| Water Body Name: | Almaden Reservoir |
| Water Body ID: | CAL2054003020000304125701 |
| Water Body Type: | Lake & Reservoir |
DECISION ID |
145408 |
Region 2 |
Almaden Reservoir |
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| Pollutant: | Mercury |
| Final Listing Decision: | Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL) |
| Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2018) |
| Revision Status | Revised |
| Sources: | Inactive Mining | Mine Tailings |
| TMDL Name: | Guadalupe River Watershed Mercury |
| TMDL Project Code: | 11 |
| Date TMDL Approved by USEPA: | 06/01/2010 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2 and SECTION 4.1 of the Listing Policy. Under SECTION 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Twenty of the twenty samples exceeded the mercury in fish tissue objective and these exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 4. The Guadalupe River Watershed mercury TMDL was approved by USEPA on 6/1/2010. 5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 307409 | ||||
| Pollutant: | Mercury | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | Fish whole body | ||||
| Beneficial Use: | Wildlife Habitat | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | Fish tissue analysis | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed SWAMP RMP data for Almaden Reservoir to determine beneficial use support and results are as follows: 1 of 1 samples for trophic level 3 fish in the 5-15 cm size range exceed the Basin Plan's mercury fish tissue objective of 0.05 mg/kg to protect wildlife. | ||||
| Data Reference: | Habitat, Tissue, 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, Table 3-4A Water Quality Objectives for Mercury in Waters of the Guadalupe River Watershed states, for the protection of aquatic organisms and wildlife: the water quality objective for is 0.05 mg methylmercury/kg fish in the average wet weight concentration measured in whole trophic level 3 fish with lengths 5-15 cm. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Data for this line of evidence were collected in one location in Almaden Reservoir | ||||
| Temporal Representation: | Data were collected on one date: 9/24/2019 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | SWAMP Sportfish Contamination in Lakes and Reservoirs Project | ||||
| 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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| LOE ID: | 5739 | ||||
| Pollutant: | Mercury (tissue) | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | None | ||||
| Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms | ||||
| Number of Samples: | 20 | ||||
| Number of Exceedances: | 20 | ||||
| Data and Information Type: | Fish tissue analysis | ||||
| Data Used to Assess Water Quality: | The 20 fish tissue samples were collected in 2004 to support development of the Guadalupe River watershed mercury TMDL. The fish were all largemouth bass ranging in lengths from 330 to 500 mm and weighing between 520 and 2080 grams. The mercury concentrations ranged from 2.16 to 7.35 mg/kg. All 20 fish tissue samples exceeded the criterion. | ||||
| Data Reference: | Technical Memorandum 5.3.2 Data Collection Report, Volume II, prepared by TetraTech Inc. Prepared for Santa Clara Valley Water District. February 8, 2005 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The Basin Plan contains the following objective: Many pollutants can accumulate on particles, in sediment, or bioaccumulate in fish and other aquatic organisms. 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.
In 2001, U.S. EPA adopted a fish tissue methylmercury criterion of 0.3 mg/kg (in whole fish) for the protection of human health. |
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| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) - San Francisco Bay Region (Region 2) | ||||
| Objective/Criterion Reference: | Water Quality Criterion For The Protection of Human Health: Methylmercury 2002 303(d) List Update Reference # 87 | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | Water Quality Criterion For The Protection of Human Health: Methylmercury 2002 303(d) List Update Reference # 87 | ||||
| Spatial Representation: | These fish were caught throughout the reservoir, and fish of this size integrate spatially because they consume prey from a wide spatial range. | ||||
| Temporal Representation: | Fish tissue data were collected for this waterbody in late summer 2004. These adult fish integrate mercury concentrations over several years. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | There is a well-developed QA plan for these data Tetra Tech, Inc. (Tetra Tech) 2003. Technical Memorandum 7.4.2, Quality Assurance Plan, Prepared for Santa Clara Valley Water District. June 13. | ||||
| QAPP Information Reference(s): | Technical Memorandum 7.4.2, Quality Assurance Plan, Prepared for Santa Clara Valley Water District. June 13 | ||||
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| LOE ID: | 307410 | ||||
| Pollutant: | Mercury | ||||
| LOE Subgroup: | Pollutant-Tissue | ||||
| Matrix: | Tissue | ||||
| Fraction: | Fish whole body | ||||
| Beneficial Use: | Wildlife Habitat | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | Fish tissue analysis | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed SWAMP RMP data for Almaden Reservoir to determine beneficial use support and results are as follows: 1 of 1 samples for trophic level 3 fish in the 15-35 cm size range exceed the Basin Plan's mercury fish tissue objective of 0.1 mg/kg to protect wildlife. | ||||
| Data Reference: | Habitat, Tissue, 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, Table 3-4A Water Quality Objectives for Mercury in Waters of the Guadalupe River Watershed states, for the protection of aquatic organisms and wildlife: the water quality objective for is 0.1 mg methylmercury/kg fish in the average wet weight concentration measured in whole trophic level 3 fish with lengths 15-35 cm. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Data for this line of evidence were collected in one location in Almaden Reservoir | ||||
| Temporal Representation: | Data were collected on one date: 9/24/2019 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | SWAMP Sportfish Contamination in Lakes and Reservoirs Project | ||||
| QAPP Information Reference(s): | This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements. | ||||