Final California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	Ash Creek (Siskiyou County)
Water Body ID:	CAR5052403020180615027802
Water Body Type:	River & Stream


DECISION ID	127090	Region 5
Ash Creek (Siskiyou County)

Pollutant:	Indicator Bacteria
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 127090, Indicator Bacteria	Region 5
Ash Creek (Siskiyou County)

LOE ID:

194727

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Ash Creek (Siskiyou County) to determine beneficial use support and the results are as follows: 1 of the 5 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:

Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-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): B5-UCD-Tate

Temporal Representation:

The samples were collected between the days of 2011-06-01 and 2011-10-18 .

Environmental Conditions:

QAPP Information:

Kenneth W. Tate, Ph.D., CRM. 2011. UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)., Kenneth W. Tate, Ph.D., CRM. 2016. UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP)

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 127090, Indicator Bacteria	Region 5
Ash Creek (Siskiyou County)

LOE ID:

194842

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Ash Creek (Siskiyou County) to determine beneficial use support and the results are as follows: 0 of the 5 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:

Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): B6-UCD-Tate

Temporal Representation:

The samples were collected between the days of 2011-06-01 and 2011-10-18 .

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP)

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 127090, Indicator Bacteria	Region 5
Ash Creek (Siskiyou County)

LOE ID:

194783

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Ash Creek (Siskiyou County) to determine beneficial use support and the results are as follows: 0 of the 4 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:

Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): B8-UCD-Tate

Temporal Representation:

The samples were collected between the days of 2011-07-26 and 2011-10-18 .

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP)

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 127090, Indicator Bacteria	Region 5
Ash Creek (Siskiyou County)

LOE ID:

194891

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): B7-UCD-Tate

Temporal Representation:

The samples were collected between the days of 2011-06-01 and 2011-10-18 .

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP)

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 127090, Indicator Bacteria	Region 5
Ash Creek (Siskiyou County)

LOE ID:

194813

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): B9-UCD-Tate

Temporal Representation:

The samples were collected between the days of 2011-06-28 and 2011-10-18 .

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment E. coli Monitoring Quality Assurance Project Plan (QAPP)

QAPP Information Reference(s):

UC Davis - US Forest Service Grazing Allotment Water Quality Monitoring Quality Assurance Project Plan (QAPP)