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

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	Bourland Creek (Tuolumne County)
Water Body ID:	CAR5364002320101020160322
Water Body Type:	River & Stream


DECISION ID	161514	Region 5
Bourland Creek (Tuolumne County)

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)(2020)
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. Historical bacteria LOEs (pre-2010 data) have been removed and data has been compared to the newer E. coli bacteria water quality objective.

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 161514, Indicator Bacteria	Region 5
Bourland Creek (Tuolumne County)

LOE ID:

329446

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

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 Stanislaus Forest:Bacteria Contamination,Livestock data for Bourland Creek (Tuolumne County) to determine beneficial use support and the results are as follows: 1 of the 2 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 Stanislaus National Forest CSERC for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use 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): BouC_BoM_2 (Bourland Creek downstream of Bourland Meadow Lower Control Site).

Temporal Representation:

The samples were collected between the days of 2021-06-22 and 2021-07-13 .

Environmental Conditions:

QAPP Information:

CSERC_QAPP_2021 - Stanislaus Forest:Bacteria Contamination,Livestock

QAPP Information Reference(s):

SWRCB - Region5 - CSERC_QAPP_2021 - Stanislaus Forest:Bacteria Contamination,Livestock - 402645

Line of Evidence (LOE) for Decision ID 161514, Indicator Bacteria	Region 5
Bourland Creek (Tuolumne County)

LOE ID:

194434

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 Bourland Creek (Tuolumne 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:

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): BouC_BoM_2

Temporal Representation:

The samples were collected between the days of 2017-06-23 and 2018-08-15 .

Environmental Conditions:

QAPP Information:

Central Sierra Environmental Resource Center. 2010. QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest., Central Sierra Environmental Resource Center. 2016. QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest., Central Sierra Environmental Resource Center (CSERC). 2017. QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest., Central Sierra Environmental Resource Center. 2018. QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest.

QAPP Information Reference(s):

QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest

QAPP Information Reference(s):

QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest

QAPP Information Reference(s):

QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest

QAPP Information Reference(s):

QAPP for Surface Water Ambient Monitoring Project in the Stanislaus National Forest

Line of Evidence (LOE) for Decision ID 161514, Indicator Bacteria	Region 5
Bourland Creek (Tuolumne County)

LOE ID:

194518

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 Bourland Creek (Tuolumne County) to determine beneficial use support and the results are as follows: 0 of the 3 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): BOUC_BOM

Temporal Representation: