| Water Body Name: | Cottonwood Creek (above LADWP diversion, Inyo County) |
| Water Body ID: | CAR6033015020070824171418 |
| Water Body Type: | River & Stream |
DECISION ID |
101956 |
Region 6 |
Cottonwood Creek (above LADWP diversion, Inyo County) |
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| 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 Staff Conclusion: | This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.
Four lines of evidence are available in the administrative record to assess this pollutant, with two lines of evidence assessing the same data for different versions of the Fecal coliform standard for MUN (i.e., log mean and 90th percentile) and two lines of evidence assessing the same data for different versions of the E. coli standard (i.e., geomean and statistical threshold value). Zero of the 12 samples exceed the REC1 E.coli objective and zero of 30 samples exceed the MUN Fecal coliform objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 12 samples exceed the REC1 E.coli objective and zero of 30 samples exceed the MUN Fecal coliform objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Staff 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. |
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| LOE ID: | 99916 | ||||
| Pollutant: | Escherichia coli (E. coli) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 12 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed RWB6_BACT_Monitoring data for Cottonwood Creek (above LADWP diversion, Inyo County) to determine beneficial use support and the results are as follows: 0 of the 12 samples exceeded the geomean water quality standard for E. coli. This is a six week rolling geomean that is calculated weekly. | ||||
| Data Reference: | Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring. | ||||
| SWAMP Data: | SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a six-week rolling GEOMETRIC MEAN (GM) of Escherichia coli (E. coli) not to exceed 100 colony forming units per 100 milliliters (cfu/100 mL) (calculated weekly). | ||||
| Objective/Criterion Reference: | Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | The samples were collected at 4 monitoring site(s), station(s): 603CTNB01, 603CTNB02, 603CTNB03, 603WGTB01 | ||||
| Temporal Representation: | The samples were collected between the days of 2011-07-10 and 2013-07-19 . | ||||
| 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 | ||||
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| LOE ID: | 100000 | ||||
| Pollutant: | Escherichia coli (E. coli) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 12 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed RWB6_BACT_Monitoring data for Cottonwood Creek (above LADWP diversion, Inyo County) to determine beneficial use support and the results are as follows: 0 of the 12 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring. | ||||
| SWAMP Data: | SWAMP | ||||
| Water Quality Objective/Criterion: | 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 4 monitoring site(s), station(s): 603CTNB01, 603CTNB02, 603CTNB03, 603WGTB01 | ||||
| Temporal Representation: | The samples were collected between the days of 2011-07-10 and 2013-07-19 . | ||||
| 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 | ||||
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| LOE ID: | 129339 | ||||
| Pollutant: | Fecal Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 30 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed RWB6_BACT_Monitoring data for Cottonwood Creek (above LADWP diversion, Inyo County) to determine beneficial use support and the results are as follows: 0 of the 30 samples exceeded the logmean water quality standard for Coliform, Fecal. This is a 30-day rolling logmean that is calculated daily. | ||||
| Data Reference: | Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring. | ||||
| SWAMP Data: | SWAMP | ||||
| Water Quality Objective/Criterion: | Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml. (Lahontan Region Basin Plan) | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | The samples were collected at 4 monitoring site(s), station(s): 603CTNB01, 603CTNB02, 603CTNB03, 603WGTB01 | ||||
| Temporal Representation: | The samples were collected between the days of 2011-07-10 and 2013-07-19 . | ||||
| 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 | ||||
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| LOE ID: | 129328 | ||||
| Pollutant: | Fecal Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 12 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed RWB6_BACT_Monitoring data for Cottonwood Creek (above LADWP diversion, Inyo County) to determine beneficial use support and the results are as follows: 0 of the 12 samples exceeded the water quality standard for Coliform, Fecal. The water quality standard is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring. | ||||
| SWAMP Data: | SWAMP | ||||
| Water Quality Objective/Criterion: | Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. (Lahontan Region Basin Plan) | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended) | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | The samples were collected at 4 monitoring site(s), station(s): 603CTNB01, 603CTNB02, 603CTNB03, 603WGTB01 | ||||
| Temporal Representation: | The samples were collected between the days of 2011-07-10 and 2013-07-19 . | ||||
| 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 | ||||