| Water Body Name: | Suisun Slough |
| Water Body ID: | CAE2072300020020315202246 |
| Water Body Type: | Estuary |
DECISION ID |
141169 |
Region 2 |
Suisun Slough |
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| Pollutant: | Chlorine |
| 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. |
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| LOE ID: | 282301 | ||||
| Pollutant: | Chlorine | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Estuarine Habitat | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BASMAA RMC Monitoring in WY2017 data for Suisun Slough to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Chlorine, Total Residual. | ||||
| Data Reference: | Field, Habitat, Toxicity, 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 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 chlorine criterion for the protection of aquatic life in saline water is 7.5 ug/L (4-day average). | ||||
| Guideline Reference: | National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016. | ||||
| Spatial Representation: | The samples were collected at 1 monitoring site: 207SSL010 (Suisun Slough at Marina). | ||||
| Temporal Representation: | The samples were collected between the dates of 2017-08-29 and 2017-08-29 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | EOA, Inc., Applied Marine Sciences, Armand Ruby Consulting . 2016. BASMAA Regional Monitoring Coalition Creek Status and Pesticides & Toxicity Monitoring Quality Assurance Project Plan. | ||||
| QAPP Information Reference(s): | BASMAA Regional Monitoring Coalition Creek Status and Pesticides & Toxicity Monitoring Quality Assurance Project Plan | ||||
DECISION ID |
148821 |
Region 2 |
Suisun Slough |
||
| Pollutant: | Indicator Bacteria |
| Final Listing Decision: | Do Not List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| Revision Status | Revised |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of 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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| LOE ID: | 299819 | ||||
| Pollutant: | Fecal Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | 90th percentile | ||||
| Beneficial Use: | Non-Contact Recreation | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BASMAA RMC Monitoring in WY2017 data for Suisun Slough to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 30-day 90% percentile. | ||||
| Data Reference: | Field, Habitat, Toxicity, 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 3.3.1 Bacteria: Table 3-1 provides a summary of the bacterial water quality objectives and identifies the sources of those objectives. The fecal coliform objective for non-contact recreation is a 30-day 90th percentile less than 4000 MPN/100 ML. | ||||
| 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(s), station(s): 207SSL010 (Suisun Slough at Marina). | ||||
| Temporal Representation: | The samples were collected between the days of 2017-08-29 and 2017-08-29 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | EOA, Inc., Applied Marine Sciences, Armand Ruby Consulting . 2016. BASMAA Regional Monitoring Coalition Creek Status and Pesticides & Toxicity Monitoring Quality Assurance Project Plan. | ||||
| QAPP Information Reference(s): | BASMAA Regional Monitoring Coalition Creek Status and Pesticides & Toxicity Monitoring Quality Assurance Project Plan | ||||
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| LOE ID: | 299699 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | STV | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BASMAA RMC Monitoring in WY2019 data for Suisun Slough 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 Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Field, Habitat, Toxicity, 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 1 ppth or higher 95 percent or more of the time applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in 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): 207SSL010 (Suisun Slough at Marina). | ||||
| Temporal Representation: | The samples were collected between the days of 2019-08-20 and 2019-08-20 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | EOA, Inc.. 2014. Creek Status Monitoring Program Quality Assurance Project Plan. | ||||
| QAPP Information Reference(s): | Creek Status Monitoring Program Quality Assurance Project Plan | ||||
DECISION ID |
151435 |
Region 2 |
Suisun Slough |
||
| Pollutant: | Temperature, water |
| 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: | 2038 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Of these lines of evidence, 1 are based on continuous monitoring data and 0 are based on grab sample data. Continuous temperature data were used as the primary source of evidence for this assessment. A rolling 7-Day Average of Daily Maximum (7DADM) was calculated for all available data and a 7DADM is evaluated as a single sample. In the absence of natural or historical temperature data, the samples were compared against USEPA Region 10 recommended temperature requirements for each appropriate salmonid life stage present in the waterbody segment (Listing Policy Section 6.1.5.9). The evaluation guideline was applied during the smolt migration (20 degrees Celsius between March 15 – June 15) and adult migration (20 degrees Celsius between September 1 – December 31) salmonid life stages. A total of 490 of 1787 samples exceed the evaluation guideline (USEPA 2003) applied to protect the migration (MIGR) freshwater habitat beneficial use. 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. 490 of 1787 samples exceed the MIGR evaluation guideline for the 7DADM 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: | This decision was made by SWRCB staff. |
| 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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem. |
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| LOE ID: | 306027 | ||||
| Pollutant: | Temperature, water | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Fish Migration | ||||
| Number of Samples: | 1787 | ||||
| Number of Exceedances: | 490 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Data collected hourly from 1986 through 2019 at station GOD (GODFATHER II ON SUISUN SLOUGH). The data was provided by staff at the CA Department of Water Resources for the Interagency Ecological Program. Only data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. The 7-DADM temperatures were computed for the contiguous 7-day periods available during this time frame. The 7-day average of maximum daily temperature exceeded the evaluation guideline during 490 of the 1787 7-day periods. | ||||
| Data Reference: | Hourly water temperature from the San Francisco Estuary, 1986 - 2019 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | 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: | A 7-day average of daily maximum (7-DADM) temperature of 20 degrees Celsius is recommended by the USEPA for waterbodies that are used almost exclusively for migration during the period of summer maximum temperatures to protect migrating juveniles and adults from lethal temperatures (USEPA, 2003). This evaluation guideline was applied to both the smolt (March 15 - June 15) and adult (September 1 - December 31) migration periods. | ||||
| Guideline Reference: | EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. U.S. Environmental Protection Agency Region 10 Office of Water, Seattle, WA. | ||||
| Spatial Representation: | Data collected from CA Department of Water Resources Station GOD (GODFATHER II ON SUISUN SLOUGH). | ||||
| Temporal Representation: | Data collected hourly from 1986 through 2019. Data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | The data were collected by the CA Department of Water Resources' Division of Environmental Services and were deemed by the DWR to be reliable and of sound quality. Information about the monitoring equipment used is available in the reference. | ||||
| QAPP Information Reference(s): | California Department of Water Resources (CDWR) Continuous Temperature QAPP. | ||||
DECISION ID |
100850 |
Region 2 |
Suisun Slough |
||
| Pollutant: | Mercury |
| 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: | Historic Land Management Activities |
| TMDL Name: | Suisun Marsh Dissolved Oxygen and Mercury TMDL |
| TMDL Project Code: | 553 |
| Date TMDL Approved by USEPA: | 12/31/2018 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Suisun Slough is part of the Suisun Marsh system. As such, the impairments for Suisun Marsh are applicable to sloughs within the marsh. Further, the TMDL for Suisun Marsh will resolve the impairments for sloughs within the Suisun Marsh system. Accordingly, the mercury impairment in Suisun Slough will be addressed and resolved by the Suisun Marsh TMDL for dissolved oxygen approved by USEPA on 12/31/2018. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 125246 | ||||
| Pollutant: | Mercury | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Estuarine Habitat | ||||
| Number of Samples: | 0 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | Not Specified | ||||
| Data Used to Assess Water Quality: | This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh | ||||
| Data Reference: | Staff Report for Proposed Basin Plan Amendment - Establish Water Quality Objectives and a Total Maximum Daily Load for Dissolved Oxygen in Suisun Marsh and add Suisun Marsh to the SF Bay Mercury TMDL | ||||
| SWAMP Data: | |||||
| Water Quality Objective/Criterion: | This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh. This placeholder LOE will fulfill database requirements to create a listing for Suisun Slough. This slough listing will subsequently be associated with the TMDL for Suisun Marsh - which aims to resolve the mercury and low DO/organic enrichment impairments. Suisun Slough is part of the Suisun Marsh system so resolution of the Suisun Marsh impairments will resolve those in Suisun Slough as well. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | |||||
| Temporal Representation: | |||||
| Environmental Conditions: | |||||
| QAPP Information: | This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh. | ||||
| QAPP Information Reference(s): | |||||
DECISION ID |
100851 |
Region 2 |
Suisun Slough |
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| Pollutant: | Oxygen, Dissolved |
| 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: | Historic Land Management Activities |
| TMDL Name: | Suisun Marsh Dissolved Oxygen and Mercury TMDL |
| TMDL Project Code: | 553 |
| Date TMDL Approved by USEPA: | 12/31/2018 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Suisun Slough is part of the Suisun Marsh system. As such, the impairments for Suisun Marsh are applicable to sloughs within the marsh. Further, the TMDL for Suisun Marsh will resolve the impairments for sloughs within the Suisun Marsh system. Accordingly, the dissolved oxygen impairment in Suisun Slough will be addressed and resolved by the Suisun Marsh TMDL for dissolved oxygen approved by USEPA on 12/31/2018. We should note that the impairment for Suisun Marsh was originally for organic enrichment/low dissolved oxygen. While this original pollutant description is the most accurate, the impairment for this slough is given as low dissolved oxygen. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 125375 | ||||
| Pollutant: | Oxygen, Dissolved | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Estuarine Habitat | ||||
| Number of Samples: | 0 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | Not Specified | ||||
| Data Used to Assess Water Quality: | This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh | ||||
| Data Reference: | Staff Report for Proposed Basin Plan Amendment - Establish Water Quality Objectives and a Total Maximum Daily Load for Dissolved Oxygen in Suisun Marsh and add Suisun Marsh to the SF Bay Mercury TMDL | ||||
| SWAMP Data: | |||||
| Water Quality Objective/Criterion: | This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh. This placeholder LOE will fulfill database requirements to create a listing for Suisun Slough. This slough listing will subsequently be associated with the TMDL for Suisun Marsh - which aims to resolve the mercury and low DO/organic enrichment impairments. Suisun Slough is part of the Suisun Marsh system so resolution of the Suisun Marsh impairments will resolve those in Suisun Slough as well. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | |||||
| Temporal Representation: | |||||
| Environmental Conditions: | |||||
| QAPP Information: | This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh | ||||
| QAPP Information Reference(s): | |||||
DECISION ID |
69483 |
Region 2 |
Suisun Slough |
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| Pollutant: | Diazinon |
| Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL) |
| Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2016) |
| Revision Status | Original |
| Sources: | A Source Unknown |
| TMDL Name: | San Francisco Bay Urban Creeks Diazinon |
| TMDL Project Code: | 9 |
| Date TMDL Approved by USEPA: | 05/16/2007 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | 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. The USEPA final decision on the 2006 303(d) list was to move this listing to the being addressed by a USEPA approved TMDL portion of the 303(d) list, because the San Francisco Bay Urban Creeks Diazinon TMDL was approved by USEPA on 5/16/07 (USEPA, 2007). |
| Regional Board Decision Recommendation: | This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current. The decision has not changed. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 473 | ||||
| Pollutant: | Diazinon | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 0 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | Not Specified | ||||
| Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006. | ||||
| Data Reference: | Placeholder reference 2006 303(d) | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | |||||
| Objective/Criterion Reference: | |||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | |||||
| Temporal Representation: | |||||
| Environmental Conditions: | |||||
| QAPP Information: | QA Info Missing | ||||
| QAPP Information Reference(s): | |||||