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LOE ID: |
27159 |
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Pollutant: |
Fecal Coliform |
LOE Subgroup: |
Pollutant-Water |
Matrix: |
Water |
Fraction: |
None |
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Beneficial Use: |
Water Contact Recreation |
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Number of Samples: |
103 |
Number of Exceedances: |
3 |
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Data and Information Type: |
Water column surveys (e.g. fecal coliform) |
Data Used to Assess Water Quality: |
This assessment uses data collected and analyzed by Lahontan RWQCB staff in 2000, 2001, 2002, 2003, 2004 and 2008. It focuses on violations of the 20/100 mL limit. Data were evaluated as 30-day normalized log means. For the six years of sampling there were 103 log mean datapoints and 3 datapoints in violation of the 20/100 mL limit. |
Data Reference: |
2008. Big Meadow Post Grazing Allotment Violation Analysis. |
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2008. Non-Point Source (NPS) Fecal Coliform (colonies/100 ml) for Upper Truckee River above Christmas Valley. |
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2009. Determination of Fecal Coliform Violations of Lahontan Basin Plan Water Quality Objectives: Data Reduction Procedure |
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Water Quality Objective/Criterion: |
The Lahontan Basin Plan's objective for coliform bacteria states:
"Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste.
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. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected." |
Objective/Criterion Reference: |
2007. Water Quality Control Plan for the Lahontan Region (as amended). |
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Evaluation Guideline: |
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Guideline Reference: |
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Spatial Representation: |
Data were collected at the Hawley Grade station at the bridge downstream of the USGS gage. |
Temporal Representation: |
The data used were collected in 2000, 2001, 2002, 2003, 2004 and 2008. |
Environmental Conditions: |
The Upper Truckee River is the largest tributary of Lake Tahoe. Its watershed above Christmas Valley is National Forest land and includes a popular hiking/mountain biking/cross country skiing trail. Range livestock grazing under a U.S. Forest Service permit occurred in the watershed prior to 2000. The permit was subsequently revoked. |
QAPP Information: |
The data were collected and analyzed using the Lahontan RWQCB's quality assurance protocols. |
QAPP Information Reference(s): |