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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Squaw Creek
Water Body ID:	CAR6352001119980805095744
Water Body Type:	River & Stream


DECISION ID	162139	Region 6
Squaw Creek

Pollutant:	Alkalinity as CaCO3
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 3.2 of the Listing Policy. Under section 3.2 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. Zero of 24 samples exceed the guideline. 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. Zero of 24 samples exceed the guideline and this does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 162139, Alkalinity as CaCO3	Region 6
Squaw Creek

LOE ID:

98116

Pollutant:

Alkalinity as CaCO3

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Alkalinity as CaCO3.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The National Recommended Water Quality Criteria for Alkalinity as CaCO3 for the protection of freshwater aquatic life is not less than 20000 ug/L. (National Recommended Water Quality Criteria 2016)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162139, Alkalinity as CaCO3	Region 6
Squaw Creek

LOE ID:

337855

Pollutant:

Alkalinity as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).

Objective/Criterion Reference:

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

Evaluation Guideline:

The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170401	Region 6
Squaw Creek

Pollutant:	Ammonia
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:	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 170401, Ammonia	Region 6
Squaw Creek

LOE ID:

338285

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Ammonia as N, Unionized.

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The un-ionized ammonia water quality objective to protect aquatic life in freshwater is temperature and pH dependent and is calculated according to the equation for the four-day criterion defined in Chapter 3 of The Water Quality Control Plan for the Lahontan Region.

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: MTRSQCR00 (Squaw Creek (TRWC)).

Temporal Representation:

The samples were collected between the dates of 2018-05-19 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 170401, Ammonia	Region 6
Squaw Creek

LOE ID:

98689

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 7 samples exceeded the water quality standard for Ammonia as N.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2011-05-14 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.


DECISION ID	162135	Region 6
Squaw Creek

Pollutant:	Fluoride
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:	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 162135, Fluoride	Region 6
Squaw Creek

LOE ID:

338638

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for Fluoride.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Fluoride incorporated by reference in the Water Quality Control Plan, Lahontan Region is 2 mg/L (Water Quality Control Plan, Lahontan Region).

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: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2019-07-17

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162135, Fluoride	Region 6
Squaw Creek

LOE ID:

338580

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Fluoride.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Fluoride incorporated by reference in the Water Quality Control Plan, Lahontan Region is 2 mg/L (Water Quality Control Plan, Lahontan Region).

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: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162135, Fluoride	Region 6
Squaw Creek

LOE ID:

338613

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Fluoride.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Waters designated as AGR shall not contain concentrations of chemical constituents in amounts that adversely affect the water for beneficial uses (i.e., agricultural purposes). (Water Quality Control Plan, Lahontan Region)

Objective/Criterion Reference:

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

Evaluation Guideline:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. A 1 mg/L criteria is the recommended maximum concentration of Fluoride in irrigation water.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162135, Fluoride	Region 6
Squaw Creek

LOE ID:

98167

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Fluoride.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Fluoride incorporated by reference in the Water Quality Control Plan, Lahontan Region is 2 mg/L (Water Quality Control Plan, Lahontan Region).

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(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162135, Fluoride	Region 6
Squaw Creek

LOE ID:

338568

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 1 of 11 samples exceeded the water quality threshold for Fluoride.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2019-07-17

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170402	Region 6
Squaw Creek

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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of the 31 samples exceed the objective. (Fecal coliform lines of evidence used in previous indicator bacteria decisions in the Lahontan Region have been removed from decisions, starting in the 2026 Integrated Report, because the Lahontan Region's fecal coliform 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. Zero of the 31 samples exceed the objective, and this does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170402, Indicator Bacteria	Region 6
Squaw Creek

LOE ID:

99873

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and the results are as follows: 0 of the 9 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 the SWAMP RWB6 Monitoring (tissue and water).

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): 635SQLB01

Temporal Representation:

The samples were collected between the days of 2014-09-23 and 2015-09-16 .

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 170402, Indicator Bacteria	Region 6
Squaw Creek

LOE ID:

99999

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 RWB6_BACT_Monitoring data for Squaw Creek to determine beneficial use support and the results are as follows: 0 of the 6 samples exceeded the geomean water quality standard for E. coli. This is a six week rolling geomean that is calculated weekly.

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 six-week rolling GEOMETRIC MEAN (GM) of Escherichia coli (E. coli) not to exceed 100 colony forming units per 100 milliliters (cfu/100 mL) (calculated weekly).

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): 635SQLB01

Temporal Representation:

The samples were collected between the days of 2013-08-05 and 2014-10-03 .

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 170402, Indicator Bacteria	Region 6
Squaw Creek

LOE ID:

99982

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 RWB6_BACT_Monitoring data for Squaw Creek to determine beneficial use support and the results are as follows: 0 of the 5 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:

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): 635SQLB01

Temporal Representation:

The samples were collected between the days of 2013-08-05 and 2014-10-03 .

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 170402, Indicator Bacteria	Region 6
Squaw Creek

LOE ID:

336868

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and the results are as follows: 0 of the 11 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:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

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): 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the days of 2016-02-22 and 2021-11-18 .

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	102117	Region 6
Squaw Creek

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
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:	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. Two lines of evidence are available in the administrative record to assess this pollutant. 0 of 14 samples exceed the water quality objective. 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. 0 of 14 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 102117, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 6
Squaw Creek

LOE ID:

98550

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for nitrate + nitrite (as N) that is incorporated by reference in the Water Quality Control Plan, Lahontan Region is 10.0 mg/L (Water Quality Control Plan, Lahontan Region).

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(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 102117, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 6
Squaw Creek

LOE ID:

97384

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality standard for Nitrate + Nitrite as N.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2011-05-14 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.


DECISION ID	170419	Region 6
Squaw Creek

Pollutant:	Nitrogen
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:	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 170419, Nitrogen	Region 6
Squaw Creek

LOE ID:

96839

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 were collected by Lahontan SWAMP staff for routine regional monitoring at one location in 2014 and 2015. Concentrations in the raw data ranged from 0.0298 to 0.0918 mg/L. Two annual averages can be computed, both of which attain the water quality objective for total nitrogen.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for total nitrogen in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.18 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

Squaw Creek is a tributary of the Truckee River downstream of Lake Tahoe. Its watershed includes residential, commercial and recreational (ski resort and golf course) development. Part of the creek channel has been hydromodified. Lahontan staff completed the Squaw Creek sediment TMDL in 2006 and the plan was accepted by USEPA in 2007.

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 170419, Nitrogen	Region 6
Squaw Creek

LOE ID:

343160

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 4 samples exceeded the water quality threshold for Nitrogen, Total

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total in this water body is 0.18 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2019-07-17

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	162136	Region 6
Squaw Creek

Pollutant:	Oxygen, Dissolved
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Seventeen lines of evidence are available in the administrative record to assess this parameter: Seven which assess dissolved oxygen concentration data and 10 which assess dissolved oxygen percent saturation data. Three of 70 samples are below the objective for minimum dissolved oxygen concentration. Eight of 66 samples are below the objective for minimum dissolved oxygen percent saturation. 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. Three of 70 samples are below the objective for minimum dissolved oxygen concentration. Eight of 66 samples are below the objective for minimum dissolved oxygen percent saturation. This does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

130150

Pollutant:

Oxygen, Dissolved

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 Truckee River Water Quality Monitoring Plan data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) (BIO-SC1, BIO-SC2, BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2012-07-23 and 2014-06-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Water Quality Monitoring Plan

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

130082

Pollutant:

Oxygen, Dissolved

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 Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 23 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2010-09-25 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

339334

Pollutant:

Oxygen, Dissolved

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.

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: BIO-SC1 (BIO-SC1 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-20 and 2018-08-02

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

339502

Pollutant:

Oxygen, Dissolved

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.

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: BIO-SC2 (BIO-SC2 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

339499

Pollutant:

Oxygen, Dissolved

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 5 of 17 samples exceeded the water quality threshold for Oxygen, Saturation.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.

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: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-06-27 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

339484

Pollutant:

Oxygen, Dissolved

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.

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: BIO-SC3 (BIO-SC3 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351309

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 17 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 7 (mg/L), (as a Min).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-06-27 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351372

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data to determine beneficial use support and results are as follows:
0 of 4 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 7 (mg/L), (as a Min).

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: BIO-SC1 Squaw Creek (BIO-SC1)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351369

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data to determine beneficial use support and results are as follows:
1 of 4 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 7 (mg/L), (as a Min).

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: BIO-SC3 Squaw Creek (BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351373

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 7 (mg/L), (as a Min).

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: BIO-SC2 Squaw Creek (BIO-SC2)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351344

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
2 of 12 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 7 (mg/L), (as a Min).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-06-22 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351192

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 16 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 80 (%), (as a Min).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-06-27 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351252

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data to determine beneficial use support and results are as follows:
0 of 2 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 80 (%), (as a Min).

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: BIO-SC1 Squaw Creek (BIO-SC1)

Temporal Representation:

The samples were collected between the dates of 2016-07-20 and 2018-08-02

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351249

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data to determine beneficial use support and results are as follows:
1 of 3 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 80 (%), (as a Min).

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: BIO-SC3 Squaw Creek (BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351253

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data to determine beneficial use support and results are as follows:
0 of 3 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 80 (%), (as a Min).

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: BIO-SC2 Squaw Creek (BIO-SC2)

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

351243

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
1 of 11 samples fell below the minimum water quality threshold for Oxygen, Dissolved

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Oxygen, Dissolved in this water body is 80 (%), (as a Min).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-06-22 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162136, Oxygen, Dissolved	Region 6
Squaw Creek

LOE ID:

130151

Pollutant:

Oxygen, Dissolved

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 Truckee River Water Quality Monitoring Plan data for Squaw Creek to determine beneficial use support and results are as follows: 1 of 6 samples exceeded the water quality standard for Oxygen, Saturation.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) (BIO-SC1, BIO-SC2, BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2012-07-23 and 2014-06-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Water Quality Monitoring Plan

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014


DECISION ID	162138	Region 6
Squaw Creek

Pollutant:	Sodium
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant, two that assess for the AGR use and two that assess for the MUN use. Zero of the 23 samples exceed the guideline for AGR and zero of 23 samples exceed the guideline for MUN. 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. Zero of the 23 samples exceed the guideline for AGR and zero of 23 samples exceed the guideline for MUN and this does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 162138, Sodium	Region 6
Squaw Creek

LOE ID:

98598

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Sodium.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the sodium threshold of 69 mg/L, agricultural uses of water should not be limited.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162138, Sodium	Region 6
Squaw Creek

LOE ID:

340294

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 17 samples exceeded the water quality threshold for Sodium.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 mg/l.

Guideline Reference:

2012 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162138, Sodium	Region 6
Squaw Creek

LOE ID:

97173

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Sodium.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 mg/l.

Guideline Reference:

2012 Edition of the Drinking Water Standards and Health Advisories

Spatial Representation:

The samples were collected at 1 monitoring site(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162138, Sodium	Region 6
Squaw Creek

LOE ID:

340295

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 17 samples exceeded the water quality threshold for Sodium.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the sodium threshold of 69 mg/L, agricultural uses of water should not be limited.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170417	Region 6
Squaw Creek

Pollutant:	Specific Conductivity
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess this pollutant. Zero of 49 samples exceed the water quality objective. 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. Zero of 49 samples exceed the water quality objective, and this does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

98637

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).

Objective/Criterion Reference:

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

Evaluation Guideline:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's \Chemical Constituents\" objective. The California Secondary MCL for specific conductivity is 900 uS/cm."

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 3 monitoring site(s) (BIO-SC1, BIO-SC2, BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2012-07-23 and 2014-06-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Water Quality Monitoring Plan

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

340581

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The California Secondary MCL for specific conductivity is 900 uS/cm.

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC3 (BIO-SC3 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

340586

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 17 samples exceeded the water quality threshold for SpecificConductivity.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

97263

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

340400

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for SpecificConductivity.

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: MTRSQCR00 (Squaw Creek (TRWC)).

Temporal Representation:

The samples were collected between the dates of 2017-06-22 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

340658

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC1 (BIO-SC1 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-20 and 2018-08-02

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 170417, Specific Conductivity	Region 6
Squaw Creek

LOE ID:

340415

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC2 (BIO-SC2 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639


DECISION ID	163682	Region 6
Squaw Creek

Pollutant:	Total Dissolved Solids
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 section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Three lines of evidence, two which assess TDS data for the COLD beneficial use and one which assesses TDS data for the MUN beneficial use, are available in the administrative record to assess this pollutant. Zero of 3 samples exceeds the California Maximum Contaminant Level (MCL) for the MUN beneficial use assessment. One of 3 annual average samples exceed the objective for the COLD beneficial use assessment. 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 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. Zero of 3 samples exceeded the California MCL and 1 of 3 samples exceed the site specific objective assessed for the COLD beneficial use. These sample sizes are insufficient to determine if the beneficial uses are fully supported using table 3.1. 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 163682, Total Dissolved Solids	Region 6
Squaw Creek

LOE ID:

26288

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. TDS concentrations were 29, 38, and 44 mg/L. The mean concentration for this month was 37 mg/L The water quality objective was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for Total Dissolved Solids (TDS), from Lahontan Basin Plan Table 3-11, is 85 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 163682, Total Dissolved Solids	Region 6
Squaw Creek

LOE ID:

133447

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 were collected by Lahontan SWAMP staff for routine regional monitoring at one location in 2014 and 2015. Concentrations in the raw data ranged from 57 to 214 mg/L. Two annual averages can be computed, one of which exceed the water quality objective for total dissolved solids.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for sulfates in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 85.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 163682, Total Dissolved Solids	Region 6
Squaw Creek

LOE ID:

343418

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
2 of 3 samples exceeded the water quality threshold for Total Dissolved Solids

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Total Dissolved Solids in this water body is 85 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 163682, Total Dissolved Solids	Region 6
Squaw Creek

LOE ID:

343411

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
3 of 4 samples exceeded the water quality threshold for Total Dissolved Solids

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Total Dissolved Solids in this water body is 85 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2017-09-25 and 2020-02-25

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	163683	Region 6
Squaw Creek

Pollutant:	Turbidity
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. One of the 20 samples exceed the water quality objective. 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. One of the 20 samples exceed the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 163683, Turbidity	Region 6
Squaw Creek

LOE ID:

97423

Pollutant:

Turbidity

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The objective for turbidity in Squaw Creek, as stipulated in the Lahontan Basin Plan Chapter 3-8, is a mean of monthly mean value not to exceed 3 Nephelometric Turbidity Units (NTU).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2010-09-25 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 163683, Turbidity	Region 6
Squaw Creek

LOE ID:

97246

Pollutant:

Turbidity

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Turbidity.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The objective for turbidity in Squaw Creek, as stipulated in the Lahontan Basin Plan Chapter 3-8, is a mean of monthly mean value not to exceed 3 Nephelometric Turbidity Units (NTU).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 163683, Turbidity	Region 6
Squaw Creek

LOE ID:

343435

Pollutant:

Turbidity

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 7 samples exceeded the water quality threshold for Turbidity

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Turbidity in this water body is 3 (NTU), (as a MOMM).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 163683, Turbidity	Region 6
Squaw Creek

LOE ID:

343445

Pollutant:

Turbidity

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
1 of 4 samples exceeded the water quality threshold for Turbidity

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Turbidity in this water body is 3 (NTU), (as a MOMM).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-05-20 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.


DECISION ID	162137	Region 6
Squaw Creek

Pollutant:	pH
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:	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 162137, pH	Region 6
Squaw Creek

LOE ID:

129710

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

0 of 0 samples exceeded the water quality standard for pH. Although pH data does exist for this waterbody, the objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality standards could not be made.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's regionwide objective for pH states: \In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.\""

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(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162137, pH	Region 6
Squaw Creek

LOE ID:

340200

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 Truckee River Water Quality Monitoring Plan data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'

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: BIO-SC1 (BIO-SC1 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-20 and 2018-08-02

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

129551

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2010-09-25 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

129789

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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(s) (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2014-09-23 and 2015-12-09

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 162137, pH	Region 6
Squaw Creek

LOE ID:

129683

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) (BIO-SC1, BIO-SC2, BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2012-07-23 and 2014-06-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Water Quality Monitoring Plan

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

129739

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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(s) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2010-09-25 and 2016-09-22

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339592

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 SWAMP RWB6 Monitoring data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 18 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339869

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: BIO-SC1 (BIO-SC1 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-20 and 2018-08-02

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339995

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Truckee River Water Quality Monitoring Plan data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: BIO-SC2 (BIO-SC2 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339918

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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: 635SQLB01 (Squaw Creek, above Truckee River).

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2022-02-16

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339915

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Truckee River Watershed Council data for Squaw Creek to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: MTRSQCR00 (Squaw Creek (TRWC)).

Temporal Representation:

The samples were collected between the dates of 2017-06-22 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339634

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: BIO-SC3 (BIO-SC3 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339872

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: BIO-SC2 (BIO-SC2 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

340207

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: BIO-SC3 (BIO-SC3 Squaw Creek).

Temporal Representation:

The samples were collected between the dates of 2016-07-19 and 2020-08-03

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

339914

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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: MTRSQCR00 (Squaw Creek (TRWC)).

Temporal Representation:

The samples were collected between the dates of 2017-06-22 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 162137, pH	Region 6
Squaw Creek

LOE ID:

129685

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) (BIO-SC1, BIO-SC2, BIO-SC3)

Temporal Representation:

The samples were collected between the dates of 2012-07-23 and 2014-06-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan (QAPP) for Truckee River Water Quality Monitoring Plan

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014


DECISION ID	171776	Region 6
Squaw Creek

Pollutant:	Benthic Community Effects
Final Listing Decision:	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
Sources:	A Source Unknown
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects. Five lines of evidence evaluating benthic-macroinvertebrate bioassessment data are available in the administrative record to assess this indicator. Eight of twenty-three benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. Additionally, there are associated pollutant impairments on the waterbody (including but not necessarily limited to chloride, nitrogen, and phosphorus). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing Benthic Community Effects in this waterbody segment 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. 8 of 23 benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. Therefore, this water body is exceeding the water quality threshold for the protection of the COLD beneficial use. 4. Pursuant to section 3.9 of the Listing Policy, the water segment has associated pollutant(s) samples that exceed water quality objectives. 5. 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 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96841

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 were collected by Lahontan SWAMP staff for routine regional monitoring at one location in 2014 and 2015. Concentrations in the raw data ranged from 10.8 to 85.6 mg/L. Two annual averages can be computed, both of which exceed the water quality objective for phosphorous.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for sulfates in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 25.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96840

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 were collected by Lahontan SWAMP staff for routine regional monitoring at one location in 2014 and 2015. Concentrations in the raw data ranged from non-detect to 0.006 mg/L. Two annual averages can be computed, both of which attain the water quality objective for phosphorous.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for phosphorus in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.02 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343264

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
2 of 6 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Phosphorus as P in this water body is 0.02 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

26284

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. NO3-N concentrations were 0.12, 0.14, and 0.23 mg/L. The mean concentration for this month was 0.16 mg/L, in violation of the objective.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for nitrate (NO3-N), from Lahontan Basin Plan Table 3-11, is 0.05 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343038

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Nitrate as N

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrate as N in this water body is 0.05 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2019-07-17 and 2020-02-25

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96838

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 were collected by Lahontan SWAMP staff for routine regional monitoring at one location in 2014 and 2015. Concentrations in the raw data ranged from 2.09 to 5.66 mg/L. Two annual averages can be computed, both of which exceed the water quality objective for chloride.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for chloride in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 3.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

342805

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
3 of 6 samples exceeded the water quality threshold for Chloride

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Chloride in this water body is 3 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

26279

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. Chloride concentrations were 1.7, 1.8, and 1.8 mg/L. The mean concentration for this month was 1.8 mg/L The water quality objective was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for chloride, from Lahontan Basin Plan Table 3-11, is 3.0 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

352923

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for BIO-SC3 to determine beneficial use support and the results are as follows: 0 of 5 samples exceeded the water quality standard. CSCI scores were from 0.963968816 to 1.049510107 .

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Lahontan Basin Plan)

Objective/Criterion Reference:

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

Evaluation Guideline:

The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rhen, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.)

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC3 (BIO-SC3 Squaw Creek).

Temporal Representation:

Samples were collected from 2012-07-23 to 2020-08-03.

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

352921

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for BIO-SC1 to determine beneficial use support and the results are as follows: 4 of 5 samples exceeded the water quality standard. CSCI scores were from 0.775140981 to 0.851333649 .

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC1 (BIO-SC1 Squaw Creek).

Temporal Representation:

Samples were collected from 2012-07-25 to 2020-08-03.

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

352922

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for BIO-SC2 to determine beneficial use support and the results are as follows: 3 of 5 samples exceeded the water quality standard. CSCI scores were from 0.75 to 1.13543373 .

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Water Quality Monitoring Plan for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The samples were collected at 1 monitoring site: BIO-SC2 (BIO-SC2 Squaw Creek).

Temporal Representation:

Samples were collected from 2012-07-24 to 2020-08-03.

Environmental Conditions:

QAPP Information:

TRWQMP QAPP Equivalent

QAPP Information Reference(s):

Lahontan Water Board - TRWQMP_QAPP equivalent - Truckee River Water Quality Monitoring Plan - 402639

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96503

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The CSCI scores from this water body were
0.851333649
0.775140981
1.13543373
1.031751119
1.049510107
0.963968816

One of the six scores is not meeting the water quality objective.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Water Quality Monitoring Plan.

SWAMP Data:

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

Samples collected from the following stations:
BIO-SC1
BIO-SC2
BIO-SC3

Temporal Representation:

Samples collected on the following dates:
6/27/2014
7/25/2012
7/24/2012
6/27/2014
7/23/2012
6/26/2014

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Watershed Council

QAPP Information Reference(s):

Sampling and Analysis Plan for Implementation of the Truckee River Water Quality Monitoring Plan Water Year 2014

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96781

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

The site had a CSCI score of 1.088256 and 1.20989. This score indicates that this site is supporting aquatic life beneficial uses and that the water quality objective is met. Additionally, this water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP Perennial Stream Surveys.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

Samples collected at site 635SQN001
.

Temporal Representation:

Samples collected on 8/28/2000 and 7/9/2001.

Environmental Conditions:

QAPP Information:

QAPP for SWAMP Perennial Stream Surveys

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 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96843

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 were collected by the Truckee River Watershed Council between May 2011 and September 2016. Concentrations in the raw data ranged from 0.009 to 0.02 mg/L. Six annual averages can be computed, none of which exceed the water quality objective for phosphorus.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site specific objective for phosphorous in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.02 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, MTRSQCR00, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in in May of 2011, 2012, 2013; in May and September of 2014; in May and June of 2015; and in May and September of 2016.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the Truckee River Monitoring Plan QAPP.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343277

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
1 of 4 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council 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 0.02 (mg/L), (as a MOMMPR).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-05-20 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

96842

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 were collected by the Truckee River Watershed Council between May 2011 and September 2016. Concentrations in the raw data ranged from 0.035 to 0.156 mg/L. Six annual averages can be computed, one of which exceed the water quality objective for TKN in 2016 (result=0.156 mg/L).

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site specific objective for total kjeldahl nitrogen (TKN) in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.13 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, MTRSQCR00, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in in May of 2011, 2012, 2013; in May and September of 2014; in May and June of 2015; and in May and September of 2016.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the Truckee River Monitoring Plan QAPP.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343510

Pollutant:

Total Kjeldahl Nitrogen (TKN)

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Nitrogen, Total Kjeldahl

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total Kjeldahl in this water body is 0.13 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343512

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
2 of 4 samples exceeded the water quality threshold for Nitrogen, Total Kjeldahl

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total Kjeldahl in this water body is 0.13 (mg/L), (as a MOMMPR).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-05-20 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343346

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
2 of 5 samples exceeded the water quality threshold for Sulfate

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Sulfate in this water body is 25 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2020-02-25

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

26286

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. Sulfate concentrations were 9.2, 10.4 and 10.4 mg/L. The mean concentration for this month was 10.0 mg/L The water quality objective was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for sulfate, from Lahontan Basin Plan Table 3-11, is 25.0 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 171776, Benthic Community Effects	Region 6
Squaw Creek

LOE ID:

343347

Pollutant:

Sulfates

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Sulfate

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Sulfate in this water body is 25 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	163679	Region 6
Squaw Creek

Pollutant:	Chloride
Final Listing Decision:	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
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant, one that assesses for MUN and three that assess for the COLD use. Zero of 3 samples exceed the objective for MUN and five of 9 samples exceed the objective for COLD. 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. Five of 9 samples exceed the objective for COLD and this exceeds the allowable frequency listed in Table 3.2 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 163679, Chloride	Region 6
Squaw Creek

LOE ID:

96838

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for chloride in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 3.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 163679, Chloride	Region 6
Squaw Creek

LOE ID:

26279

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. Chloride concentrations were 1.7, 1.8, and 1.8 mg/L. The mean concentration for this month was 1.8 mg/L The water quality objective was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for chloride, from Lahontan Basin Plan Table 3-11, is 3.0 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 163679, Chloride	Region 6
Squaw Creek

LOE ID:

26281

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. Chloride concentrations were 1.7, 1.8, and 1.8 mg/L. The MCL was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data..

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 163679, Chloride	Region 6
Squaw Creek

LOE ID:

342805

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
3 of 6 samples exceeded the water quality threshold for Chloride

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Chloride in this water body is 3 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170405	Region 6
Squaw Creek

Pollutant:	Nitrogen, Nitrate
Final Listing Decision:	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
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. Two lines of evidence are available in the administrative record to assess this pollutant. Two of the two 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. Two of the two 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 170405, Nitrogen, Nitrate	Region 6
Squaw Creek

LOE ID:

26284

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. NO3-N concentrations were 0.12, 0.14, and 0.23 mg/L. The mean concentration for this month was 0.16 mg/L, in violation of the objective.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for nitrate (NO3-N), from Lahontan Basin Plan Table 3-11, is 0.05 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 170405, Nitrogen, Nitrate	Region 6
Squaw Creek

LOE ID:

343038

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Nitrate as N

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrate as N in this water body is 0.05 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2019-07-17 and 2020-02-25

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	163680	Region 6
Squaw Creek

Pollutant:	Phosphorus
Final Listing Decision:	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
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. Two lines of evidence are available in the administrative record to assess this pollutant. Two of the 8 samples exceed the water quality 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. Two of the 8 samples exceed the water quality 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 163680, Phosphorus	Region 6
Squaw Creek

LOE ID:

343264

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
2 of 6 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Phosphorus as P in this water body is 0.02 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 163680, Phosphorus	Region 6
Squaw Creek

LOE ID:

343277

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Truckee River Watershed Council data to determine beneficial use support and results are as follows:
1 of 4 samples exceeded the water quality threshold for Phosphorus as P

Data Reference:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council 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 0.02 (mg/L), (as a MOMMPR).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-05-20 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 163680, Phosphorus	Region 6
Squaw Creek

LOE ID:

96840

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for phosphorus in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.02 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 163680, Phosphorus	Region 6
Squaw Creek

LOE ID:

96843

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site specific objective for phosphorous in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.02 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, MTRSQCR00, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in in May of 2011, 2012, 2013; in May and September of 2014; in May and June of 2015; and in May and September of 2016.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the Truckee River Monitoring Plan QAPP.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.


DECISION ID	163681	Region 6
Squaw Creek

Pollutant:	Sulfates
Final Listing Decision:	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
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Five of the ten samples exceed the water quality 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. Five of the ten samples exceed the water quality objective, and this exceeds the allowable frequency listed in Table 3.2 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 163681, Sulfates	Region 6
Squaw Creek

LOE ID:

343347

Pollutant:

Sulfates

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Sulfate

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Sulfate in this water body is 25 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 163681, Sulfates	Region 6
Squaw Creek

LOE ID:

26286

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for three samples collected on December 19, 2006 at three different stations in Squaw Creek. Sulfate concentrations were 9.2, 10.4 and 10.4 mg/L. The mean concentration for this month was 10.0 mg/L The water quality objective was not exceeded.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for sulfate, from Lahontan Basin Plan Table 3-11, is 25.0 mg/L as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Three stations (D-1, D-2 and D-3) were sampled.

Temporal Representation:

All three samples were collected on the same date, December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 163681, Sulfates	Region 6
Squaw Creek

LOE ID:

96841

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site specific objective for sulfates in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 25.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, 635SQLB01, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in September and October 2014 and in January, April, September and December 2015.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the SWAMP QAPP.

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 163681, Sulfates	Region 6
Squaw Creek

LOE ID:

343346

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
2 of 5 samples exceeded the water quality threshold for Sulfate

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Sulfate in this water body is 25 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2016-02-22 and 2020-02-25

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	170418	Region 6
Squaw Creek

Pollutant:	Total Kjeldahl Nitrogen (TKN)
Final Listing Decision:	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
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. Four of the 12 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. Four of the 12 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 170418, Total Kjeldahl Nitrogen (TKN)	Region 6
Squaw Creek

LOE ID:

96842

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Truckee River Watershed Council.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site specific objective for total kjeldahl nitrogen (TKN) in Squaw Creek, as referenced in the Lahontan Basin Plan Table 3-11, is an annual average concentration not to exceed 0.13 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected at one location, MTRSQCR00, just upstream from the confluence with the Truckee River.

Temporal Representation:

Data were collected in in May of 2011, 2012, 2013; in May and September of 2014; in May and June of 2015; and in May and September of 2016.

Environmental Conditions:

QAPP Information:

Data were collected in accordance with the Truckee River Monitoring Plan QAPP.

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.

Line of Evidence (LOE) for Decision ID 170418, Total Kjeldahl Nitrogen (TKN)	Region 6
Squaw Creek

LOE ID:

343510

Pollutant:

Total Kjeldahl Nitrogen (TKN)

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 SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Nitrogen, Total Kjeldahl

Data Reference:

Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total Kjeldahl in this water body is 0.13 (mg/L), (as a MOMMPR).

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: Squaw Creek, above Truckee River (635SQLB01)

Temporal Representation:

The samples were collected between the dates of 2017-11-13 and 2021-11-18

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 170418, Total Kjeldahl Nitrogen (TKN)	Region 6
Squaw Creek

LOE ID:

343512

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Benthic, Field, Habitat, WQ from the Truckee River Watershed Council for the 2026 Integrated Report in Region 6

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Nitrogen, Total Kjeldahl in this water body is 0.13 (mg/L), (as a MOMMPR).

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: Squaw Creek (TRWC) (MTRSQCR00)

Temporal Representation:

The samples were collected between the dates of 2017-05-20 and 2020-10-03

Environmental Conditions:

QAPP Information:

QAPP for Truckee River Monitoring Plan

QAPP Information Reference(s):

Quality Assurance Project Plan (QAPP) for Truckee River Monitoring Plan.


DECISION ID	69734	Region 6
Squaw Creek

Pollutant:	Iron
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)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: 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. The single sample does not exceed California Maximum Contaminant Level (MCL) or the site-specific water quality objective. 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 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 do not satisfy the data quantity requirements of section 6.1.5 or Table 3.1 of the Policy. 3. The single sample did not exceed the MCL or the site specific objective and this does not exceed 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:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 69734, Iron	Region 6
Squaw Creek

LOE ID:

26282

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Valley Public Service District (a drinking water purveyor) submitted laboratory results for one sample collected at Station D-3 in Squaw Creek. The iron concentration was 116 ug/L. The objective was not violated.

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site-specific objective for iron, from Lahontan Basin Plan Table 3-11, is 0.13 mg/L ( equal to 130 ug/L) as a mean of monthly means for the period of record.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Iron was determined for one sample from Station D-3.

Temporal Representation:

One sample was collected on December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 69734, Iron	Region 6
Squaw Creek

LOE ID:

26283

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Data Reference:

2007. Chemical Report dated 01/08/07 on samples collected from Squaw Creek on 12/19/06 by the Squaw Valley Public Service District

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for iron is 300 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Iron was determined for one sample from Station D-3.

Temporal Representation:

One sample was collected on December 19, 2006.

Environmental Conditions:

QAPP Information:

The data were analyzed by Cranmer Analytical Laboratory, a California state certified laboratory. Some quality assurance information was provided with the data.

QAPP Information Reference(s):


DECISION ID	71560	Region 6
Squaw Creek

Pollutant:	Sedimentation/Siltation
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)(2016)
Revision Status	Original
Sources:	Construction/Land Development \| Drainage/Filling Of Wetlands \| Highway Maintenance and Runoff \| Hydromodification \| Natural Sources \| Nonpoint Source \| Other Urban Runoff \| Recreational and Tourism Activities (non-boating)
TMDL Name:	Squaw Creek Sediment
TMDL Project Code:	186
Date TMDL Approved by USEPA:	07/27/2007
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged and is as follows: 303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.

Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 71560, Sedimentation/Siltation	Region 6
Squaw Creek

LOE ID:

2869

Pollutant:

Sediment

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The Squaw Creek Sediment TMDL was approved by the RWQCB in 2006 and subsequently approved by USEPA.
Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):