The Basin Plan amendment modifies the regulatory provisions of the Water Quality Control Plan for the Santa Ana Region by establishing Total Maximum Daily Loads (TMDLs) for bacterial indicators discharged to impaired water bodies in the Middle Santa Ana River watershed, including the Santa Ana River, Reach 3; Chino Creek, Reaches 1 and 2; Mill Creek (Prado Area); Cucamonga Creek (Valley Reach); and Prado Park Lake. The TMDLs address impairment due to bacterial indicators in the Middle Santa Ana River watershed in a prioritized phased approach. Compliance with objectives to protect water contact recreation are to be achieved no later than December 31, 2015 during the dry season and no later than December 31, 2025 during the wet season. Density-based allocations are assigned for urban discharges, agricultural discharges, and natural or open space discharges. These allocations are expected to be implemented through requirements imposed by the Santa Ana Regional Water Quality Control Board in waste discharge requirements and/or conditional waivers of waste discharge requirements. The TMDLs will be re-evaluated and revised, if appropriate, based on monitoring results and relevant studies required by the TMDL implementation plan. These studies include source evaluation and characterization, watershed-wide water quality monitoring, water contact recreation beneficial use assessments, and alternative bacterial indicator evaluations. Based on the results of these investigations, plans for achieving the TMDLs are to be developed by the stakeholders. Revision of the TMDLs would occur through the Basin Plan amendment process.
Cal. Code Regs. Tit. 23, § 3979.1