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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Indian Creek (Alpine County)
Water Body ID:	CAR6322001020011213104836
Water Body Type:	River & Stream


DECISION ID	170518	Region 6
Indian Creek (Alpine County)

Pollutant:	Indicator Bacteria
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the CWA section 303(d) List. Removing this water segment-pollutant combination from the CWA section 303(d) List is consistent with several factors described in the following paragraphs from the Listing Policy section 4: -All listings of water segments shall be removed from the section 303(d) list if the listing was based on faulty data, and it is demonstrated that the listing would not have occurred in the absence of such faulty data. Faulty data include, but are not limited to, typographical errors, improper quality assurance/quality control procedures, or limitations related to the analytical methods that would lead to improper conclusions regarding the water quality status of the segment. If objectives or standards have been revised and the site or water meets water quality standards, the water segment shall be removed from the section 303(d) list. The listing of a segment shall be reevaluated if the water quality standard has been changed. - This conclusion is based on the staff findings that: 1. Change of the water quality standards: The basis for listing this waterbody for indicator bacteria was exceedances of the fecal coliform water quality objective. The Region 6 fecal coliform water quality objective was removed has been removed from the Water Quality Control Plan for the Lahontan Region (Lahontan Basin Plan). 2. Faulty Data: Fecal coliform data previously used to support this listing are considered faulty data because fecal coliform bacteria do not adequately indicate risk to the MUN/REC-1 use and assessing such data would lead to improper conclusions regarding the water quality status of the segment. Fecal coliform has not been a USEPA recommended indicator bacteria for assessing water-contact recreational uses since 1986. Adoption of the statewide E. coli-based REC-1 water quality objectives is a revision of indicator bacteria to assess the REC-1 beneficial use and fecal coliform is no longer used. Additionally, assessment of fecal coliform data, which was originally used to list this waterbody with the assessment of MUN using fecal coliform data does not correspond to a water quality objective in the Lahontan Basin Plan, so associating past data with MUN is no longer appropriate. 3. The waterbody’s bacteriological water quality will be assessed using E. coli or other more representative measures, should such data be available in the future. 4. Pursuant to section 4.11 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170518, Indicator Bacteria	Region 6
Indian Creek (Alpine County)

LOE ID:

4625

Pollutant:

Pathogens

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 170518, Indicator Bacteria	Region 6
Indian Creek (Alpine County)

LOE ID:

34882

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

183

Number of Exceedances:

124

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

One hundred and twenty-four of the one hundered and eighty three (183) samples exceeded the Fecal Coliform objective

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml. 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 SW-02 Indian Creek at Diversion, SW-03 Indian Creek downstream of 1st bridge, SW-04 Indian Creek upstream of 2nd bridge and SW-10 Indian Creek @ Springmeyer Ranch.

Temporal Representation:

The samples were collected between January 2004 to June 2010.

Environmental Conditions:

QAPP Information:

The samples were collected under the South Tahoe Public Utility District Laboratory Quality Assurance Program. Monitoring and Reporting Program NO. R6T-2004-0010.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 170518, Indicator Bacteria	Region 6
Indian Creek (Alpine County)

LOE ID:

31800

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

183

Number of Exceedances:

104

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

One hundred and four (104) of the one hundered and eighty three (183) samples exceeded the Fecal Coliform objective

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Fecal Coliform concentration shall not exceed more than 40/100 ml.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at SW-02 Indian Creek at Diversion, SW-03 Indian Creek downstream of 1st bridge, SW-04 Indian Creek upstream of 2nd bridge and SW-10 Indian Creek @ Springmeyer Ranch.

Temporal Representation:

The samples were collected between January 2004 to June 2010.

Environmental Conditions:

QAPP Information:

The samples were collected under the South Tahoe Public Utility District Laboratory Quality Assurance Program. Monitoring and Reporting Program NO. R6T-2004-0010.

QAPP Information Reference(s):


DECISION ID	161939	Region 6
Indian Creek (Alpine County)

Pollutant:	Chloride
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	Unknown Nonpoint Source
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollution

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. Two lines of evidence are available in the administrative record to assess this pollutant. 262 of 865 samples exceed the water quality objective, which based on the tributary rule, applies the site-specific objective (4.0 mg/L) for the East Fork of the Carson River for Indian Creek (Alpine County). 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 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. 262 samples of the 865 exceed the objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy, which only allows for 144 exceedances for 865 observations. 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161939, Chloride	Region 6
Indian Creek (Alpine County)

LOE ID:

341182

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:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference in the Water Quality Control Plan, Lahontan Region for chloride is 250 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 161939, Chloride	Region 6
Indian Creek (Alpine County)

LOE ID:

34466

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

864

Number of Exceedances:

262

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Two-hundred and sixty-two of the 864 samples exceeded the recommended level of 250 mg/L.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Chapter 2 of the Lahontan Region's Basin Plan states Indian Creek (Alpine County) as being tributary to EAST FORK CARSON RIVER and thus, the objective for EAST FORK CARSON RIVER applies to the Indian Creek (Alpine County) water body. The site-specific objective for Chloride in Lahontan Basin Plan Table 3-14 for EAST FORK CARSON RIVER is 4.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the SW-02, SW-03, SW-04, and SW-10 stations.

Temporal Representation:

Samples were collected approximately once a month from July 1980 to June 2010.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):


DECISION ID	79079	Region 6
Indian Creek (Alpine County)

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)(2016)
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the 243 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 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. None of 243 samples exceeded the 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 79079, Ammonia	Region 6
Indian Creek (Alpine County)

LOE ID:

31724

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

243

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of the 243 samples exceed the water quality objective for un-ionized ammonia.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan objective for un-ionized ammonia is a function of pH, temperature, and the presence of salmonids.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at four locations in Indian Creek: Indian Creek @ Diversion, Indian Creek downstream of 1st bridge, Indian Creek upstream of 2nd bridge, and Indian Creek @ Springmeyer Ranch.

Temporal Representation:

Samples were collected from 2002 to 2010.

Environmental Conditions:

QAPP Information:

samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):


DECISION ID	170917	Region 6
Indian Creek (Alpine County)

Pollutant:	Benthic Community Effects
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:	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. One line of evidence evaluating benthic-macroinvertebrate bioassessment data is available in the administrative record to assess this indicator. One of one benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. One of one benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time. 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 170917, Benthic Community Effects	Region 6
Indian Creek (Alpine County)

LOE ID:

352757

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 632C10548 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the water quality standard. CSCI scores were from 0.525933883 to 0.525933883 .

Data Reference:

Benthic, Habitat from the EPA National Rivers and Streams Assessment 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: 632C10548 (Indian Creek above Dutch Valley).

Temporal Representation:

Samples were collected from 2019-07-25 to 2019-07-25.

Environmental Conditions:

QAPP Information:

Generic SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	161940	Region 6
Indian Creek (Alpine County)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161940, Chlorophyll-a	Region 6
Indian Creek (Alpine County)

LOE ID:

341218

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses.

Objective/Criterion Reference:

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

Evaluation Guideline:

North Carolina Administrative code (NCAC), Title 15A ? Environmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife).?Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	169981	Region 6
Indian Creek (Alpine County)

Pollutant:	Nitrogen, Nitrate
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two line of evidence are available in the administrative record to assess this pollutant. None of the 883 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 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. None of 883 samples exceeded the 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:	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 169981, Nitrogen, Nitrate	Region 6
Indian Creek (Alpine County)

LOE ID:

341591

Pollutant:

Nitrate as Nitrate (NO3)

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:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Nitrate incorporated by reference in the Water Quality Control Plan, Lahontan Region is 45000 ug/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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 169981, Nitrogen, Nitrate	Region 6
Indian Creek (Alpine County)

LOE ID:

31726

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

882

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of the 882 samples exceeded the water quality objective for nitrate

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan, Lahontan Basin, Objective for Municipal and Domestic Supply uses of inland surface waters states the following: waters shall not contain concentrations of inorganic chemicals in excess of the limits specified in California Code of Regulations, Title 22, Table 64431-A of section 64431 (Inorganic Chemicals). The maximum contaminant level listed in Table 64431-A for nitrate is 45.0 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at four locations in Indian Creek: SW-2 Indian Creek @ Diversion, SW-3 Indian Creek downstream of 1st bridge, SW-4 Indian Creek upstream of 2nd bridge, and SW-10 Indian Creek @ Springmeyer Ranch.

Temporal Representation:

Samples were collected from 1980 to 2010.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):


DECISION ID	170070	Region 6
Indian Creek (Alpine County)

Pollutant:	Nitrogen, Nitrite
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two line of evidence is available in the administrative record to assess this pollutant. None of the 841 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 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. None of the 841 samples exceeded the 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:	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 170070, Nitrogen, Nitrite	Region 6
Indian Creek (Alpine County)

LOE ID:

31725

Pollutant:

Nitrite as Nitrite NO2

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

840

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of the 840 samples collected exceeded the water quality objective for nitrite.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

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:

Samples were collected at four locations in Indian Creek: Indian Creek @ Diversion, Indian Creek downstream of 1st bridge, Indian Creek upstream of 2nd bridge, and Indian Creek @ Springmeyer Ranch.

Temporal Representation:

Samples were collected from 1983 to 2010.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 170070, Nitrogen, Nitrite	Region 6
Indian Creek (Alpine County)

LOE ID:

341602

Pollutant:

Nitrogen, Nitrite

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:

Data Reference:

WQX from the NWQMP 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	161942	Region 6
Indian Creek (Alpine County)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161942, Sodium	Region 6
Indian Creek (Alpine County)

LOE ID:

341783

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:

Data Reference:

WQX from the NWQMP 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 (Water Quality Control Plan, Lahontan Region).

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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 161942, Sodium	Region 6
Indian Creek (Alpine County)

LOE ID:

341796

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:

Data Reference:

WQX from the NWQMP 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:

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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	169982	Region 6
Indian Creek (Alpine County)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169982, Specific Conductivity	Region 6
Indian Creek (Alpine County)

LOE ID:

341878

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:

WQX from the NWQMP 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	161943	Region 6
Indian Creek (Alpine County)

Pollutant:	Sulfates
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:	Pollution

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. Two lines of evidence is available in the administrative record to assess this pollutant. None of the 865 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 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. None of 865 samples exceeded 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 161943, Sulfates	Region 6
Indian Creek (Alpine County)

LOE ID:

34489

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

864

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

None of the 864 samples exceeded the Secondary MCL's objective for Sulfates.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Secondary Maximum Contaminant Levels (SMCLs) apply to ambient waters under the Los Angeles's Basin Plan's "Chemical Constituents" objective. The SMCL for Sulfates (SO4) is 250 mg/L.

Objective/Criterion Reference:

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

Objective/Criterion Reference:

Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the SW-02, SW-03, SW-04, and SW-10 stations.

Temporal Representation:

Samples were collected approximately once a month from July 1980 to June 2010.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 161943, Sulfates	Region 6
Indian Creek (Alpine County)

LOE ID:

341945

Pollutant:

Sulfates

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:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference in the Water Quality Control Plan, Lahontan Region for Sulfate 250 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	161944	Region 6
Indian Creek (Alpine County)

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 161944, Turbidity	Region 6
Indian Creek (Alpine County)

LOE ID:

341974

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

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

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. The Lahontan Basin Plan also has regionwide turbidity objective for other beneficial uses that states: Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10%.

Objective/Criterion Reference:

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

Evaluation Guideline:

California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment.

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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	161941	Region 6
Indian Creek (Alpine County)

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:	Pollution

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 are available in the administrative record to assess this pollutant. The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for COLD and WARM beneficial uses. ( A pH range of 6.5 to 8.5 units applies to "all other waters.") Listing Policy section 3.10 contains directions for assessment based on trends in water quality. Though the LOE (33846) associated with this decision finds that 24 of the 970 samples exceed the water quality objective, this can not be determined with certainty because baseline conditions (normal ambient pH) has not been established for this waterbody. As such, it is more accurate to report the use rating for this decision as insufficient information not fully supporting. Staff recommend some trend analysis be completed on this data set before next listing cycle to determine the normal ambient pH for this waterbody. 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 It can not be determined with certainty if 24 of the 970 samples exceed the water quality objective because the water quality objective requires that a normal ambient pH be established for this waterbody in order to determine protection of the COLD beneficial use. 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 161941, pH	Region 6
Indian Creek (Alpine County)

LOE ID:

341697

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 EPA National Aquatic Resources Survey (NARS) data for Indian Creek (Alpine County) to determine beneficial use support and results are as follows: 0 of 1 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:

WQX from the NWQMP 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP

Line of Evidence (LOE) for Decision ID 161941, pH	Region 6
Indian Creek (Alpine County)

LOE ID:

33846

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

970

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Numeric data generated from 970 minimums and maximums of pH data had 24 exceedences.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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. 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. [There is no site specific objective for pH for this water body]

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the following stations: SW-02, SW-03, SW-04, and SW-10.

Temporal Representation:

Samples were collected once a month from July 1980 to June 2010.

Environmental Conditions:

QAPP Information:

SWAMP QAPP

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan

Line of Evidence (LOE) for Decision ID 161941, pH	Region 6
Indian Creek (Alpine County)

LOE ID:

341678

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:

WQX from the NWQMP 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: NARS_WQX-NRS_CA-11354 (Indian Creek).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Generic SWAMP QAPrP


DECISION ID	69137	Region 6
Indian Creek (Alpine County)

Pollutant:	Habitat alterations
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	Regional Board conclusion: This pollutant was considered for removal 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: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of removing this water segment-pollutant combination from the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that the original listing basis was faulty due to the fact that the listing was not for a pollutant.

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 69137, Habitat alterations	Region 6
Indian Creek (Alpine County)

LOE ID:

2863

Pollutant:

Habitat alterations

LOE Subgroup:

Testimonial Evidence

Matrix:

Not Specified

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 habitat listing was based on best professional judgment (Department of Fish and Game staff in the 1980s pointed out riparian damage in West Fork Carson River watershed during field trip).

Habitat alteration is not for a pollutant; therefore, the habitat alteration listing will be removed.

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):


DECISION ID	79179	Region 6
Indian Creek (Alpine County)

Pollutant:	Boron
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:	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. One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds 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 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. The single sample did not exceed the objective and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of 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:	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 79179, Boron	Region 6
Indian Creek (Alpine County)

LOE ID:

34603

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total 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 sample collected did not exceed the evaluation guideline of 1000 ug/L.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Lahontan Region Basin Plan (2011): Waters 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 the following provisions of Title 22 of the California Code of Regulations which are incorporated by reference into this plan: Table 64431-A of Section 64431 (Inorganic Chemicals), Table 64431-B of Section 64431 (Fluoride), Table 64444-A of Section 64444 (Organic Chemicals), Table 64449-A of Section 64449 (Secondary Maximum Contaminant LevelsConsumer Acceptance Limits), and Table 64449-B of Section 64449 (Secondary Maximum Contaminant Levels-Ranges).

Objective/Criterion Reference:

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

Evaluation Guideline:

Notification levels (formerly called "action levels")are published by the California Department of Public Health (CDPH) for chemicals for which there is no drinking water MCL. Notification levels are based mainly on health effects -- in most cases an incremental cancer risk estimate of 10(-6) for carcinogens and a threshold toxicity limit for other constituents. As with MCLs, the ability to quantify the amount of the constituent in a water sample using readily available analytical methods may cause notification levels to be set at somewhat higher concentrations than purely health-based values. Notification levels are advisory to water suppliers. If a notification level is exceeded, local government notification is required and customer notification is recommended. At a higher level, called the response level, the drinking water source is recommended to be taken out of service. The criteria for boron is 1000 ug/L (1 mg/L).

Guideline Reference:

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

Spatial Representation:

One sample was collected from the L-1 station.

Temporal Representation:

One sample was collected on 7/30/2002.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):


DECISION ID	79130	Region 6
Indian Creek (Alpine County)

Pollutant:	Temperature, water
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:	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. One line of evidence is available in the administrative record to assess this pollutant. Seven of the 944 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 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. Seven of 944 samples exceeded 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:	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 79130, Temperature, water	Region 6
Indian Creek (Alpine County)

LOE ID:

31705

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

944

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Seven of the 944 samples exceeded the evaluation guideline for temperature in this water body.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit above or below the natural temperature. For waters designated COLD, the temperature shall not be altered.

Objective/Criterion Reference:

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

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Fish introductions in CA: History and impact on native fishes. Davis, CA: University of CA, Davis

Spatial Representation:

Samples were collected at the following locations in this water body: Indian Creek @ Diversion Indian Creek downstream of 1st bridge Indian Creek upstream of 2nd bridge Indian Creek @ Springmeyer Ranch

Temporal Representation:

Samples collected between 7/8/1980 and 6/2/2010.

Environmental Conditions:

QAPP Information:

South Tahoe Public Utility District Laboratory Quality Assurance Program by Terry Powers, Laboratory Director (March 30, 2009)

QAPP Information Reference(s):


DECISION ID	79705	Region 6
Indian Creek (Alpine County)

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Sources:	A Source Unknown
TMDL Priority:	Medium
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. One line of evidence is available in the administrative record to assess this pollutant. 571 of the 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 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. 571 of 824 samples exceed the 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:	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 79705, Oxygen, Dissolved	Region 6
Indian Creek (Alpine County)

LOE ID:

34074

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

824

Number of Exceedances:

571

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Numeric data generated from 824 computed averages of Dissolved Oxygen data yielded 571 exceedences.

Data Reference:

Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010

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. COLD/SPAWN: 7-Day Mean: 9.5 mg/L

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the SW-02, SW-03, SW-04, and SW-10 stations.

Temporal Representation:

Samples were collected approximately twice a month from July 1980 to June 2010 and consequently consolidated into monthly samples.

Environmental Conditions:

QAPP Information:

Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.

QAPP Information Reference(s):