutant:	Pyrethroids
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Other Urban Runoff \| Surface Runoff
TMDL Name:	San Francisco Bay Urban Creeks Diazinon
TMDL Project Code:	9
Date TMDL Approved by USEPA:	05/21/2007
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. Six lines of evidence are available in the administrative record to assess this pollutant. Two of the two total pyrethroid water samples exceed the evaluation guideline. 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. Two of two samples exceed the evaluation guideline 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:	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 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287648

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287668

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287724

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 Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287705

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206FRY001 (Fryer Creek at Leveroni Road).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287707

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

Data for this waterbody were collected over the date range 2017-11-16 to 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):

Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.

Line of Evidence (LOE) for Decision ID 144623, Pyrethroids	Region 2
Nathanson Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287685

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)

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: 206NAT030 (Nathanson Creek at Nathanson Park).

Temporal Representation:

The samples were collected between the dates of 2017-11-16 and 2018-11-23

Environmental Conditions:

QAPP Information:

Sonoma County Permit and Resource Management Department. 2019. Clean Streams in Southern Sonoma County (CS3C).

QAPP Information Reference(s):