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

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name: Chicken Ranch Beach
Water Body ID: CAC2011403320070320160601
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
6420
 
Pollutant: Indicator Bacteria
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Sources: Source Unknown
Expected TMDL Completion Date: 2010
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: USEPA placed this water body-pollutant combination on the section 303(d) list using the data and information contained in the line of evidence.
 
RWQCB Board Decision / Staff Recommendation: No new data were assessed for 2008. The decision has not changed.
 
SWRCB Board Decision / Staff Recommendation: N/A
 
USEPA Decision: The USEPA final decision for the 2006 303(d) list was to list this water body segment for indicator bacteria.
 
 
Lines of Evidence (LOEs) for Decision ID 6420
 
LOE ID: 348
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 140
Number of Exceedances: 25
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Available data indicate sufficient exceedances of bacterial indicator objectives. There were 13 out of 139 samples that exceeded the single sample maximum for total coliform, 9 out of 140 that exceeded the single sample maximum for fecal coliform, 25 out of 140 that exceeded the single sample maximum for enterococci, and 20 out of 118 that exceeded the geomean for enterococci (USEPA, 2007).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: Title 17 C.C.R. Section 7958 states: Based on a single sample, the density of bacteria in water from each sampling station at a public beach or public water contact sports area shall not exceed:
(A) 1,000 total coliform bacteria per 100 milliliters, if the ratio of fecal/total coliform bacteria exceeds 0.1; or
(B) 10,000 total coliform bacteria per 100 milliliters; or
(C) 400 fecal coliform bacteria per 100 milliliters; or
(D) 104 enterococcus bacteria per 100 milliliters.

Based on the mean of the logarithms of the results of at least five weekly samples during any 30-day sampling period, the density of bacteria in water from any sampling station at a public beach or public water contact sports area, shall not exceed:
(A) 1,000 total coliform bacteria per 100 milliliters; or
(B) 200 fecal coliform bacteria per 100 milliliters; or
(C) 35 enterococcus bacteria per 100 milliliters. (DHS, 1999)
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation: 04/01/2003-10/25/2005
Environmental Conditions:
QAPP Information: Data record: summers 2003-2005, Marin County Health Dept.
QAPP Information Reference(s):