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

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name:	Iron Gate Reservoir
Water Body ID:	CAL1053702320020720133707
Water Body Type:	Lake & Reservoir


DECISION ID	168457	Region 1
Iron Gate Reservoir

Pollutant:	Mercury
Final Listing Decision:	Do Not 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
Sources:	A Source Unknown
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.5 and 4.11 of the Listing Policy. Under section 4.5 a single line of evidence is necessary to assess listing status. Under section 4.11 when all other delisting factors do not result in the delisting of a water segment but information indicates attainment of standards, a water segment shall be evaluated to determine whether the weight of evidence demonstrates that water quality standard is attained. If the weight of evidence indicates attainment, the water segment shall be removed from the CWA section 303(d) List. Seven 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 133916: 1 of 1 samples exceed the mercury objective and consist of 2 trophic level 4 fish. (CDFW legal limit) LOE 132980: 1 of 1 samples exceed the mercury objective and consist of 14 trophic level 4 fish. (CDFW legal limit) LOE 322666: 1 of 1 samples exceed the mercury objective and consist of 7 trophic level 4 fish. (CDFW legal limit) WILD (Prey fish objective) LOE 322675: 0 of 1 samples exceed the mercury objective and consist of 40 50-150 prey fish. WILD (Sport fish objective) LOE 133917: 1 of 1 samples exceed the mercury objective and consist of 2 trophic level 4 fish. (CDFW legal limit) LOE 132933: 1 of 1 samples exceed the mercury objective and consist of 14 trophic level 4 fish. (CDFW legal limit) LOE 322669: 1 of 1 samples exceed the mercury objective and consist of 7 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 against 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. Tissue samples were compared with the sport fish objective and 3 of 3 samples exceed for WILD beneficial use and 3 of 3 samples exceed for the COMM beneficial use. The samples consist of trophic level 4 fish and are from a minimum of 2 annual averages and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 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 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:	This listing applies to the entire waterbody.

State Board Decision Recommendation:	Decision written by SWRCB staff.

Line of Evidence (LOE) for Decision ID 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

322666

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 Iron Gate Reservoir to determine beneficial use support and the results are as follows: 1 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 7 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 7 fish were collected in a single calendar year, which resulted in 1 independent sample. The exceeding sample was for 2017.

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): 105PIG154 (Iron Gate Reservoir).

Temporal Representation:

Data for this line of evidence were collected between 2017-08-14 and 2017-08-14. 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:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

322675

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 Iron Gate Reservoir to determine beneficial use support and the results are as follows: 0 of 1 sample exceeded the water quality threshold for Mercury. Monitors collected 4 composites: 1 composite of Black Crappie composed of 10 fish, 1 composite of Hitch composed of 10 fish, 1 composite of Largemouth Bass composed of 10 fish, and 2 composites of Redear Sunfish composed of 5 fish each. All fish collected within 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 40 fish were collected in a single calendar year, which resulted in 1 independent sample.

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): 105PIG154 (Iron Gate Reservoir).

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 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

322669

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:

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): 105PIG154 (Iron Gate Reservoir).

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 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

132933

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 Iron Gate Reservoir to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality standard 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 14 fish were aggregated into 1 annual averages, which consisted of 1 fish species (14 composite(s) of Largemouth Bass each composed of 1 fish per composite). Of these annual averages, 1 average(s), (Year(s): 2008) exceeded the objective.This LOE does not contain data from fish whos average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

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:

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): 105PIG154.

Temporal Representation:

Data for this line of evidence were collected between 2008-05-12 and 2008-05-12. 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:

Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

133916

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 Klamath Hydroelectric Project data for Iron Gate Reservoir to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality standard 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 2 composites of Largemouth Bass were were aggregated into 1 annual average that exceeded the objecctive. The target minimum size for largemouth bass was a minimum of 12 inches. This LOE does not contain data from fish whos average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.

Data Reference:

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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): Iron Gate Reservoir.

Temporal Representation:

Data for this line of evidence were collected during 2003.

Environmental Conditions:

QAPP Information:

Data was previously assessed without a QAPP. Data reassessed without a QAPP for consistency.

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

133917

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 Klamath Hydroelectric Project data for Iron gate Reservoir to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality standard 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 2 composites of Largemouth Bass were fish were aggregated into 1 annual average that exceeded the objective. The target minimum size for largemouth bass was a minimum of 12 inches.

Data Reference:

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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): Iron Gate Reservoir.

Temporal Representation:

Data for this line of evidence were collected during 2003.

Environmental Conditions:

QAPP Information:

Data was previously assessed without a QAPP. Data reassessed without a QAPP for consistency.

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 168457, Mercury	Region 1
Iron Gate Reservoir

LOE ID:

132980

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:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

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:

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): 105PIG154.

Temporal Representation:

Environmental Conditions:

QAPP Information:

Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	102597	Region 1
Iron Gate Reservoir

Pollutant:	Aldrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3 of the Listing Policy. Under section 3 a single line of evidence are necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. None of the samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 102597, Aldrin	Region 1
Iron Gate Reservoir

LOE ID:

44752

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Aldrin. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Cruise report for the Surface Water Ambient Monitoring Program (SWAMP) bioaccumulation screening study in California lakes and reservoirs year two (FY 07-08). Sampling dates: April 2008 - November 2008.

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Survey. A Report of the Surface Water Ambient Monitoring Program (SWAMP). California State Water Resources Control Board, Sacramento, CA

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. There shall be no bioaccumulation of pesticide concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, North Coast Basin)

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 Aldrin concentration of 100 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 for this line of evidence for Iron Gate Reservoir was collected at 1 monitoring site [ Iron Gate Reservoir - 105PIG154]. Samples were collected from 1 location. Individual sample locations consisted of an area within a given waterbody from which fish tissue samples were collected. The number of sample locations per waterbody was based on the overall size of the waterbody (SWAMP, 2010). Specifics of individual sampling locations can be found in the supplemental report entitled "Cruise Report for the Surface Waters Ambient Monitoring Program (SWAMP) Bioaccumulation Screening Study in California Lakes and Reservoirs, Sampling Dates: April 2008- November 2008" (SWAMP, 2009).

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Samples were collected, processed, and analyzed in accordance with the methods described in Quality Assurance Project Plan "Screening Study of Bioaccumulation in California Lakes and Reservoirs." (SWAMP, 2008).

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 102597, Aldrin	Region 1
Iron Gate Reservoir

LOE ID:

44751

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	157047	Region 1
Iron Gate Reservoir

Pollutant:	Alkalinity as CaCO3
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. The four 2026 LOEs (323039, 322939, 322940, 322957) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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 because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:	The four 2026 LOEs (323039, 322939, 322940, 322957) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157047, Alkalinity as CaCO3	Region 1
Iron Gate Reservoir

LOE ID:

322939

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 95 samples exceeded the water quality threshold for Alkalinity as CaCO3.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157047, Alkalinity as CaCO3	Region 1
Iron Gate Reservoir

LOE ID:

323039

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 1 of 95 samples exceeded the water quality threshold for Alkalinity as CaCO3.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157047, Alkalinity as CaCO3	Region 1
Iron Gate Reservoir

LOE ID:

322940

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. (Basin Plan, 2018)

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157047, Alkalinity as CaCO3	Region 1
Iron Gate Reservoir

LOE ID:

322957

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. (Basin Plan, 2018)

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	161408	Region 1
Iron Gate Reservoir

Pollutant:	Ammonia
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. The six 2026 LOEs (323552, 323291, 323426, 323497, 323443, 323538) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The six 2026 LOEs (323552, 323291, 323426, 323497, 323443, 323538) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323497

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 94 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA Health Advisory for lifetime exposure to Ammonia as a drinking water level is a concentration of 30 mg/L

Guideline Reference:

2012 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323552

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 1 of 57 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for AmmoniaNAFreshwater 2013 document.

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323291

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 57 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323443

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323426

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA Health Advisory for lifetime exposure to Ammonia as a drinking water level is a concentration of 30 mg/L

Guideline Reference:

2012 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161408, Ammonia	Region 1
Iron Gate Reservoir

LOE ID:

323538

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	166122	Region 1
Iron Gate Reservoir

Pollutant:	Chlordane
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 166122, Chlordane	Region 1
Iron Gate Reservoir

LOE ID:

44753

Pollutant:

Chlordane

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlordane, Total. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). Total chlordane was calculated as the sum of the following chlordane isomers: cis- and trans-chlordane, cis- and trans-nonachlor, and oxychlordane.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Region (NCRWQCB 2011): No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. There shall be no bioaccumulation of pesticide concentrations found in bottom sediments or aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for total chlordane in fish tissue is 3.9 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.

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166122, Chlordane	Region 1
Iron Gate Reservoir

LOE ID:

44754

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Chlordane concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166122, Chlordane	Region 1
Iron Gate Reservoir

LOE ID:

44755

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	157041	Region 1
Iron Gate Reservoir

Pollutant:	Chlorophyll-a
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. The four 2026 LOEs (324133, 324134, 324136, 324128) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The four 2026 LOEs (324133, 324134, 324136, 324128) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157041, Chlorophyll-a	Region 1
Iron Gate Reservoir

LOE ID:

324128

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 2 of 26 samples exceeded the water quality threshold for Chlorophyll a.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses. (Basin Plan, 2018)

Objective/Criterion Reference:

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

Evaluation Guideline:

North Carolina Administrative code (NCAC), Title 15ANAEnvironmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife).Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2019-03-16 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157041, Chlorophyll-a	Region 1
Iron Gate Reservoir

LOE ID:

324133

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 5 of 28 samples exceeded the water quality threshold for Chlorophyll a.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2019-03-16 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157041, Chlorophyll-a	Region 1
Iron Gate Reservoir

LOE ID:

324134

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2019-03-16 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157041, Chlorophyll-a	Region 1
Iron Gate Reservoir

LOE ID:

324136

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2019-03-16 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	166123	Region 1
Iron Gate Reservoir

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
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 166123, DDT (Dichlorodiphenyltrichloroethane)	Region 1
Iron Gate Reservoir

LOE ID:

33963

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Neither of the samples exceeded the 15ppb evaluation guideline for Total DDT which is the sum of all available 4,4'- and 2,4'- isomers of DDT, DDE, and DDD. Only DDE concentrations in fish tissue (wet weight) were reported and both values were <2 ppb.

Data Reference:

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (NCRWQCB 2011): No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. There shall be no bioaccumulation of pesticide concentrations found in bottom sediments or aquatic life. Waters designated for use as domestic or municipal supply shall not contain concentrations of pesticides in excess of the limiting concentrations set forth in California Code of Regulations, Title 22, Division 4, Chapter 15, Article 4, Section 64444, and listed in Table 3.2 of the Basin Plan.

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for total DDT in fish tissue is 15 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:

Black bullhead and largemouth bass composite tissue samples taken from reservoirs (Iron Gate Reservoir).

Temporal Representation:

Samples were taken in 2003.

Environmental Conditions:

QAPP Information:

PacifiCorp 2004 report Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs contains laboratory data in dry weight on page 27. The QA/QC information for these lab data is on page 28.

QAPP Information Reference(s):


DECISION ID	103602	Region 1
Iron Gate Reservoir

Pollutant:	Dieldrin
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line(s) of evidence are necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. None samples exceed the objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. None of the samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 103602, Dieldrin	Region 1
Iron Gate Reservoir

LOE ID:

44760

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Dieldrin. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Dieldrin concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 103602, Dieldrin	Region 1
Iron Gate Reservoir

LOE ID:

44759

Pollutant:

Dieldrin

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Dieldrin. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for dieldrin in fish tissue is 0.32 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.

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 103602, Dieldrin	Region 1
Iron Gate Reservoir

LOE ID:

44761

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	166124	Region 1
Iron Gate Reservoir

Pollutant:	Endrin
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 166124, Endrin	Region 1
Iron Gate Reservoir

LOE ID:

44765

Pollutant:

Endrin

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endrin. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for endrin in fish tissue is 660 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.

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

Guideline Reference:

Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166124, Endrin	Region 1
Iron Gate Reservoir

LOE ID:

44766

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Endrin concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166124, Endrin	Region 1
Iron Gate Reservoir

LOE ID:

44767

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	166125	Region 1
Iron Gate Reservoir

Pollutant:	Heptachlor
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 166125, Heptachlor	Region 1
Iron Gate Reservoir

LOE ID:

44772

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Heptachlor concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166125, Heptachlor	Region 1
Iron Gate Reservoir

LOE ID:

44771

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	166126	Region 1
Iron Gate Reservoir

Pollutant:	Heptachlor epoxide
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 166126, Heptachlor epoxide	Region 1
Iron Gate Reservoir

LOE ID:

44778

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor epoxide. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Heptachlor Epoxide concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166126, Heptachlor epoxide	Region 1
Iron Gate Reservoir

LOE ID:

44783

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166126, Heptachlor epoxide	Region 1
Iron Gate Reservoir

LOE ID:

44777

Pollutant:

Heptachlor epoxide

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Heptachlor epoxide. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for heptachlor epoxide in fish tissue is 0.93 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.

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

Guideline Reference:

Public Health Goal for Heptachlor and Heptachlor Epoxide in Drinking Water

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	166127	Region 1
Iron Gate Reservoir

Pollutant:	Hexachlorobenzene/ HCB
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 166127, Hexachlorobenzene/ HCB	Region 1
Iron Gate Reservoir

LOE ID:

44784

Pollutant:

Hexachlorobenzene/ HCB

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Hexachlorobenzene. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for hexachlorobenzene in fish tissue is 2.8 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.

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

Guideline Reference:

Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	166128	Region 1
Iron Gate Reservoir

Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
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 166128, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 1
Iron Gate Reservoir

LOE ID:

44769

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for HCH, gamma. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Lindane concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166128, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 1
Iron Gate Reservoir

LOE ID:

44768

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for lindane in fish tissue is 4.6 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.

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

Guideline Reference:

Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166128, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 1
Iron Gate Reservoir

LOE ID:

44770

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	161482	Region 1
Iron Gate Reservoir

Pollutant:	Microcystins
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. The 2026 LOEs (325442, 325457, 325464, 325475, 325479, 325481, 325509, 325512, 325521, 325523, 325526, 325531) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (325442, 325457, 325464, 325475, 325479, 325481, 325509, 325512, 325521, 325523, 325526, 325531) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325464

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Water Contact Recreation

Number of Samples:

122

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 39 of 122 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life, as specified in subsection 3.3.16 of the 2018 Water Quality Control Plan for the North Coast Region (Basin Plan).

Objective/Criterion Reference:

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

Evaluation Guideline:

The California Cyanobacteria and Harmful Algal Bloom (CCHAB) Network established 6 ug/L of microcystins as the water concentration protective of swimmers and other contact recreational users including water-skiing/jet-skiing, fishing, boating, sail boarding, and canoeing.

Guideline Reference:

Appendix to the CCHAB preliminary changes to the statewide voluntary guidance on cyanoHABs in recreational waters, January 2016. Appendix A. Description of cyanotoxin triggers in recreational waters.

Spatial Representation:

The samples were collected at 1 monitoring site: IGJW (Iron Gate Reservoir at Jay Williams Boat Ramp(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325531

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 14 of 54 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

California Office of Environmental Health Hazard Assessment (OEHHA) established 2 ug/L of microcystins as the subchronic water concentration for dog intake/ingestion (Office of Environmental Health Hazard Assessment Public Health Action Level for microcystin and Human Recreational Uses (May 2012)). OEHHA Action Level for subchronic water intake, dog.

Guideline Reference:

Toxicological Summary and Suggested Action Levels to Reduce Potential Adverse Health Effects of Six Cyanotoxins

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325442

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Water Contact Recreation

Number of Samples:

121

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 41 of 121 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Appendix to the CCHAB preliminary changes to the statewide voluntary guidance on cyanoHABs in recreational waters, January 2016. Appendix A. Description of cyanotoxin triggers in recreational waters.

Spatial Representation:

The samples were collected at 1 monitoring site: IGCC (Iron Gate Reservoir at Camp Creek(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325526

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Wildlife Habitat

Number of Samples:

122

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 51 of 122 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Toxicological Summary and Suggested Action Levels to Reduce Potential Adverse Health Effects of Six Cyanotoxins

Spatial Representation:

The samples were collected at 1 monitoring site: IGJW (Iron Gate Reservoir at Jay Williams Boat Ramp(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325521

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 25 of 54 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

USEPA 10-day microcystin health advisory for bottle-fed infants and young children of pre-school age is 0.3 ug/L.

Guideline Reference:

Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325481

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 15 of 54 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Toxicological Summary and Suggested Action Levels to Reduce Potential Adverse Health Effects of Six Cyanotoxins

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325509

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 10 of 54 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Appendix to the CCHAB preliminary changes to the statewide voluntary guidance on cyanoHABs in recreational waters, January 2016. Appendix A. Description of cyanotoxin triggers in recreational waters.

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325512

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Wildlife Habitat

Number of Samples:

121

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 51 of 121 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Toxicological Summary and Suggested Action Levels to Reduce Potential Adverse Health Effects of Six Cyanotoxins

Spatial Representation:

The samples were collected at 1 monitoring site: IGCC (Iron Gate Reservoir at Camp Creek(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325523

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

113

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 65 of 113 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

USEPA 10-day microcystin health advisory for bottle-fed infants and young children of pre-school age is 0.3 ug/L.

Guideline Reference:

Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins

Spatial Representation:

The samples were collected at 1 monitoring site: IGCC (Iron Gate Reservoir at Camp Creek(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325475

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 8 of 54 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Appendix to the CCHAB preliminary changes to the statewide voluntary guidance on cyanoHABs in recreational waters, January 2016. Appendix A. Description of cyanotoxin triggers in recreational waters.

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325479

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

114

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 59 of 114 samples exceeded the water quality threshold for Microcystins, Total.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

USEPA 10-day microcystin health advisory for bottle-fed infants and young children of pre-school age is 0.3 ug/L.

Guideline Reference:

Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins

Spatial Representation:

The samples were collected at 1 monitoring site: IGJW (Iron Gate Reservoir at Jay Williams Boat Ramp(Public Health)).

Temporal Representation:

The samples were collected between the dates of 2010-08-30 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 161482, Microcystins	Region 1
Iron Gate Reservoir

LOE ID:

325457

Pollutant:

Microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

USEPA 10-day microcystin health advisory for bottle-fed infants and young children of pre-school age is 0.3 ug/L.

Guideline Reference:

Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-10-12

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	166129	Region 1
Iron Gate Reservoir

Pollutant:	Mirex
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 166129, Mirex	Region 1
Iron Gate Reservoir

LOE ID:

44790

Pollutant:

Mirex

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Mirex. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for mirex in fish tissue is 0.28 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.

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

Guideline Reference:

Expedited Cancer Potency Values and Proposed Regulatory Levels for Certain Proposition 65 Carcinogens.

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	157042	Region 1
Iron Gate Reservoir

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
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. The 2026 LOEs (325732, 325829) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (325732, 325829) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157042, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 1
Iron Gate Reservoir

LOE ID:

325732

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for nitrate + nitrite (as N) that is incorporated by reference in the Water Quality Control Plan, North Coast Basin is 10.0 mg/L (Water Quality Control Plan, North Coast Basin).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157042, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 1
Iron Gate Reservoir

LOE ID:

325829

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	157043	Region 1
Iron Gate Reservoir

Pollutant:	Oxygen, Dissolved
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. The 2026 LOEs (326093, 326128, 326169, 326193, 326196, 326235) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (326093, 326128, 326169, 326193, 326196, 326235) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326196

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 66 of 87 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states: Dissolved oxygen concentrations shall conform to those limits listed in Section 3.3.5. Section 3.3.5 lists dissolved oxygen concentration limits for SPAWN beneficial use waters to be a daily minimum of 9.0 mg/L and a 7-day moving average of 11.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326235

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 44 of 87 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states: Dissolved oxygen concentrations shall conform to those limits listed in Section 3.3.5. Section 3.3.5 lists dissolved oxygen concentration limits for COLD beneficial use waters to be a daily minimum of 6.0 mg/L and a 7-day moving average of 8.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326128

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 44 of 89 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326093

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 89 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states: Dissolved oxygen concentrations shall conform to those limits listed in Section 3.3.5. Section 3.3.5 lists dissolved oxygen concentration limits for WARM beneficial use waters to be a daily minimum of 5.0 mg/L and a 7-day moving average of 6.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326193

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 40 of 87 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states: Dissolved oxygen concentrations shall conform to those limits listed in Section 3.3.5. Section 3.3.5 lists dissolved oxygen concentration limits for WARM beneficial use waters to be a daily minimum of 5.0 mg/L and a 7-day moving average of 6.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157043, Oxygen, Dissolved	Region 1
Iron Gate Reservoir

LOE ID:

326169

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 1 of 89 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states: Dissolved oxygen concentrations shall conform to those limits listed in Section 3.3.5. Section 3.3.5 lists dissolved oxygen concentration limits for COLD beneficial use waters to be a daily minimum of 6.0 mg/L and a 7-day moving average of 8.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	157044	Region 1
Iron Gate Reservoir

Pollutant:	Selenium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
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 The 2026 LOE (322743) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOE (322743) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157044, Selenium	Region 1
Iron Gate Reservoir

LOE ID:

44803

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Selenium. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Region (NCRWQCB 2011): 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.

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.

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 157044, Selenium	Region 1
Iron Gate Reservoir

LOE ID:

322743

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 Iron Gate Reservoir to determine beneficial use support and the results are as follows: 0 of 7 samples exceeded the water quality threshold for Selenium. Monitors collected 9 composites: 1 composite of Black Crappie composed of 10 fish, 2 composites of Brown Bullhead composed of 5 fish each, 1 composite of Hitch composed of 10 fish, 1 composite of Largemouth Bass composed of 5 fish, 1 composite of Largemouth Bass composed of 10 fish, 2 composites of Redear Sunfish composed of 5 fish each, and 1 composite of Redear Sunfish composed of 10 fish. Because 2 or more composites were collected within the same averaging period, these composites resulted in 7 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:

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): 105PIG154 (Iron Gate Reservoir).

Temporal Representation:

Environmental Conditions:

QAPP Information:

QAPP for Surface Water Ambient Monitoring Program (SWAMP)

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	163020	Region 1
Iron Gate Reservoir

Pollutant:	Specific Conductivity
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 The 2026 LOEs (318154, 318205) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (318154, 318205) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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 163020, Specific Conductivity	Region 1
Iron Gate Reservoir

LOE ID:

318205

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed the specific conductivity data for parent project Klamath Hydroelectric Settlement Monitoring and determined that 0 samples exceed the water quality objective for years 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2019, 2020, or 2021, so that 0 of 10 samples exceed the water quality objective.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (NCRWQCB 2007): The 90% upper limit specific conductance objective at 77 F is 425 micromhos (or mS/cm2). The 50% upper limit specific conductance objective at 77 F is 275 micromhos (or mS/cm2). The 90% and 50% upper limits represent the 90/50 percentile values for a calendar year. 90% or 50% or more of the values must be less than or equal to the upper limit.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

These samples were collected at sampling station name: Klamath River below Copco Dam (RM 196.45; Baseline); station code: KR19645_KHSA.

Temporal Representation:

These samples were collected from 9/15/2010-12/14/2021.

Environmental Conditions:

QAPP Information:

QAPP for Klamath Hydroelectric Settlement Monitoring

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 163020, Specific Conductivity	Region 1
Iron Gate Reservoir

LOE ID:

318154

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed specific conductivity data for parent project Klamath Hydroelectric Settlement Monitoring and determined that calendar years 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2019, 2020, and 2021 did not exceed either the 90% or 50% upper limit, so that 0 of 10 samples exceed the water quality objective.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (NCRWQCB 2007): The 90% upper limit specific conductance objective at 77 F is 285 micromhos (or mS/cm2). The 50% upper limit specific conductance objective at 77 F is 250 micromhos (or mS/cm2). The 90% and 50% upper limits represent the 90/50 percentile values for a calendar year. 90% or 50% or more of the values must be less than or equal to the upper limit.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

These samples were collected at sampling station name: Iron Gate Reservoir (RM 190.19; Baseline); station code: KR19019-KHSA.

Temporal Representation:

These samples were collected from 9/15/2010-12/17/2021.

Environmental Conditions:

QAPP Information:

QAPP for Klamath Hydroelectric Settlement Monitoring

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	157045	Region 1
Iron Gate Reservoir

Pollutant:	Temperature, water
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. The 2026 LOEs (326925, 326933) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (326925, 326933) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157045, Temperature, water	Region 1
Iron Gate Reservoir

LOE ID:

326925

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 27 of 87 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Water Board that such alteration in temperature does not adversely affect beneficial uses. At no time or place shall the temperature of any COLD water be increased more than 5 degrees Fahrenheit (F) above natural receiving water temperature (Basin Plan, North Coast Region).

Objective/Criterion Reference:

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

Evaluation Guideline:

According to Carter (2008) the lethal temperature evaluation guideline for salmonid spawning, egg incubation & fry emergence is 20C.

Guideline Reference:

Effects of Temperature, Dissolved Oxygen/Total Dissolved Gas, Ammonia, and pH on Salmonids. Implications for California's North Coast TMDLs. California Regional Water Quality Control Board, North Coast Region

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157045, Temperature, water	Region 1
Iron Gate Reservoir

LOE ID:

326933

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 17 of 89 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

According to Carter (2008) the lethal temperature evaluation guideline for salmonid spawning, egg incubation & fry emergence is 20C.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2010-09-15 and 2021-12-14

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	166130	Region 1
Iron Gate Reservoir

Pollutant:	Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)
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 166130, Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)	Region 1
Iron Gate Reservoir

LOE ID:

44756

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDT, Total. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). Total DDT was calculated as the sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166130, Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)	Region 1
Iron Gate Reservoir

LOE ID:

44758

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 DDT concentration of 1000 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 166130, Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)	Region 1
Iron Gate Reservoir

LOE ID:

44757

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	157046	Region 1
Iron Gate Reservoir

Pollutant:	Turbidity
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. The 2026 LOEs (327206, 327238) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (327206, 327238) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 157046, Turbidity	Region 1
Iron Gate Reservoir

LOE ID:

327206

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 6 of 11 samples exceeded the water quality threshold for Turbidity.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Chapter 15, Division 4, Article 4, Section 64435 (Tables 2 and 3), and Section 64444.5 (Table 5), and listed in Table 3-2 of this Plan (Water Quality Control Plan, North Coast Basin).

Objective/Criterion Reference:

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

Evaluation Guideline:

California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's 'Chemical Constituents' objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment.

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: KR19645_KHSA (Klamath River below Copco Dam (RM 196.45; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2015-02-17 and 2015-12-08

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 157046, Turbidity	Region 1
Iron Gate Reservoir

LOE ID:

327238

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Klamath Hydroelectric Settlement Monitoring data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 4 of 13 samples exceeded the water quality threshold for Turbidity.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: KR19019_KHSA (Iron Gate Reservoir (RM 190.19; Baseline)).

Temporal Representation:

The samples were collected between the dates of 2014-07-09 and 2016-08-10

Environmental Conditions:

QAPP Information:

Klamath Hydroelectric Settlement Monitoring QAPP

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	78049	Region 1
Iron Gate Reservoir

Pollutant:	Zinc
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
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 minimum of one line of evidence is necessary to assess listing status. One line of evidence is 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 placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of nine samples exceed the evaluation guideline used to interpret the narrative toxicity objective, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 78049, Zinc	Region 1
Iron Gate Reservoir

LOE ID:

31951

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the sediment guideline. The data was assumed to be reported as dry weight. Sample values ranged from 66 mg/kg to 89 mg/kg.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (NCRWQCB 2011): 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Water Board.

Objective/Criterion Reference:

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

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for zinc is 459 mg/kg dry weight (MacDonald et al 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Composite subsurface sediment samples were analyzed from the top 7 feet from nine separate boring sites in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	104063	Region 1
Iron Gate Reservoir

Pollutant:	alpha-Endosulfan (Endosulfan 1)
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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line(s) of evidence are necessary to assess listing status. Three line(s) of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. None samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 104063, alpha-Endosulfan (Endosulfan 1)	Region 1
Iron Gate Reservoir

LOE ID:

44764

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endosulfan I. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009).

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 Endosulfan concentration of 100 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 104063, alpha-Endosulfan (Endosulfan 1)	Region 1
Iron Gate Reservoir

LOE ID:

44763

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 104063, alpha-Endosulfan (Endosulfan 1)	Region 1
Iron Gate Reservoir

LOE ID:

44762

Pollutant:

alpha-Endosulfan (Endosulfan 1)

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The modified OEHHA Fish Contaminant Goal for endosulfan (l and ll) in fish tissue is 13,000 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.

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

Guideline Reference:

Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis

Spatial Representation:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	155024	Region 1
Iron Gate Reservoir

Pollutant:	pH
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. The 2026 LOEs (318153, 318204) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

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:	The 2026 LOEs (318153, 318204) will not be assessed for the 2026 Integrated Report. Section 6.1.1 of the Listing Policy states that "Regional Water Boards shall review all readily available data and information." The data solicitation period for the 2026 Integrated Report closed on October 21, 2022. The JC Boyle dam (in Oregon), Iron Gate dam, Copco 1 dam, and Copco dam were removed from the Klamath River in 2024. Section 6.1.5.3 of the Listing Policy states that "If the implementation of a management practice(s) has resulted in a change in the water body segment, only recently collected data [since the implementation of the management measure(s)] should be considered." Because dam removal has significantly changed the Klamath River hydrology, data for Iron Gate reservoir, Copco 1 reservoir, Copco 2 reservoir, and the mainstem Klamath River will not be assessed for the 2026 Integrated Report. Data collected and submitted after the drawn-downs and dam removals will be assessed in future Integrated Reports.

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 155024, pH	Region 1
Iron Gate Reservoir

LOE ID:

318153

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

216

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed the pH data and determined that 32 samples were less then pH 7.0 and 32 samples were greater than pH 8.5, so that 64 of 216 samples exceed the water quality objective.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, North Coast Basin, Chapter III, General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The pH shall conform to the values listed in Table 3-1 which states that the water quality objective for pH shall not be depressed below 6.5 or raised above 8.5.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

These samples were collected at sampling station name: Iron Gate Reservoir (RM 190.19; Baseline); station code: KR19019-KHSA.

Temporal Representation:

These samples were collected from 9/15/2010-12/17/2021.

Environmental Conditions:

QAPP Information:

QAPP for Klamath Hydroelectric Settlement Monitoring

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674

Line of Evidence (LOE) for Decision ID 155024, pH	Region 1
Iron Gate Reservoir

LOE ID:

318204

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed the pH data and determined that 1 sample was less than pH 7.0 and 15 samples were greater than pH 8.5, so that 16 of 86 samples exceed the water quality objective.

Data Reference:

Field, WQ from the Klamath Basin Monitoring Program for the 2026 Integrated Report in Region 1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

These samples were collected at sampling station name: Klamath River below Copco Dam (RM 196.45; Baseline); station code: KR19645_KHSA.

Temporal Representation:

These samples were collected from 9/15/2010-12/14/2021.

Environmental Conditions:

QAPP Information:

QAPP for Klamath Hydroelectric Settlement Monitoring

QAPP Information Reference(s):

San Francisco Estuary Institute - QA doc_cyano SOP (2009) - Klamath Hydroelectric Settlement Monitoring - 402674


DECISION ID	74837	Region 1
Iron Gate Reservoir

Pollutant:	Cyanobacteria hepatotoxic microcystins
Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status	Original
Sources:	Agriculture \| Drainage/Filling Of Wetlands \| Grazing-Related Sources \| Irrigated Crop Production \| Logging Road Construction/Maintenance \| Road Construction \| Silviculture
TMDL Name:	Klamath River Nutrients, Temperature, DO, and Microcystin.
TMDL Project Code:	97
Date TMDL Approved by USEPA:	12/28/2010
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional Board Conclusion: This pollutant was placed on the section 303(d) List in a previous Integrated Report cycle. No new information was reviewed for the current Integrated Report cycle. Therefore, the previous conclusion remains unchanged; however, a TMDL has been developed and approved by the USEPA and the approved implementation plan is expected to result in full attainment of the standard within a specified time frame. The previous conclusion is as follows: This pollutant was added to the Section 303(d) List on May 29, 2008, by the US EPA as part of the 2006 303(d) List Update process, which applies to the mainstem Klamath River in the Klamath River Hydrologic Unit, Middle Klamath River Hydrologic Area, Oregon to Iron Gate reach, excluding the riverine reach from the Oregon border downstream to the beginning of Copco 1 Reservoir (i.e., the mainstem Klamath River from the beginning of Copco 1 Reservoir to Iron Gate Dam). This listing applies to the Iron Gate Reservoir. This pollutant is being considered for removal from the Section 303(d) List under Section 4.11 of the Listing Policy. Two lines of evidence are available in the administrative record. The LOE for microcystin toxin in the water column (LOE 26006) has an evaluation guideline (WHO 2003) that meets the requirements of the Listing Policy. The LOE for microcystin toxin in tissue (LOE 25755) has an evaluation guideline (Alexeff 2008) that State Water Board staff believes does not meet the requirements of the Listing Policy, due to the fact that the guideline has not been peer-reviewed or published in an official OEHHA agency document. Therefore, only data from LOE 26006 for microcystin in the water column were utilized to assess this pollutant. Data from LOE 25755 on microcystin in tissue are as follows, but were not utilized to assess this pollutant: Eight out of 25 tissue microcystin toxin samples exceeded the evaluation guideline (Alexeff 2008). Based on the readily available data and information, the situation-specific weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the Section 303(d) List in the Water Quality Limited Segments category (i.e., sufficient justification to not delist). This conclusion is based on the staff findings that: (1) On May 29, 2008, the US EPA identified the portion of the "Klamath River Hydrologic Unit (HU), Middle HA Hydrologic Area (HA), from Oregon to Iron Gate [reservoir]" that is impaired due to microcystin toxins as the area including the Copco 1 and 2 reservoirs, Iron Gate Reservoirs, and waters in between. (2) Seven out of 14 water column microcystin toxin samples exceed the evaluation guideline used to interpret the water quality objective. (3) Any exceedance of the evaluation guidelines indicates non-attainment of standards. In compliance with Section 4.11 of the Listing Policy, a water segment shall not be removed from the Section 303(d) List if the weight of evidence indicates non-attainment. (4) The data used satisfies the data quality requirements of Section 6.1.4 of the Policy. (5) The data used satisfies the data quantity requirements of Section 6.1.5 of the Policy. (6) Pursuant to Section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 74837, Cyanobacteria hepatotoxic microcystins	Region 1
Iron Gate Reservoir

LOE ID:

26006

Pollutant:

Cyanobacteria hepatotoxic microcystins

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Seven of the 14 microcystin samples collected in Iron Gate Reservoir exceed the evaluation guideline. Additionally, ten of the 14 microcystin samples exceeded the Blue Green Algae Work Group (2008) guideline for microcystin toxin of 8 ug/L to protect the recreational exposure of a child. Microcystin concentrations range from non-detect to 1,600 ug/L. Samples were collected and summarized by the Karuk Tribe of California (Karuk 2008 - data).

Data Reference:

Karuk Tribe 2008 BGA Data (KR TOX Table 2008). Data for Blue Green Algae in the Klamath River, July 2008 to September 2008

Cyanobacteria in California Recreational Water Bodies. Providing Voluntary Guidance about Harmful Algal Blooms, Their Monitoring, and Public Notification. Draft. September 2008. Blue Green Algae Work Group of the State Water Resources Control Board, Department of Public Health, and Office of Environmental Health and Hazard Assessment

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (NCRWQCB 2007, p. 3-4.00): All water 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Water Board.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - North Coast Region (Region 1)

Evaluation Guideline:

Per the World Health Organization (WHO 2003): The recommended guideline for microcystin toxin in recreational waters associated with a moderate probability of adverse health effects is 20 ug/L.

Guideline Reference:

World Health Organization. 2003. Guidelines for Safe Recreational Water Environments: Volume 1 Coastal and Freshwaters.

Spatial Representation:

Samples were collected from 6 locations in Iron Gate Reservoir as follows: (1) in the open water near the dam, (2) at the Camp Creek Recreation Area, (3) at the Jay Williams Boat Dock, (4) at the Narrows, (5) in the open water scum, and (6) at the Spring Hill Boat Ramp.

Temporal Representation:

Grab samples were collected in Iron Gate Reservoir on 14 occasions between July 8, 2008 and September 2, 2008.

Environmental Conditions:

There are no known environmental conditions (e.g., seasonality, land use practices, fire events, storms, etc.) that are related to these data.

QAPP Information:

Samples were collected according to the procedures summarized in the "Draft Klamath River Nutrient, Periphyton, Phytoplankton and Algal Toxin Sampling Analysis Plan" (Karuk 2008-MonitoringPlan).

QAPP Information Reference(s):

Draft Mid-Klamath River Nutrient, Periphyton, Phytoplankton and Algal Toxin Sampling Analysis Plan (SAP). Karuk Tribe of California Water Quality Program.

Line of Evidence (LOE) for Decision ID 74837, Cyanobacteria hepatotoxic microcystins	Region 1
Iron Gate Reservoir

LOE ID:

25755

Pollutant:

Cyanobacteria hepatotoxic microcystins

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish whole body

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Eight out of 25 microcystin samples collected from fish tissue from Iron Gate Reservoir and Iron Gate Hatchery exceed the evaluation guideline. Sample concentrations range from 0.00 to 229.37 ng/g. Tissue samples were collected from 22 yellow perch fillet samples from Iron Gate Reservoir and from 3 yearling fall Chinook liver, stomach, and fillet samples from Iron Gate Hatchery. It is appropriate to include the Iron Gate Hatchery samples as the Chinook raised at the Hatchery were raised in water directly from Iron Gate Reservoir. Fish samples were collected by the California Department of Fish and Game (CDFG) and analyzed for microcystin by the CDFG Fish and Wildlife Water Pollution Control Laboratory in Rancho Cordova, CA. Data are summarized by Kann (2008). The presence of the toxin microcystin in fish and mussels in the Klamath River has the potential to impair the Native American Culture (CUL) and Subsistence Fishing (FISH) beneficial uses, as well as the Commercial and Sport Fishing (COMM) beneficial use listed above.

Data Reference:

Technical Memorandum. Microcystin Bioaccumulation in Klamath River Fish and Freshwater Mussel Tissue: Preliminary 2007 Results. Prepared by Jacob Kann, Ph.D. of Aquatic Ecosystem Sciences LLC. Prepared for Karuk Tribe of California.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Per the Basin Plan (North Coast RWQCB 2007): 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Water Board.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - North Coast Region (Region 1)

Evaluation Guideline:

Per the California Office of Environmental Health Hazard Assessment (OEHHA) (Alexeeff 2008): The upper bound of the Advisory Tissue Level range for the one serving (8 oz. uncooked fish, 6 oz. cooked, equal to 32 g/day) per week category is 26 ng total microcystins per gram of fish (26 ng/g). This Advisory Tissue Level applies to a composite of 3 or more individual samples of edible tissue.

Guideline Reference:

Letter of August 6, 2008, to Randy Landolt, Managing Director, Pacificorp Energy, from George V. Alexeeff, Ph.D, DABT, Deputy Director for Scientific Affairs, California Office of Environmental Health Hazard Assessment, regarding information related to the occurrence of microcystin in the tissues of Klamath River biota

Spatial Representation:

Yellow perch samples were collected from Iron Gate Reservoir. Chinook tissue samples were collected from Iron Gate Hatchery.

Temporal Representation:

Samples from Iron Gate Reservoir were collected September 6 to 7, 2007. Samples from the Hatchery were collected on July 13, 2007.

Environmental Conditions:

There are no known environmental conditions (e.g., seasonality, land use practices, fire events, storms, etc.) that are related to these data.

QAPP Information:

Samples were collected and analyzed in accordance with the quality assurance procedures described in the "Technical Memorandum. Microcystin Bioaccumulation in Klamath River Fish and Freshwater Mussel Tissue: Preliminary 2007 Results" (Kann 2008).

QAPP Information Reference(s):


DECISION ID	78095	Region 1
Iron Gate Reservoir

Pollutant:	Arsenic
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Carry over no new data Regional Board Conclusion: The pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: 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. One line of evidence is available to assess protection of the commercial and sport fishing (COMM) beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) The data in LOE 31885 evaluating the COMM beneficial use were all detect not quantifiable (DNQ) and the data reporting limit and method detection limit were above the evaluation guideline. Thus, per the Listing Policy the data were not used in this assessment. Therefore, there are no data available to assess against protection of the MUN beneficial use. (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 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.

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.

Line of Evidence (LOE) for Decision ID 78095, Arsenic	Region 1
Iron Gate Reservoir

LOE ID:

31884

Pollutant:

Arsenic

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Two detect not quantified (DNQ) sample results were not used in the assessment because the laboratory data reporting limit was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA screening value is 3.4 ppb (wet weight). 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. (EPA 823-B-00-007).

Guideline Reference:

Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis

Spatial Representation:

Black bullhead and largemouth bass composite tissue samples taken from reservoirs (Iron Gate Reservoir).

Temporal Representation:

Samples were taken in June 4, 2003.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):


DECISION ID	78458	Region 1
Iron Gate Reservoir

Pollutant:	Chromium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional board conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged and is as follows: 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 minimum of one line of evidence is necessary to assess listing status. One line of evidence is 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 placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of nine samples exceed the evaluation guideline used to interpret the narrative toxicity objective, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 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.

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.

Line of Evidence (LOE) for Decision ID 78458, Chromium	Region 1
Iron Gate Reservoir

LOE ID:

31949

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

None of the twelve samples exceeded the sediment guideline. The data was assumed to be reported as dry weight. Sample values ranged from 25 mg/kg to 39 mg/kg.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Water Board.

Objective/Criterion Reference:

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

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for chromium is 111 mg/kg dry weight (MacDonald et al 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Composite subsurface sediment samples were analyzed from the top 7 feet from nine separate boring sites in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	78459	Region 1
Iron Gate Reservoir

Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
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 minimum of one line of evidence is necessary to assess listing status. One line of evidence is 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 placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of nine samples exceed the evaluation guideline used to interpret the narrative toxicity objective, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 78459, Copper	Region 1
Iron Gate Reservoir

LOE ID:

31948

Pollutant:

Copper

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the sediment guideline. The data was assumed to be reported as dry weight. Sample values ranged from 35.2 mg/kg to 51.3 mg/kg.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for copper is 149 mg/kg dry weight (MacDonald et al 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Composite subsurface sediment samples were analyzed from the top 7 feet from nine separate boring sites in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	78942	Region 1
Iron Gate Reservoir

Pollutant:	Dioxin Toxic Equivalents
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
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. One line of evidence is available to assess protection of the municipal and domestic supply (MUN) beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of one sediment sample exceeds the evaluation guideline used to assess the MUN beneficial use, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 78942, Dioxin Toxic Equivalents	Region 1
Iron Gate Reservoir

LOE ID:

31891

Pollutant:

Dioxin Toxic Equivalents

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

The sample did not exceed the evaluation guideline. The data were assumed to be reported as dry weight. A toxic equivalency quotient (TEQ) for the dioxin data was calculated based upon World Health Organization toxic equivalency factors (TEFs) for 1) mammal/human (2006), 2) fish (1998), and 3) birds (1998). TEQs were 2.27, 1.68, and 1.96 ppt respectively. All TEQs were within the range considered as background.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Dioxin concentrations in the range of 2-5 ppt (dry weight) TEQ appear to represent a reasonable estimate of what could be expected as background in non-source-impacted sediments anywhere in the country, specifically including the west (USEPA 2000).

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. Region 10 Office of Water, Seattle, WA

Spatial Representation:

A composite subsurface sediment sample was analyzed from the top 5 feet from station IG7-S1 in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	78460	Region 1
Iron Gate Reservoir

Pollutant:	Lead
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
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 minimum of one line of evidence is necessary to assess listing status. One line of evidence is 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 placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of eight samples exceed the evaluation guideline used to interpret the narrative toxicity objective, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 78460, Lead	Region 1
Iron Gate Reservoir

LOE ID:

31950

Pollutant:

Lead

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

None of the eight samples exceeded the sediment guideline. The data was assumed to be reported as dry weight. Sample values ranged from 5 mg/kg to 10 mg/kg.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity for sediment-dwelling organisms) for lead is 128 mg/kg dry weight (MacDonald et al 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Composite subsurface sediment samples were analyzed from the top 7 feet from nine separate boring sites in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	78508	Region 1
Iron Gate Reservoir

Pollutant:	Nickel
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
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 minimum of one line of evidence is necessary to assess listing status. One line of evidence is 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 placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of nine samples exceed the evaluation guideline used to interpret the narrative toxicity objective, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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.

Line of Evidence (LOE) for Decision ID 78508, Nickel	Region 1
Iron Gate Reservoir

LOE ID:

31952

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Non-fixed station physical/chemical (conventional + toxicants)

Data Used to Assess Water Quality:

None of the twelve samples exceeded the sediment guideline. The data was assumed to be reported as dry weight.

Data Reference:

Preliminary Review of 2006 Analytical Testing Data From Sediment Sampling Conducted at Iron Gate, Copco 1, and JC Boyle Reservoirs Klamath River, Oregon and California

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for nickel is 48.6 mg/Kg dry weight.

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Composite subsurface sediment samples were analyzed from the top 7 feet from nine separate boring sites in Iron Gate Reservoir.

Temporal Representation:

Sediment samples were taken between June 23 and July 12, 2006.

Environmental Conditions:

QAPP Information:

Data were submitted without a Quality Assurance Project Plan and are not part of a major monitoring program considered to be of good quality. The quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	79354	Region 1
Iron Gate Reservoir

Pollutant:	PCBs (Polychlorinated biphenyls)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Carry over no new data Regional Board Conclusion: The pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: 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. One line of evidence is available to assess protection of the cold freshwater habitat (COLD) beneficial use, one line of evidence is available to assess protection of the warm freshwater habitat (WARM) beneficial use, and two lines of evidence are available to assess protection of the commercial and sport fishing (COMM) beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category (i.e., sufficient justification to not 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) Zero of one fish tissue sample exceeds the evaluation guideline used to assess both the COLD and WARM beneficial uses. One of two fish tissue samples exceed the COMM evaluation guideline. These sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met, as a minimum of either (A) 16 samples, or (B) greater than or equal 2 exceedances of the objective with less than 16 samples is needed for application of Table 3.1. (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 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.

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.

Line of Evidence (LOE) for Decision ID 79354, PCBs (Polychlorinated biphenyls)	Region 1
Iron Gate Reservoir

LOE ID:

44802

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fish tissue analysis

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP data for Iron Gate Reservoir to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for PCB, Total. One composite (5 fish per composite) was generated from one species: largemouth bass. Details of the compositing protocol can be found in the March 2009 report entitled: "Contaminants in Fish from California Lakes and Reservoirs: Technical Report on Year One of a Two-Year Screening Study" (SWAMP, 2009). Total PCB was assessed for as follows: PCB aroclors and congeners were summed separately and the sum that yielded the highest value was used for the assessment.

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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 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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 79354, PCBs (Polychlorinated biphenyls)	Region 1
Iron Gate Reservoir

LOE ID:

44797

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments

Line of Evidence (LOE) for Decision ID 79354, PCBs (Polychlorinated biphenyls)	Region 1
Iron Gate Reservoir

LOE ID:

31914

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:

Fish tissue analysis

Data Used to Assess Water Quality:

One of one sample exceeded the evaluation guideline. Two composite samples were collected from one site in Iron Gate Reservoir on the same day, and thus, the average of the two composite samples was calculated, per USEPA 2001, resulting in a sample value of 5.74 ppb.

Data Reference:

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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:

Largemouth bass composite tissue samples taken from reservoirs (Iron Gate Reservoir).

Temporal Representation:

Samples were taken June 4, 2003.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Screening Level Determination of Chemical Contaminants in Fish Tissue in Selected Project Reservoirs. Final Technical Report

Line of Evidence (LOE) for Decision ID 79354, PCBs (Polychlorinated biphenyls)	Region 1
Iron Gate Reservoir

LOE ID:

44796

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:

Fish tissue analysis

Data Used to Assess Water Quality:

Data Reference:

Statewide Lakes Sportfish Contamination Study 2007 2008

Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey

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:

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:

Temporal Representation:

Data was collected on a single day 5/12/2008.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments