# Draft 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Cache Creek, North Fork (below Indian Valley Reservoir, Lake County)
Water Body ID: | CAR5134004020080731215753
Water Body Type: | River & Stream

DECISION ID | 12834
Pollutant: | Mercury
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Resource Extraction
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. 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. Thirty-one of 63 samples exceed the Cache Creek watershed-specific water quality objectives for trophic level 3 and 4 fish described in the Sacramento River and San Joaquin River Basin Plan. This exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 12834

LOE ID: | 22577
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 41
Number of Exceedances: | 23
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Asses Water Quality: | Fish were sampled for tissue analysis at one location from this reach. A total of 18 out of 30 samples exceeded the water quality objective for trophic level 3 fish. Twenty of the 30 samples from trophic level 3 fish were analyzed as whole fish samples, which were translated to a filet concentration by multiplying the whole body concentration by 1.62 (Peterson et al, 2007). For trophic level 3 fish, tissue was analyzed from: California Roach- 5 composite samples, 0.10-0.15 ppm (average 0.13 ppm), 4 exceedances; Sacramento Sucker- 18 samples, 0.06-0.47 ppm (average 0.17 ppm), 9 exceedances; and Speckled Dace- 7 composite samples, 0.09-0.24 ppm (average 0.14 ppm), 5 exceedances. A total of 5 out of 11 samples exceeded the water quality objective for trophic level 4 fish. For trophic level 4 fish, tissue was analyzed from: Sacramento Pikeminnow- 10 samples, 0.11-0.26 ppm (average 0.18 ppm), 4 exceedances; and Smallmouth Bass- 1 sample, 0.34 ppm, 1 exceedance.
Data Reference: | Mercury Bioaccumulation and Trophic Transfer in the Cache Creek Watershed, California, in Relation to Diverse Aqueous Mercury Exposure Conditions. CALFED Mercury Program Final Project Report. January 25, 2004
Water Quality Objective/Criterion: | Basin Plan water quality objectives for methylmercury in fish: for trophic level 3 fish, 0.12 mg methylmercury/kg wet weight of muscle; for trophic level 4 fish, 0.23 mg methylmercury/ kg wet weight of muscle tissue.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one location from the North Fork of Cache Creek directly downstream of the confluence with Benmore Canyon.
Temporal Representation: | Fish samples were collected during seven sampling events from 2/25/2000 to 5/15/2001.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Quality Control for all of the elements described in section 6.1.4 of the Policy was conducted in accordance with the CALFED Mercury Project QAPP (Puckett and van Buuren, 2000).
QAPP Information Reference(s):
LOE ID: | 22565
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 22
Number of Exceedances: | 8
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Asses Water Quality: | Fish were sampled by the California Department of Fish and Game for tissue analysis at one location from this reach. A total of 8 out of 14 samples exceeded the water quality objective for trophic level 3 fish. For trophic level 3 fish, tissue was analyzed from: Rainbow Trout- 6 samples, 0.10-0.16 ppm (average 0.12 ppm), 3 exceedances; and Sacramento Sucker- 8 samples, 0.07-0.51 ppm (average 0.18 ppm), 5 exceedances. A total of 0 out of 8 samples exceeded the water quality objective for trophic level 4 fish. For trophic level 4 fish, tissue was analyzed from Sacramento Pikeminnow. The mercury concentrations were 0.09-0.22 ppm with an average of 0.12 ppm.
Data Reference: | CVRWQCB. 2004. TMDL Fish Tissue Sampling- Cache Creek and Sacramento River Watersheds. Central Valley Regional Water Quality Control Board; and California Department of Fish and Game. Unpublished Data. August 2004.
Water Quality Objective/Criterion: | Basin Plan methylmercury water quality objectives: for trophic level 3 fish, 0.12 mg methylmercury/ kg wet weight of muscle; for trophic level 4 fish, 0.23 mg methylmercury/ kg wet weight of muscle tissue.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one location from the North Fork of Cache Creek directly downstream of the confluence with Benmore Canyon.
Temporal Representation: | Fish samples were collected during one sampling event on 9/30/2003.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent... Quality Control for all of the elements described in section 6.1.4 of the Policy was conducted in accordance with the CALFED Mercury Project QAPP (Puckett and van Buuren, 2000).
QAPP Information Reference(s):