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

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name:	Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)
Water Body ID:	CAR2064001020210705040916
Water Body Type:	River & Stream


DECISION ID	144849	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 144849, Alkalinity as CaCO3	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

276832

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the San Francisco Bay Basin: Controllable water quality factors shall not cause a detrimental increase in concentrations of toxic substances found in bottom sediments or aquatic life. Effects on aquatic organisms, wildlife, and human health will be considered.

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2012-08-16 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144849, Alkalinity as CaCO3	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

276931

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2012-08-16 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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


DECISION ID	150936	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 150936, Ammonia	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

279479

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, San Francisco Bay Basin, Chapter III Water Quality Objectives, Section 3.3.20 Un-Ionized Ammonia: The discharge of wastes shall not cause receiving waters to contain concentrations of un-ionized ammonia in excess 0.025 mg/l (as N), expressed as an annual median.

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2012-08-16 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150936, Ammonia	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

279945

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2012-08-16 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150936, Ammonia	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

278376

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 150936, Ammonia	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

278811

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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


DECISION ID	144844	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 144844, Chloride	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

281347

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Chloride.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144844, Chloride	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

281450

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Chloride.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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


DECISION ID	144847	Region 2
Frey 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:

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298765

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:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298928

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:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298841

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:

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

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: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298702

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:

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

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: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298909

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:

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

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: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288860

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:

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

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:

Inland Fishes of California

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

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-03 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288986

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288842

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288875

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288619

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

SWAMP Data:

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288598

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

288911

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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:

Inland Fishes of California

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298833

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:

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

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: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144847, Temperature, water	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

298834

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:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Temperature.

Data Reference:

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

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: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-10 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)


DECISION ID	144848	Region 2
Frey 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 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289817

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:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302854

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

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: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302901

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:

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

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: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302856

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:

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

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: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302814

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:

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

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: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289268

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:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289662

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:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302890

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:

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

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: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302855

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289382

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:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-10 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

302886

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

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: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-10 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289876

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:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289453

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:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Turbidity.

Data Reference:

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

SWAMP Data:

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144848, Turbidity	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

289628

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:

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

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:

Inland Fishes of California

Spatial Representation:

The samples were collected at 1 monitoring site: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)


DECISION ID	144846	Region 2
Frey 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:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286381

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286858

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for pH.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286895

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287001

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286817

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

286837

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-26 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144846, pH	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

287003

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for pH.

Data Reference:

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

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: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-10 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)


DECISION ID	144845	Region 2
Frey 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. Nine of the thirty-one samples exceed the Basin Plan's 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. Nine of the thirty-one samples exceed the Basin Plan's 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:

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285005

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285270

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285887

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284912

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 4 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285029

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285224

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285305

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

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: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-03 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285886

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285019

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 1 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284887

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the dates of 2019-07-03 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

284890

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 1 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285243

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285316

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB2 Monitoring data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

SWAMP Data:

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: 206HMC030 (Hood Mountain Creek at Lawndale Ave.).

Temporal Representation:

The samples were collected between the dates of 2011-08-08 and 2012-08-16

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 144845, Oxygen, Dissolved	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

285885

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

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

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: 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the dates of 2019-06-19 and 2019-07-17

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)


DECISION ID	149324	Region 2
Frey 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:	See TMDL documentation
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 section 3.11 of the Listing Policy. Under this section when all other listing factors do not result in the listing of a water segment but information indicates non-attainment of standards, a water segment shall be evaluated to determine whether the weight of evidence demonstrates that water quality standard is not attained. If the weight of evidence indicates non-attainment, the water segment shall be placed on the CWA section 303(d) List. When making a listing decision based on the situation-specific weight of evidence, the Regional Water Board must justify its recommendation by: • Providing any data or information including current conditions supporting the decision; • Describing in fact sheets how the data or information affords a substantial basis in fact from which the decision can be reasonably inferred; • Demonstrating that the weight of evidence of the data and information indicate that the water quality standard is not attained; and • Demonstrating that the approach used is scientifically defensible and reproducible. Frey Creek is a tributary to Sonoma Creek. The Sonoma Creek and its tributaries, including Frey Creek, are impaired by indicator bacteria (pathogens) and subject to the Sonoma Creek Pathogen TMDL. The weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA section 303(d) List, specifically on the being addressed portion of the CWA section 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. Frey Creek is a tributary to Sonoma Creek which is impaired by pathogens. E. coli measured at several Sonoma Creek watershed locations during the development of the Sonoma Creek Pathogen TMDL showed moderate but widespread exceedances of water quality objectives, indicating pathogen impairment of REC-1 and REC-2 beneficial uses throughout the watershed. The sources of pathogens, such as onsite wastewater treatment systems, confined animal facilities, grazing lands and municipal runoff exist throughout the Sonoma Creek watershed, including the Frey Creek watershed. 2. The Sonoma Creek implementation plan states “The overall intent of this implementation plan is to restore and protect beneficial uses of Sonoma Creek and its tributaries by reducing pathogen loadings. Potential pathogen sources in the watershed include: septic systems, sanitary sewer system failures, municipal runoff, livestock grazing, and dairies.” The TMDL implementation actions (e.g., the Conditional Waiver Program from Grazing Operations and the NPDES general stormwater permit), were written to include the entire Sonoma Creek watershed. As such, the Sonoma Creek Pathogen TMDL already applies to the Frey Creek subwatershed. Sources of pathogens exist in the Frey Creek subwatershed and contribute to exceedances of E.coli objectives for water contact recreation. 3. The most severe and consistent exceedances of the E.coli objectives were observed in downstream Sonoma Creek and in the town of Sonoma neighboring Frey Creek. Exceedance frequency of E.coli geomean increased 10 percent during the post-TMDL wet season sampling. The water quality data are insufficient to determine that water quality have been improved and water quality objectives are met in the Sonoma Creek watershed in general and in Frey Creek subwatershed in particular. Therefore, based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the being addressed portion of the CWA section 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. 4. This process is scientifically defensible and reproducible. The Frey Creek subwatershed was part of the Sonoma Creek Pathogen TMDL assessment. The TMDL assessment included a rigorous technical review, the public participation process, and approval by U.S. EPA. Additionally, the data analysis for the TMDL made use of the E. coli objectives that were in place at the time of TMDL development. Although these objectives have been subsequently updated, exceedances of the older objectives would also constitute exceedances of the revised (lower) objectives.

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:	Therefore, based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the being addressed portion of the CWA section 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. 4. This process is scientifically defensible and reproducible. The Frey Creek subwatershed was part of the Sonoma Creek Pathogen TMDL assessment. The TMDL assessment included a rigorous technical review, the public participation process, and approval by U.S. EPA. Additionally, the data analysis for the TMDL made use of the E. coli objectives that were in place at the time of TMDL development. Although these objectives have been subsequently updated, exceedances of the older objectives would also constitute exceedances of the revised (lower) objectives.

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 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300128

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 2 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300126

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300172

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

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

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): 206FRE002 (Frey Tributary above Felton Tributary Confluence).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300170

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FRE006 (Frey Tributary at Oakmont Dr Bridge).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300042

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

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

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): 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300218

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

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

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): 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300084

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FRE003 (Frey Tributary Below Lawndale Rd Bridge).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

299914

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

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

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): 206FRE004 (Frey Tributary above Frey Rd Private Bridge).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300152

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FRE006b (Frey DS of Oakmont pumping station near back limit of 8810 Oakmont Dr).

Temporal Representation:

The samples were collected between the days of 2019-07-03 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)

Line of Evidence (LOE) for Decision ID 149324, Indicator Bacteria	Region 2
Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek)

LOE ID:

300193

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Clean Streams in S. SoCo Pathogen Source Detection data for Frey Creek subwatershed (Sonoma County, tributary to Sonoma Creek) to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

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

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): 206FEL001 (Felton Creek above confluence with Frey Creek).

Temporal Representation:

The samples were collected between the days of 2019-06-19 and 2019-07-17 .

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Clean Streams in Southern Sonoma County (CS3C)