Cal. Code Regs. tit. 23 § 3969.6
On May 10, 2022, the Colorado River Basin Regional Water Quality Control Board (Colorado River Basin Water Board) adopted Resolution No. R7-2022-0032, amending the Water Quality Control Plan for the Colorado River Basin Region to establish a Total Maximum Daily Load (TMDL) for organophosphate (OP) and organochlorine (OC) compounds in Imperial Valley surface waters (Basin Plan Amendment). On November 15, 2022, the Basin Plan Amendment was approved by the State Water Resources Control Board (State Water Board) per Resolution No. 2022-0046.
The surface waters in the Imperial Valley, including Alamo River, Imperial Valley Drains, New River and Wiest Lake, are polluted/impaired by certain organophosphate (OP) and/or organochlorine (OC) compounds that are toxic to humans and aquatic life. Sources of OP and OC compounds are primarily from irrigated agricultural lands based upon pesticide use restrictions, the uses of the compounds, the amount of land used for agricultural purposes, and water quality data. Discharges from irrigated agricultural lands are considered nonpoint source discharges.
The TMDL in the Basin Plan Amendment sets numeric targets, waste load allocations, load allocations, and implementation plans to control discharges of OP and OC compounds to Imperial Valley surface waters. The Implementation Plan set forth in Waste Discharge Requirements Order R7-2021-0050 (General Waste Discharge Requirements for Discharges of Waste from Irrigated Lands for Dischargers that are Members of a Coalition Group in the Imperial Valley) (Imperial Valley Agricultural Order) and its associated Monitoring and Reporting Program (MRP) will provide the information to confirm that the TMDL is being implemented, and numeric targets and allocations will be achieved.
Cal. Code Regs. Tit. 23, § 3969.6