| Water Body Name: | Oxbow Reservoir (Ralston Afterbay, El Dorado and Placer Counties) |
| Water Body ID: | CAL5144101020080922153913 |
| Water Body Type: | Lake & Reservoir |
DECISION ID |
131341 |
Region 5 |
Oxbow Reservoir (Ralston Afterbay, El Dorado and Placer Counties) |
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| Pollutant: | Mercury |
| Final Listing Decision: | Delist from 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2018) |
| Revision Status | Revised |
| Reason for Delisting: | Applicable WQS attained; due to change in WQS |
| Expected TMDL Completion Date: | 2021 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. LOE 22578 is replaced with LOEs 227433 and 227450. The replacement LOEs are a reassessment of the same data following the statewide mercury objectives adopted in 2017. WILD beneficial use (sport fish objective): LOE 227450: 0 of 1 samples exceed the mercury objective and consist of 9 trophic level 4 fish. COMM beneficial use (sport fish objective): LOE 227433: 0 of 1 samples exceed the mercury objective and consist of 9 trophic level 4 fish. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 1 sample exceeds the objective for the WILD beneficial use. 0 of 1 sample exceeds the objective for the COMM beneficial use. 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 227450 | ||||
| Pollutant: | Mercury | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | Fish fillet | ||||
| Beneficial Use: | Wildlife Habitat | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Middle Fork American River Project AQ11 data for Oxbow Reservoir (Ralston Afterbay, El Dorado and Placer Counties) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 9 fish were aggregated into 1 annual averages, which consisted of 2 fish species (5 composite(s) of Sacramento Pikeminnow each composed of 1 fish per composite, 4 composite(s) of Brown Trout each composed of 1 fish per composite). | ||||
| Data Reference: | Middle Fork American River Project AQ11 Water Quality Technical Study Report, 2007 (FERC No. 2079). Placer County Water Agency. June 2008 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. (Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins) | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed | ||||
| Evaluation Guideline: | The Statewide Sport Fish Water Quality Objective for the protection of Wildlife Habitat comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. If trophic level 3 fish are used in the assessment then the Prey Fish Water Quality Objective must also be used to determine that the Sport Fish Objective is being met. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027. | ||||
| Guideline 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 | ||||
| Spatial Representation: | Data was collected from 1 station(s) with the station code(s): Ralston Afterbay. | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2007-09-14 and 2007-09-14. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data quality: Good. Quality Control for the fish sampling, tissue preparation and mercury analysis portions of this study was conducted in accordance with the AQ-11 Water Quality Technical Study Plan (PCWA, 2007). | ||||
| QAPP Information Reference(s): | Middle Fork American River Project AQ11 Water Quality Technical Study Report, 2007 (FERC No. 2079). Placer County Water Agency. June 2008 | ||||
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| LOE ID: | 227433 | ||||
| Pollutant: | Mercury | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | Fish fillet | ||||
| Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Middle Fork American River Project AQ11 data for Oxbow Reservoir (Ralston Afterbay, El Dorado and Placer Counties) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 9 fish were aggregated into 1 annual averages, which consisted of 2 fish species (5 composite(s) of Sacramento Pikeminnow each composed of 1 fish per composite, 4 composite(s) of Brown Trout each composed of 1 fish per composite). | ||||
| Data Reference: | Middle Fork American River Project AQ11 Water Quality Technical Study Report, 2007 (FERC No. 2079). Placer County Water Agency. June 2008 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. (Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins) | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed | ||||
| Evaluation Guideline: | The Statewide Sport Fish Water Quality Objective for the protection of the Commercial and Sport Fishing beneficial comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027. | ||||
| Guideline 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 | ||||
| Spatial Representation: | Data was collected from 1 station(s) with the station code(s): Ralston Afterbay. | ||||
| Temporal Representation: | Data for this line of evidence were collected between 2007-09-14 and 2007-09-14. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data quality: Good. Quality Control for the fish sampling, tissue preparation and mercury analysis portions of this study was conducted in accordance with the AQ-11 Water Quality Technical Study Plan (PCWA, 2007). | ||||
| QAPP Information Reference(s): | Middle Fork American River Project AQ11 Water Quality Technical Study Report, 2007 (FERC No. 2079). Placer County Water Agency. June 2008 | ||||