Draft California 2026 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name:	Trinidad HU, Big Lagoon HA, Freshwater Lagoon
Water Body ID:	CAW1081000020230531032647
Water Body Type:	Wetland, Freshwater


DECISION ID	158363	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

Pollutant:	PCBs (Polychlorinated biphenyls)
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 158363, PCBs (Polychlorinated biphenyls)	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322717

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

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 North Coast Region)

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for polychlorinated biphenyls in fish tissue is 2.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Data for this line of evidence were collected between 2016-07-19 and 2016-07-19. 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:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 158363, PCBs (Polychlorinated biphenyls)	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322724

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

National Academy of Science guidelines (NAS 1972) establish a maximum total PCB Arochlor concentration of 500 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 158363, PCBs (Polychlorinated biphenyls)	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322707

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Marine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 158363, PCBs (Polychlorinated biphenyls)	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322702

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	158364	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

Pollutant:	Selenium
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 158364, Selenium	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322748

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 0 of 4 samples exceeded the water quality threshold for Selenium. Monitors collected 5 composites: 2 composites of Hitch composed of 5 fish each, 1 composite of Largemouth Bass composed of 5 fish, 1 composite of Largemouth Bass composed of 10 fish, and 1 composite of Silverside composed of 10 fish. Because 2 or more composites were collected within the same averaging period, these composites resulted in 4 independent samples.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

The OEHHA Fish Contaminant Goal for selenium in fish tissue is 7.4 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A background dietary consumption rate of 0.114 mg/day is applied for this micronutrient. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170549	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

Pollutant:	Mercury
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
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.11 of the Listing Policy. Under section 3.11 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. Five lines of evidence are available in the administrative record to assess the pollutant. COMM (Sport fish objective) Fish used in the COMM assessment are limited to lengths that are within Calif. Dept. of Fish and Wildlife legal size limits applicable to this waterbody. LOE 322664: 1 of 1 samples exceed the mercury objective and consist of 11 trophic level 4 fish. (CDFW legal limit) MAR (Prey fish objective) LOE 322623: 1 of 1 samples exceed the mercury objective and consist of 30 50-150 mm prey fish. MAR (Sport fish objective) LOE 322635: 1 of 1 samples exceed the mercury objective and consist of 11 trophic level 4 fish. (CDFW legal limit) WILD (Prey fish objective) LOE 322686: 1 of 1 samples exceed the mercury objective and consist of 30 50-150 mm prey fish. WILD (Sport fish objective) LOE 322668: 1 of 1 samples exceed the mercury objective and consist of 11 trophic level 4 fish. (CDFW legal limit) 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. Tissue samples were compared with the sport fish objective and 1 of 1 samples exceed for the WILD beneficial use, 1 of 1 exceed for the MAR beneficial use, and 1 of 1 samples exceed for the COMM beneficial use. The samples consist of trophic level 4 fish that are annual averages and are aggregated from at least eight fish and this meets the one exceeding sample of eight or more fish needed to determine non-attainment of the mercury objective following weight of evidence in Listing Policy section 3.11. 4. Tissue samples were compared with the prey fish objective and 1 of 1 samples exceed WILD beneficial use and 1 of 1 samples exceed MAR beneficial use. The exceeding sample, which may contain a mix of trophic levels, is aggregated from at least eight fish and this meets the one exceeding sample of eight or more fish needed to determine non-attainment of the mercury objective following weight of evidence in Listing Policy section 3.11. 5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. This listing applies to the entire waterbody.

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:	Decision written by SWRCB staff.

Line of Evidence (LOE) for Decision ID 170549, Mercury	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322635

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Marine 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 Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 11 composites of Largemouth Bass composed of 1 fish each. This LOE contains data only for trophic level 4 fish whose average length was inside the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations. Fish collected within the same calendar year were averaged into a single sample for comparison with the objective. All 11 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2016.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

The Statewide Sport Fish Water Quality Objective for the protection of Marine 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 were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170549, Mercury	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322668

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Wildlife 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 Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 11 composites of Largemouth Bass composed of 1 fish each. This LOE contains data only for trophic level 4 fish whose average length was inside the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations. Fish collected within the same calendar year were averaged into a single sample for comparison with the objective. All 11 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2016.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

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 were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170549, Mercury	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322664

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:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 11 composites of Largemouth Bass composed of 1 fish each. This LOE contains data only for trophic level 4 fish whose average length was inside the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations. Fish collected within the same calendar year were averaged into a single sample for comparison with the objective. All 11 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2016.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

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 were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170549, Mercury	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322686

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Wildlife 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 Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 3 composites: 2 composites of Hitch composed of 5 fish each, 1 composite of Largemouth Bass composed of 10 fish, and 1 composite of Silverside composed of 10 fish. All fish collected between February and July of the same calendar year with a reported length of 50-150 mm were averaged into a single sample, independent of species or trophic level, for comparison with the objective. All 30 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2016.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

The Statewide Prey 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 0.05 mg/Kg wet weight whole fish samples of any fish species between 50 to 150 mm in total length collected between February 1 and July 31. (SWRCB 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 were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170549, Mercury	Region 1
Trinidad HU, Big Lagoon HA, Freshwater Lagoon

LOE ID:

322623

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Marine 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 Sportfish Contamination in Lakes and Resrv data for Trinidad HU, Big Lagoon HA, Freshwater Lagoon to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 3 composites: 2 composites of Hitch composed of 5 fish each, 1 composite of Largemouth Bass composed of 10 fish, and 1 composite of Silverside composed of 10 fish. All fish collected between February and July of the same calendar year with a reported length of 50-150 mm were averaged into a single sample, independent of species or trophic level, for comparison with the objective. All 30 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2016.

Data Reference:

Habitat, Tissue, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

The Statewide Prey Fish Water Quality Objective for the protection of Marine Habitat comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.05 mg/Kg wet weight whole fish samples of any fish species between 50 to 150 mm in total length collected between February 1 and July 31. (SWRCB 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 were collected from 1 station(s). Station Code(s): 108FRWLAG (Freshwater Lagoon).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP