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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Bishop Canal
Water Body ID: CAR6032028020171227020668
Water Body Type: River & Stream
 
DECISION ID
168709
Region 6     
Bishop Canal
 
Pollutant: Indicator Bacteria
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: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. 20 of 254 E. coli samples exceed the water quality objective. (Fecal coliform lines of evidence used in previous indicator bacteria decisions in the Lahontan Region have been removed decisions, starting in the 2026 Integrated Report, since the Lahontan Region's fecal coliform water quality objective was removed from the Basin Plan in 2024).

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. 20 of 254 E. coli samples, exceed the water quality objective.
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:
 
 
Line of Evidence (LOE) for Decision ID 168709, Indicator Bacteria
Region 6     
Bishop Canal
 
LOE ID: 336717
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 55
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Eastern Sierra Fecal Indicator Bacteria Study data for Bishop Canal to determine beneficial use support and the results are as follows: 6 of the 55 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ from the MBC Fecal indicator study in the Eastern Sierra for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in waters other than Lake Thaoe, where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): BC 23 (Bishop Creek Station 23).
Temporal Representation: The samples were collected between the days of 2015-06-03 and 2022-09-27 .
Environmental Conditions:
QAPP Information: MBC FIB Bacteria QAPP
QAPP Information Reference(s): MBC Aquatic Sciences - FIB Bacteria QAPP - Eastern Sierra Fecal Indicator Bacteria Study - 402598
QAPP Information Reference(s): MBC Aquatic Sciences - QAPP FIB Study V3. - Eastern Sierra Fecal Indicator Bacteria Study - 402641
 
Line of Evidence (LOE) for Decision ID 168709, Indicator Bacteria
Region 6     
Bishop Canal
 
LOE ID: 99784
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Bishop Canal to determine beneficial use support and the results are as follows: 0 of the 15 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): BIS.53
Temporal Representation: The samples were collected between the days of 2014-05-14 and 2015-10-13 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 168709, Indicator Bacteria
Region 6     
Bishop Canal
 
LOE ID: 336658
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 184
Number of Exceedances: 14
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Eastern Sierra Fecal Indicator Bacteria Study data for Bishop Canal to determine beneficial use support and the results are as follows: 14 of the 184 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.
Data Reference: WQ from the MBC Fecal indicator study in the Eastern Sierra for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use for waters other than Lake Tahoe, where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (ISWEBE 2018).
Objective/Criterion 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): BC 23 (Bishop Creek Station 23).
Temporal Representation: The samples were collected between the days of 2015-06-03 and 2022-09-27 .
Environmental Conditions:
QAPP Information: MBC FIB Bacteria QAPP
QAPP Information Reference(s): MBC Aquatic Sciences - FIB Bacteria QAPP - Eastern Sierra Fecal Indicator Bacteria Study - 402598
QAPP Information Reference(s): MBC Aquatic Sciences - QAPP FIB Study V3. - Eastern Sierra Fecal Indicator Bacteria Study - 402641