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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	West Barry Creek
Water Body ID:	CAR6372006020171227036711
Water Body Type:	River & Stream


DECISION ID	169015	Region 6
West Barry Creek

Pollutant:	Phosphorus
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 169015, Phosphorus	Region 6
West Barry Creek

LOE ID:

348070

Pollutant:

Phosphorus

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 Susanville Indian Rancheria, California (Tribal) data to determine beneficial use support and results are as follows:
0 of 2 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Phosphorus as P in this water body is 0.25 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek UR1 (SIR_WQX-SW-WBC-UR1)

Temporal Representation:

The samples were collected between the dates of 2021-03-22 and 2022-02-28

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678

Line of Evidence (LOE) for Decision ID 169015, Phosphorus	Region 6
West Barry Creek

LOE ID:

348069

Pollutant:

Phosphorus

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 Susanville Indian Rancheria, California (Tribal) data to determine beneficial use support and results are as follows:
0 of 1 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Phosphorus as P in this water body is 0.25 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek LR2 (SIR_WQX-SW-WBC-LR2)

Temporal Representation:

The samples were collected between the dates of 2022-02-28 and 2022-09-30

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678

Line of Evidence (LOE) for Decision ID 169015, Phosphorus	Region 6
West Barry Creek

LOE ID:

348068

Pollutant:

Phosphorus

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Phosphorus as P in this water body is 0.25 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek LR1 (SIR_WQX-SW-WBC-LR1)

Temporal Representation:

The samples were collected between the dates of 2021-03-22 and 2022-09-30

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678


DECISION ID	170295	Region 6
West Barry Creek

Pollutant:	Nitrogen
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
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 placement on the CWA 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. Three lines of evidence are available in the administrative record to assess this pollutant. Six of the 7 samples exceed the objective. 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 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. Six of 7 samples exceed the objective and 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170295, Nitrogen	Region 6
West Barry Creek

LOE ID:

348061

Pollutant:

Total Nitrogen as N

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 Susanville Indian Rancheria, California (Tribal) data to determine beneficial use support and results are as follows:
2 of 3 samples exceeded the water quality threshold for Nitrogen, Total

Data Reference:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total in this water body is 0.65 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek LR1 (SIR_WQX-SW-WBC-LR1)

Temporal Representation:

The samples were collected between the dates of 2015-01-08 and 2022-02-28

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678

Line of Evidence (LOE) for Decision ID 170295, Nitrogen	Region 6
West Barry Creek

LOE ID:

348063

Pollutant:

Total Nitrogen as N

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 Susanville Indian Rancheria, California (Tribal) data to determine beneficial use support and results are as follows:
2 of 2 samples exceeded the water quality threshold for Nitrogen, Total

Data Reference:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total in this water body is 0.65 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek UR1 (SIR_WQX-SW-WBC-UR1)

Temporal Representation:

The samples were collected between the dates of 2015-07-23 and 2021-06-08

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678

Line of Evidence (LOE) for Decision ID 170295, Nitrogen	Region 6
West Barry Creek

LOE ID:

348062

Pollutant:

Total Nitrogen as N

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total in this water body is 0.65 (mg/L), (as a Mean).

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: West Barry Creek LR2 (SIR_WQX-SW-WBC-LR2)

Temporal Representation:

The samples were collected between the dates of 2015-01-08 and 2022-02-28

Environmental Conditions:

QAPP Information:

Susanville Tribal QAPP

QAPP Information Reference(s):

Regional Board Region 6 - Susanville Tribal QAPP - Susanville Indian Rancheria, California (Tribal) - 402678