The MSAR TMDL Task Force was formed to implement TMDLs adopted by the Santa Ana Regional Water Quality Control Board to address exceedences of the fecal coliform objective established to protect the REC-1 use for waterbodies located within the Middle Santa Ana River Watershed. The Task Force is represented by a number of key watershed stakeholders including the Santa Ana Regional Water Quality Control Board
Various waterbodies in the Middle Santa Ana River (MSAR) watershed are listed on the state 303(d) list of impaired waters due to high densities of fecal coliform bacterial indicators. These waterbodies are: the Santa Ana River, Reach 3; Chino Creek, Reaches 1 and 2; Cucamonga Creek, Reach 1, Mill Creek (Prado Area); and, Prado Park Lake.
The Santa Ana Regional Water Quality Control Board adopted a Total Maximum Daily Load (TMDL) for fecal coliform bacterial indicators in December 2004. The TMDL became effective when the United States Environmental Protection Agency (EPA) gave it final approval on May 16, 2007. The scientific data and analysis used to justify the TMDL is summarized in a detailed technical support document prepared by the Regional Board staff.
The MSAR Bacterial Indicator TMDL established wasteload allocations for urban MS4 and confined animal feeding operation discharges and load allocations for agricultural and natural sources. The wasteload and load allocations were established for both fecal coliform and E. coli:
- Fecal coliform: 5-sample/30-day logarithmic mean (or geometric mean) less than 180 organisms/ 100 mL and not more than 10 percent of the samples exceed 360 organisms/100 mL for any 30-day period.
- coli: 5-sample/30-day logarithmic mean (or geometric mean) less than 113 organisms/100 mL and not more than 10 percent of the samples exceed 212 organisms/100 mL for any 30-day period.
The TMDL includes a detailed Implementation Plan which describes a variety of activities that must be undertaken to meet water quality standards for the various waterbodies in the Middle Santa Ana River Watershed. In the decade following EPA’s approval, stakeholders throughout the watershed initiated a large number of programs and projects to comply with the requirements set forth in the TMDL Implementation Plan.
Copies of Santa Ana Regional Water Quality Control Board Resolution No. R8-2005-0001 and TMDL Technical Document prepared by Board staff , as well as, deliverables submitted to the Board by Task Force stakeholders are available on the Regional Board Middle Santa Ana River TMDL webpage.
