| Pollutant: |
Nutrients |
| Final Listing Decision: |
Do Not Delist from 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
Do Not Delist from 303(d) list (TMDL required list)(2018) |
| Revision Status |
Revised |
| Sources: |
Agriculture | Onsite Wastewater Systems (Septic Tanks) |
| Expected TMDL Completion Date: |
2037 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Regional Board Conclusion: |
Region 2 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. |
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| Regional Board Decision Recommendation: |
This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current. The decision has not changed. |
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| State Board Review of Regional Board Conclusion and Recommendation: |
|
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| State Board Decision Recommendation: |
After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| Pollutant: |
Indicator Bacteria |
| Final Listing Decision: |
Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Sources: |
Onsite Wastewater Systems (Septic Tanks) |
| TMDL Name: |
Sonoma Creek Pathogens |
| TMDL Project Code: |
63 |
| Date TMDL Approved by USEPA: |
02/29/2008 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Regional Board Conclusion: |
The pollutant name was changed from Pathogens to Indicator Bacteria in the 2024 Integrated Report but no new data were assessed. The Pathogen decision (ID 87100) was retired.
303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed. A TMDL has been developed and approved by USEPA (2/29/2008) and an approved implementation plan is expected to result in attainment of the standard. This provides a sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list. |
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| Regional Board Decision Recommendation: |
This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed. The pollutant name was changed from Pathogens to Indicator Bacteria in the 2024 Integrated Report. The Pathogen decision (ID 87100) was retired. |
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| State Board Review of Regional Board Conclusion and Recommendation: |
|
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| State Board Decision Recommendation: |
After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| Pollutant: |
Toxicity |
| Final Listing Decision: |
Do Not List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| 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 |
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| 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. |
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| State Board Review of Regional Board Conclusion and Recommendation: |
|
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| 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. |
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Line of Evidence (LOE) for Decision ID 143400, Toxicity
|
Region 2 |
Sonoma Creek, tidal |
|
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| LOE ID: |
269092 |
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| Pollutant: |
Toxicity |
| LOE Subgroup: |
Toxicity |
| Matrix: |
Sediment |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
7 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
TOXICITY TESTING |
| Data Used to Assess Water Quality: |
0 of the 7 samples collected by SWAMP Stream Pollution Trends for Sonoma Creek, tidal exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca for Growth (wt/surv indiv), Hyalella azteca for Survival, Chironomus dilutus for Growth (wt/surv indiv), Chironomus dilutus for Survival. |
| Data Reference: |
Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. |
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| SWAMP Data: |
SWAMP |
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| Water Quality Objective/Criterion: |
All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce other detrimental responses in aquatic organisms. Detrimental responses include, but are not limited to, decreased growth rate and decreased reproductive success of resident or indicator species. There shall be no acute toxicity in ambient waters. Acute toxicity is defined as a median of less than 90 percent survival, or less than 70 percent survival, 10 percent of the time, of test organisms in a 96-hour static or continuous flow test. There shall be no chronic toxicity in ambient waters. Chronic toxicity is a detrimental biological effect on growth rate, reproduction, fertilization success, larval development, population abundance, community composition, or any other relevant measure of the health of an organism, population, or community. Attainment of this objective will be determined by analyses of indicator organisms, species diversity, population density, growth anomalies, or toxicity tests (including those described in Chapter 4), or other methods selected by the Water Board. The Water Board will also consider other relevant information and numeric criteria and guidelines for toxic substances developed by other agencies as appropriate. |
| Objective/Criterion Reference: |
Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) |
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| Evaluation Guideline: |
The sample is toxic when the response of the organisms exposed to the sample is significantly different (worse) than the response of the organisms exposed to the laboratory control based on statistical hypothesis testing. An exceedance is counted when the significant effect code is “Significant; Less Similarity,” which means that the sample result is significantly different than the control result, and the percent effect is greater than the evaluation threshold. The default evaluation threshold is 20% unless otherwise stated. |
| Guideline Reference: |
Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013 |
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| Spatial Representation: |
The samples were collected at monitoring site: 206SON010 ( Sonoma Creek at Hwy 121 bridge ). |
| Temporal Representation: |
The samples were collected between the dates of 2011-07-07 and 2020-07-15. |
| 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. |
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Line of Evidence (LOE) for Decision ID 143400, Toxicity
|
Region 2 |
Sonoma Creek, tidal |
|
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| LOE ID: |
269093 |
| |
| Pollutant: |
Toxicity |
| LOE Subgroup: |
Toxicity |
| Matrix: |
Sediment |
| Fraction: |
None |
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| Beneficial Use: |
Cold Freshwater Habitat |
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| Number of Samples: |
7 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
TOXICITY TESTING |
| Data Used to Assess Water Quality: |
0 of the 7 samples collected by SWAMP Stream Pollution Trends for Sonoma Creek, tidal exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca for Growth (wt/surv indiv), Hyalella azteca for Survival, Chironomus dilutus for Growth (wt/surv indiv), Chironomus dilutus for Survival. |
| Data Reference: |
Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2. |
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| SWAMP Data: |
SWAMP |
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| Water Quality Objective/Criterion: |
All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce other detrimental responses in aquatic organisms. Detrimental responses include, but are not limited to, decreased growth rate and decreased reproductive success of resident or indicator species. There shall be no acute toxicity in ambient waters. Acute toxicity is defined as a median of less than 90 percent survival, or less than 70 percent survival, 10 percent of the time, of test organisms in a 96-hour static or continuous flow test. There shall be no chronic toxicity in ambient waters. Chronic toxicity is a detrimental biological effect on growth rate, reproduction, fertilization success, larval development, population abundance, community composition, or any other relevant measure of the health of an organism, population, or community. Attainment of this objective will be determined by analyses of indicator organisms, species diversity, population density, growth anomalies, or toxicity tests (including those described in Chapter 4), or other methods selected by the Water Board. The Water Board will also consider other relevant information and numeric criteria and guidelines for toxic substances developed by other agencies as appropriate. |
| Objective/Criterion Reference: |
Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) |
| |
| Evaluation Guideline: |
The sample is toxic when the response of the organisms exposed to the sample is significantly different (worse) than the response of the organisms exposed to the laboratory control based on statistical hypothesis testing. An exceedance is counted when the significant effect code is “Significant; Less Similarity,” which means that the sample result is significantly different than the control result, and the percent effect is greater than the evaluation threshold. The default evaluation threshold is 20% unless otherwise stated. |
| Guideline Reference: |
Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013 |
| |
| Spatial Representation: |
The samples were collected at monitoring site: 206SON010 ( Sonoma Creek at Hwy 121 bridge ). |
| Temporal Representation: |
The samples were collected between the dates of 2011-07-07 and 2020-07-15. |
| 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. |
| |
| Pollutant: |
Sedimentation/Siltation |
| Final Listing Decision: |
Delist from 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
Delist from 303(d) list (TMDL required list)(2016) |
| Revision Status |
Original |
| Reason for Delisting: |
Delisting due to spatial change or other CalWQA administrative reason |
| Impairment from Pollutant or Pollution: |
Pollutant |
| |
| Regional Board Conclusion: |
De-listing due to a mapping change. The listing for sediment Sonoma Creek originated from fine sediment impacts to spawning and rearing habitat as noted in the TMDL. The TMDL provides actions to reduce fine sediment input to the non-tidal portion of the main stem and all freshwater tributaries. When Sonoma Creek was a single water body segment, the impairment and TMDL applied to entire main stem segment. Now that we have separated Sonoma Creek into tidal and non-tidal segments for the Integrated Report purposes, we removed the listing for sediment from the tidal segment to be consistent with the impairment analyses and implementation actions required in the TMDL. |
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| Regional Board Decision Recommendation: |
After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded. |
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| State Board Review of Regional Board Conclusion and Recommendation: |
|
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| State Board Decision Recommendation: |
After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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