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

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name: Twain Harte Creek (Tuolumne County)
Water Body ID: CAR5363101020101020200841
Water Body Type: River & Stream
 
DECISION ID
127013
Region 5     
Twain Harte Creek (Tuolumne County)
 
Pollutant: Indicator Bacteria
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: A Source Unknown | Grazing-Related Sources | Natural Sources
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section 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 for Water Contact Recreation (REC-1). Five of the thirteen samples, expressed as a Statistical Threshold Value, exceed the objective for REC-1.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from 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 thirteen samples, expressed as a Statistical Threshold Value, exceed the objective for REC-1 and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is equal to or less than 1 part per thousand 95 percent or more of the time, the E. coli bacteria objective applies Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the E. Coli objective.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

For E. Coli data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody.

No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.
 
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: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is equal to or less than 1 part per thousand 95 percent or more of the time, the E. coli bacteria objective applies Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the E. Coli objective.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

For E. Coli data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody.

No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.
 
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 127013, Indicator Bacteria
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70819
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 3 samples exceeded the E. coli geomean objective.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Central Valley Region, Sacramento River and San Joaquin River Basins)
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline: The geometric mean for E. coli in freshwater is 126 MPN/100mL. USEPA Ambient Water Quality Criteria for Bacteria -1986.
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: The samples were collected from Twain Harte Creek in the town of Twain Harte. Th sample site is adjacent to Eproson Park. CAR5363101020101020200841
Temporal Representation: Samples were collected approximately weekly during the month of March in 2010.
Environmental Conditions:
QAPP Information: Samples were collected under the Quality Assurance Project Plan for Tuolumne County Water Quality Project, version 1.0.
QAPP Information Reference(s): Quality Assurance Project Plan for Tuolumne County Water Quality Project, versioin 1.0.
 
Line of Evidence (LOE) for Decision ID 127013, Indicator Bacteria
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70821
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 6
Number of Exceedances: 2
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Two of the 6 samples exceeded the e. coli objective.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Central Valley Region, Sacramento River and San Joaquin River Basins)
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL. USEPA Ambient Water Quality Criteria for Bacteria -1986.
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: The samples were collected from Twain Harte Creek in the town of Twain Harte. Th sample site is adjacent to Eproson Park. CAR5363101020101020200841
Temporal Representation: Samples were collected approximately weekly during the month of March in 2010.
Environmental Conditions:
QAPP Information: Samples were collected under the Quality Assurance Project Plan for Tuolumne County Water Quality Project, version 1.0.
QAPP Information Reference(s): Quality Assurance Project Plan for Tuolumne County Water Quality Project, versioin 1.0.
 
Line of Evidence (LOE) for Decision ID 127013, Indicator Bacteria
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70820
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 14
Number of Exceedances: 5
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Five of the 14 samples exceeded the E. coli objective.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Central Valley Region, Sacramento River and San Joaquin River Basins)
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline: The E. coli concentration shall not exceed more than 235/100 ml. USEPA Ambient Water Quality Criteria for Bacteria - 1986.
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: The samples were collected at Twain Harte Creek at Crystal Falls Drive and Twain Harte Creek at Eproson Park. WBID: CAR5363101020101020200841
Temporal Representation: The samples were collected once a month from November 2008 to June 2009.
Environmental Conditions:
QAPP Information: This data was collected under the QAPP for Tuolumne County Water Quality Plan and Water-Quality Monitoring Field Procedures Manual, Tuolumne County Stream Team.
QAPP Information Reference(s): Quality Assurance Project Plan for Tuolumne County Water Quality Project, versioin 1.0.
 
Line of Evidence (LOE) for Decision ID 127013, Indicator Bacteria
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 194446
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 13
Number of Exceedances: 5
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Twain Harte Creek (Tuolumne County) to determine beneficial use support and the results are as follows: 5 of the 13 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water data for the 2020/2022 integrated report in Region 5.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): THC
Temporal Representation: The samples were collected between the days of 2018-01-15 and 2019-05-06 .
Environmental Conditions:
QAPP Information: Central Sierra Environmental Resource Center. 2018. Surface Water Ambient Monitoring Project in the Merced, Mokelumne, Stanislaus and Tuolumne River Watersheds.
QAPP Information Reference(s): Surface Water Ambient Monitoring Project in the Merced, Mokelumne, Stanislaus and Tuolumne River Watersheds
 
 
DECISION ID
91666
Region 5     
Twain Harte Creek (Tuolumne County)
 
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)(2016)
Revision Status Original
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.

One line of evidence is available in the administrative record to assess this pollutant. Two of the 29 samples exceed the Criteria/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 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. Two of 29 samples exceeded the Criteria/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: 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 91666, Oxygen, Dissolved
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70841
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 29
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two of the 29 samples exceeded the objective.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentrations shall not be reduced below the following minimum levels at any time: Waters designated COLD: 7.0 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the Twain Harte Creek at Crystal Falls Dr. and Twain Harte Creek at Eproson Park stations.
Temporal Representation: Samples were collected approximately once a month from November 2007 to December 2009.
Environmental Conditions:
QAPP Information: QUALITY ASSURANCE PROJECT PLAN TUOLUMNE COUNTY WATER QUALITY PLAN PROJECT Final Version 1.0 Prepared for Tuolumne County By Environmental Science Associates (September 21, 2005)
QAPP Information Reference(s):
 
 
DECISION ID
91723
Region 5     
Twain Harte Creek (Tuolumne County)
 
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)(2016)
Revision Status Original
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.

One line of evidence is available in the administrative record to assess this pollutant. Zero of the seven samples exceed the Criteria/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 seven samples exceeded Criteria/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 26 samples is needed to determine if a beneficial use is fully supported using table 3.2.
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 91723, Specific Conductivity
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70843
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 7
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: None of the 7 samples exceeded 900 uS/cm.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The secondary MCLs for electrical conductivity provide a range of values including a recommended level (900 uS/cm), upper level (1600 uS/cm) and a short-term level (2200 uS/cm). The 'recommended' level of 900 uS/cm was used as it is intended to be protective of all drinking water uses.
Objective/Criterion Reference: Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples collected on creek in town of Twain Hart, Twain Harte Creek (tributary of Tuolumne River via Sullivan Creek).
Temporal Representation: Sample collected on monthly between November 2008 to May 2009.
Environmental Conditions:
QAPP Information: Data QA well documented in data submittal.
QAPP Information Reference(s):
 
 
DECISION ID
91724
Region 5     
Twain Harte Creek (Tuolumne 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 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.

One line of evidence is available in the administrative record to assess this pollutant. Zero of the 32 samples exceed the Evaluation 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 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 32 samples exceeded the Evaluation 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: 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 91724, Temperature, water
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70844
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 32
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data provided by CSERC (Tuolumne County Stream Team). None of the 32 samples exceeded the evaluation guideline for temperature in this water body.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Water Board that such alteration in temperature does not adversely affect beneficial uses. In determining compliance with the water quality objectives for temperature, appropriate averaging periods may be applied provided that beneficial uses will be fully protected (Central Valley Regional Board Basin Plan, Pg. III-8.00, Water Quality Objectives).
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
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: Inland Fishes of California (1976)
 
Spatial Representation: Samples were collected in Twain Harte Creek at Crystal Falls Dr. and in Twain Harte Creek at Eproson Park.
Temporal Representation: Samples were collected monthly from 11/2007-6/2008 and 1/2009-6/2009.
Environmental Conditions:
QAPP Information: QUALITY ASSURANCE PROJECT PLAN TUOLUMNE COUNTY WATER QUALITY PLAN PROJECT Final Version 1.0 Prepared for Tuolumne County By Environmental Science Associates (September 21, 2005)
QAPP Information Reference(s):
 
 
DECISION ID
91837
Region 5     
Twain Harte Creek (Tuolumne County)
 
Pollutant: Trash
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 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.

One line of evidence is available in the administrative record to assess this pollutant. Zero of the zero samples exceed the Criteria/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 zero samples exceeded Criteria/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 26 samples is needed to determine if a beneficial use is fully supported using table 3.2.
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 91837, Trash
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 59484
 
Pollutant: Trash
LOE Subgroup: Pollutant-Nuisance
Matrix: -N/A
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Occurrence of conditions judged to cause impairment
Data Used to Assess Water Quality: During multiple dates in 2007, 2008, and 2009, the Tuolumne County Stream Team observed trash, foam, suds, and an oily sheen.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: From the Region 5 Basin Plan: Water shall not contain floating material in amounts that cause nuisance or adversely affect beneficial uses. Waters shall not contain oils, greases, waxes, or other materials in concentrations that cause nuisance, result in a visible film or coating on the surface of the water or on objects in the water, or otherwise adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Twain Harte Creek at Eproson Park, and Twain Harte Creek at Crystal Falls Drive.
Temporal Representation: Numerous dates in 2007, 2008, and in 2009.
Environmental Conditions:
QAPP Information: Tuolumne County Water Quality Plan Project QAPP, dated Sept. 2005 was provided.
QAPP Information Reference(s): Quality Assurance Project Plan for Tuolumne County Water Quality Project, versioin 1.0.
 
 
DECISION ID
82499
Region 5     
Twain Harte Creek (Tuolumne County)
 
Pollutant: pH
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
Expected TMDL Completion Date: 2027
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.

One line of evidence is available in the administrative record to assess this pollutant. Five of the 30 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 30 samples exceed the water quality objectives 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: 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 82499, pH
Region 5     
Twain Harte Creek (Tuolumne County)
 
LOE ID: 70842
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 30
Number of Exceedances: 5
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Numeric data generated from 30 minimums and maximums of pH data had 5 exceedences.
Data Reference: Data for Tuolumne County Stream Team Water Quality Monitoring Report, 2007-2009.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH of all inland surface waters shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from the Twain Harte Creek at Crystal Falls Dr. and Twain Harte Creek at Eproson Park stations.
Temporal Representation: Samples were collected approximately once a month from November 2007 to June 2008 and December 2008 to May 2009.
Environmental Conditions:
QAPP Information: NPDES data quality assurance.
QAPP Information Reference(s):