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Pollutant: <br />Indicator Bacteria <br />Final Listing Decision: <br />List on 303(d) list (TMDL required list) <br />Last Listing Cycle's Final New Decision <br />Listing Decision: <br />Revision Status <br />Revised <br />Sources: <br />Source Unknown <br />Expected TMDL <br />2021 <br />Completion Date: <br />Impairmentfrom <br />Pollutant <br />Pollutant or Pollution: <br />Regional Board USEPA Final Approval Decision Details: <br />Conclusion: <br />The November 12, 2010 USEPA partial approval letter and the October 11, 2011 <br />final approval letter both from Alexis Strauss, USEPA Region 9, to Tom Howard, <br />SWRCB, concluded the following: <br />USEPA added Santa Ana River, Reach 2 to the list of water quality limited <br />segments requiring a TMDL for indicator bacteria. This water body is designated as <br />a Water Contact Recreation (REC1) water body either explicitly or implicitly as <br />tributaries to other designated segments (RWQCB Santa Ana Region, 2008, Table <br />3-1, pp.3-23 - 3-35). <br />The Santa Ana Basin Plan has the following water quality objective for fecal <br />coliform to protect REC1 beneficial use: <br />Fecal coliform: log mean less than 200 organisms/100 mL based on five or more <br />samples/30 day period, and not more than 10% of the samples exceed 400 <br />organisms/100 mL for any 30-day period. (RWQCB Santa Ana Region, 2008, pp.4- <br />9) <br />Recent monitoring data collected in this water body measures Escherichia coli (E. <br />coli) indicator bacteria. E. coli is one species within the broader category of fecal <br />coliform bacteria and monitoring data for E. coli can be used to evaluate whether <br />the fecal coliform objective is being met in the subject water body. In addition, <br />USEPA has recommended that California use USEPA's Ambient Water Quality <br />Criteria for Bacteria (1986) when there is no adopted E. coli standard. Specifically, <br />USEPA recommends that for REC1 beneficial use the following criteria be used: <br />Steady state geometric mean indicator density - 126 indicator densities/100ml <br />Designated beach area (upper 75% confidence limit) - 235 indicator <br />densities/100ml (EPA, 1986, Table 4, pp.15) <br />USEPA compared the E. coli data for subject water bodies to the Basin Plan's fecal <br />coliform objective, as well as to USEPA's recommended E. coli criteria and the <br />results were: <br />1. Thirty-seven of the 150 samples taken exceeded the USEPA E. coli criteria (235 <br />organ isms/100m 1). <br />2. Twenty-seven of the 150 samples taken exceeded the Basin Plan objective for <br />fecal coliform (400 organism s/100m1). <br />For this water body segment, sufficient exceedances of the fecal coliform objective <br />and the USEPA recommended criteria exist to merit listings per the 10% <br />exceedance threshold for conventional pollutants expressed in Table 3.2 of the <br />State Listing Policy. <br />For historical clarification, the Regional and State Water Board detailed decision <br />recommendations made prior to USEPA's final decision are presented in their <br />