Final California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 7 - Colorado River Basin Region

Water Body Name: Horsethief Creek
Water Body ID: CAR7194700020171212032479
Water Body Type: River & Stream
 
DECISION ID
101409
Region 7     
Horsethief Creek
 
Pollutant: Aluminum
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard.

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 one sample(s) exceed the water quality standard and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101409, Aluminum
Region 7     
Horsethief Creek
 
LOE ID: 127009
 
Pollutant: Aluminum
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Aluminum.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for aluminum is 0.2 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101420
Region 7     
Horsethief Creek
 
Pollutant: Ammonia
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of two sample(s) exceed the water quality standard for each of the two beneficial uses.

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 two sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101420, Ammonia
Region 7     
Horsethief Creek
 
LOE ID: 127556
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as \the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.\""
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2014-04-15 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101420, Ammonia
Region 7     
Horsethief Creek
 
LOE ID: 127557
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Ammonia as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference: Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2014-04-15 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101410
Region 7     
Horsethief Creek
 
Pollutant: Arsenic
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101410, Arsenic
Region 7     
Horsethief Creek
 
LOE ID: 128656
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101410, Arsenic
Region 7     
Horsethief Creek
 
LOE ID: 128657
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Arsenic.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
103780
Region 7     
Horsethief Creek
 
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 is being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, an additional line of evidence associating the Benthic Community Effects with a water or sediment concentration of pollutants is necessary to assess listing status. One line of evidence is available in the administrative record to assess this indicator. The three California Stream Condition Index (CSCI) scores meets the water quality objective. Additionally, this water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI. Available data show that there are no other pollutants that are causing impairment in this water body.

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 water segment on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. The three CSCI scores meets the water quality objective, this water body passed several screening criteria and was identified as a reference water body, and available data show that there are no other pollutants that are causing impairment in this water body at this time.
 
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.
 
 
Line of Evidence (LOE) for Decision ID 103780, Benthic Community Effects
Region 7     
Horsethief Creek
 
LOE ID: 96518
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: The CSCI scores from this water body were:
0.882760163
0.950942355
0.896813406 (averaged from scores of two samples taken on the same day at the same location)

These three scores meets the water quality objective. Additionally, this water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
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: Samples collected from station 719HOTCPF
Temporal Representation: Samples collected on:
5/14/2013
4/15/2014
4/9/2015
Environmental Conditions:
QAPP Information: QAPP for SWAMP RWB7 Monitoring
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101411
Region 7     
Horsethief Creek
 
Pollutant: Cadmium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101411, Cadmium
Region 7     
Horsethief Creek
 
LOE ID: 127091
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Cadmium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101411, Cadmium
Region 7     
Horsethief Creek
 
LOE ID: 127092
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Cadmium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Maximum Contaminant Level for cadmium in the Basin Plan is 0.005 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101412
Region 7     
Horsethief Creek
 
Pollutant: Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the two samples exceed the guideline for each of the two beneficial uses.

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 two samples exceeded the guideline for each of the two beneficial uses 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.
 
 
Line of Evidence (LOE) for Decision ID 101412, Chloride
Region 7     
Horsethief Creek
 
LOE ID: 129024
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Chloride.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used: 500 mg/l Chloride (CCR, title 22).
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2014-04-15 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101412, Chloride
Region 7     
Horsethief Creek
 
LOE ID: 129025
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Chloride.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2014-04-15 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101413
Region 7     
Horsethief Creek
 
Pollutant: Chromium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101413, Chromium
Region 7     
Horsethief Creek
 
LOE ID: 127593
 
Pollutant: Chromium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chromium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101413, Chromium
Region 7     
Horsethief Creek
 
LOE ID: 128714
 
Pollutant: Chromium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chromium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for total chromium is 0.05 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101414
Region 7     
Horsethief Creek
 
Pollutant: Copper
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101414, Copper
Region 7     
Horsethief Creek
 
LOE ID: 127118
 
Pollutant: Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Copper.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for copper is 1.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101414, Copper
Region 7     
Horsethief Creek
 
LOE ID: 127119
 
Pollutant: Copper
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Copper.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101415
Region 7     
Horsethief Creek
 
Pollutant: Fluoride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. One of one sample(s) exceed the water quality standard.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. One of one sample(s) exceed the water quality standard and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101415, Fluoride
Region 7     
Horsethief Creek
 
LOE ID: 128829
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality standard for Fluoride.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Primary Maximum Contaminant Level (MCL) for Fluoride, is 2 mg/l.
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101434
Region 7     
Horsethief Creek
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3, 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 one sample(s) exceed the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the one sample(s) exceed the guideline 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.
 
 
Line of Evidence (LOE) for Decision ID 101434, Indicator Bacteria
Region 7     
Horsethief Creek
 
LOE ID: 126147
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a 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): 719HOTCPF
Temporal Representation: The samples were collected between the days of 2013-05-14 and 2013-05-14 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101416
Region 7     
Horsethief Creek
 
Pollutant: Lead
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101416, Lead
Region 7     
Horsethief Creek
 
LOE ID: 126905
 
Pollutant: Lead
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Lead.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Maximum Contaminant Level for lead in the Basin Plan is 0.015 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101416, Lead
Region 7     
Horsethief Creek
 
LOE ID: 126904
 
Pollutant: Lead
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Lead.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101417
Region 7     
Horsethief Creek
 
Pollutant: Manganese
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard.

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 one sample(s) exceed the water quality standard and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101417, Manganese
Region 7     
Horsethief Creek
 
LOE ID: 128639
 
Pollutant: Manganese
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Manganese.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for manganese is 0.5 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101418
Region 7     
Horsethief Creek
 
Pollutant: Nickel
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101418, Nickel
Region 7     
Horsethief Creek
 
LOE ID: 127668
 
Pollutant: Nickel
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Nickel.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nickel is 0.1 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101418, Nickel
Region 7     
Horsethief Creek
 
LOE ID: 127666
 
Pollutant: Nickel
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Nickel.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101419
Region 7     
Horsethief Creek
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Zero of two sample(s) exceed the water quality standard.

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 two sample(s) exceed the water quality standard and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101419, Nitrate/Nitrite (Nitrite + Nitrate as N)
Region 7     
Horsethief Creek
 
LOE ID: 128840
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Nitrate + Nitrite as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate + nitrite (as N) is 10.0 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2014-04-15 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101421
Region 7     
Horsethief Creek
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 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 three sample(s) exceed the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the three sample(s) exceed the guideline. 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.
 
 
Line of Evidence (LOE) for Decision ID 101421, Oxygen, Dissolved
Region 7     
Horsethief Creek
 
LOE ID: 128165
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Colorado River Basin, WARM Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101422
Region 7     
Horsethief Creek
 
Pollutant: Selenium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101422, Selenium
Region 7     
Horsethief Creek
 
LOE ID: 129011
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Selenium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Maximum Contaminant Level for selenium in the Basin Plan is 0.05 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101422, Selenium
Region 7     
Horsethief Creek
 
LOE ID: 128235
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Selenium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101423
Region 7     
Horsethief Creek
 
Pollutant: Silver
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101423, Silver
Region 7     
Horsethief Creek
 
LOE ID: 127531
 
Pollutant: Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Silver.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion maximum concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101423, Silver
Region 7     
Horsethief Creek
 
LOE ID: 127530
 
Pollutant: Silver
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Silver.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for silver is 0.1 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101425
Region 7     
Horsethief Creek
 
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: 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 three sample(s) exceed the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the three sample(s) exceed the guideline. 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.
 
 
Line of Evidence (LOE) for Decision ID 101425, Specific Conductivity
Region 7     
Horsethief Creek
 
LOE ID: 127007
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for SpecificConductivity.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for specific conductance is 900 uS/cm (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101427
Region 7     
Horsethief Creek
 
Pollutant: Total Dissolved Solids
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 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 one sample(s) exceed the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the one sample(s) exceed the guideline. 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.
 
 
Line of Evidence (LOE) for Decision ID 101427, Total Dissolved Solids
Region 7     
Horsethief Creek
 
LOE ID: 128457
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Total Dissolved Solids.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: California Secondary Maximum Contaminant Levels (MCLs) for consumer acceptance objective for total dissolved solids is 500 mg/L.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101428
Region 7     
Horsethief Creek
 
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: 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 three sample(s) exceed the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of three sample(s) exceeded the guideline 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.
 
 
Line of Evidence (LOE) for Decision ID 101428, Turbidity
Region 7     
Horsethief Creek
 
LOE ID: 127917
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Turbidity.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the 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(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101430
Region 7     
Horsethief Creek
 
Pollutant: Zinc
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of one sample(s) exceed the water quality standard for each of the two beneficial uses.

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 one sample(s) exceed the water quality standard for each of the two beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101430, Zinc
Region 7     
Horsethief Creek
 
LOE ID: 127950
 
Pollutant: Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Zinc.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101430, Zinc
Region 7     
Horsethief Creek
 
LOE ID: 127949
 
Pollutant: Zinc
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Zinc.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline: The California Secondary MCL for zinc is 5.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference: Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2013-05-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101432
Region 7     
Horsethief Creek
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2, a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. Zero of the three samples exceed the objective for each of the five beneficial uses.

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 three samples exceeded the objective for each of the five beneficial uses, 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.
 
 
Line of Evidence (LOE) for Decision ID 101432, pH
Region 7     
Horsethief Creek
 
LOE ID: 127704
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101432, pH
Region 7     
Horsethief Creek
 
LOE ID: 127705
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Freshwater Replenishment
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101432, pH
Region 7     
Horsethief Creek
 
LOE ID: 127702
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101432, pH
Region 7     
Horsethief Creek
 
LOE ID: 128644
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 101432, pH
Region 7     
Horsethief Creek
 
LOE ID: 127703
 
Pollutant: pH
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: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB7 Monitoring data for Horsethief Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference: Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (719HOTCPF)
Temporal Representation: The samples were collected between the dates of 2013-05-14 and 2015-04-09
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program