Draft 2008 California 303(d)/305(b) Integrated Report

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Big Meadow Creek
Water Body ID: CAR6341001120011213123239
Water Body Type: River & Stream
 
DECISION ID
6275
 
Pollutant: Pathogens
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Revised
Reason for Delisting: State determines water quality standard is being met
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: Big Meadow Creek was originally listed for "Pathogens" on the basis of data for
fecal coliform bacteria.

This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Twenty-one rolling average datapoints exceeded the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the section 303(d) list.

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. Twenty-one of 197 datapoints exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation: N/A
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 6275
 
LOE ID: 26293
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 128
Number of Exceedances: 16
 
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 U.S. Forest Service and Lahontan RWQCB staff in 2000, 2001, 2002 and 2008. It focuses on violations of the 20/100 mL limit Data were evaluated as 30-day normalized log means. For the four years of sampling there were 128 log mean datapoints and 16 datapoints in violation of the 20/100 mL limit.
Data Reference: 2008. Big Meadow Post Grazing Allotment Violation Analysis.
  2009. Determination of Fecal Coliform Violations of Lahontan Basin Plan Water Quality Objectives: Data Reduction Procedure
 
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).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data were collected at three stations at the lower boundary of the former grazing allotment, in the middle of the allotment, and in the upper portion of the allotment. Station BM1 is at the bridge; Station BM2 is at "photo op Station 18," and Station BM3 is below the beaver dam at the upper meadow.
Temporal Representation: The data used were collected in 2000, 2001, 2002 and 2008. Two to five samples were collected in each 30-day period. Samples were collected approximately weekly during the former grazing season.. In 2008 samples were collected approximately weekly between mid-July and December, with the exception that no samples were collected in October.
Environmental Conditions: Big Meadow Creek is a tributary of the Upper Truckee River in the Lake Tahoe Basin. Its watershed 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):