Cal. Code Regs. tit. 23 § 3969
Colorado River Basin Regional Water Quality Control Board (Regional Board) Resolution No. R7-2010-0011, adopted on May 20, 2010, by the Regional Board, modified the regulatory provisions of the Water Quality Control Plan for the Colorado River Basin Region (Basin Plan) by establishing a Total Maximum Daily Load (TMDL) and Implementation Plan for Dissolved Oxygen (DO) in the New River at the International Boundary (IB). The TMDL addresses DO impairment in the New River due to wastewater entering California at the IB with Mexico. The TMDL numeric target for DO is a minimum of 0.5 mg/L at any time and applies to the first 12-mile segment of the New River downstream from the IB. All publicly owned treatment works that discharge pollutants from point sources in the impaired New River have been issued NPDES permits, which prescribe TMDL allocations, as specified in the TMDL. The implementation plan consists of two phases. Phase 1 requests that U.S. Environmental Protection Agency (USEPA) and the U.S. Section of the International Boundary and Water Commission (USIBWC) report measures taken to ensure Mexico's compliance with the TMDL; continue to monitor water quality and DO in the New River at the IB; and submit monitoring and progress reports to the Regional Water Board staff according to the specified schedule. Phase 1 also requests that other cooperating agencies with interests in New River water quality sign a Memorandum of Understanding (MOU) to ensure coordination of IB projects. Phase 1 measures should be sufficient to achieve the New River DO water quality objectives (WQOs). Phase 1 will be implemented in the first 3 years after USEPA approves the TMDL. Phase 2 (the second 3 years after USEPA approval) will be implemented if Phase 1 does not result in attaining the DO WQO. Regional Water Board staff will track implementation and monitor water quality progress in both phases, and will propose modification of the TMDL to the Regional Water Board, if necessary, in phase 2.
Cal. Code Regs. Tit. 23, § 3969