Cal. Code Regs. tit. 23 § 3979.11
On August 4, 2017, the Santa Ana Regional Water Quality Control Board (Santa Ana Water Board) adopted Resolution No. R8-2017-0014, amending the Water Quality Control Plan for the Santa Ana River Basin to incorporate Total Maximum Daily Loads (TMDLs) for selenium in freshwater, Newport Bay watershed, Orange County, California (Basin Plan amendment). The State Water Resources Control Board (State Water Board) approved the Basin Plan amendment under Resolution No. 2018-0041 on September 20, 2018.
Resolution No. R8-2017-0014 establishes TMDLs for Selenium in three freshwater drainage systems in the Newport Bay watershed: Santa Ana-Delhi, San Diego Creek, and Big Canyon Wash subwatersheds. The TMDLs address exceedance of the California Toxics Rule (CTR) chronic water quality criterion for selenium and potential impairments to fish and birds via bioaccumulation in the freshwater portions of the watershed. Tissue-based targets for the protection of aquatic life (fish) and aquatic dependent wildlife (birds) are included in the TMDLs, as well as CTR-based water column targets. The objective of this amendment is to reduce levels of selenium in the watershed to protect water quality and potentially impaired beneficial uses.
The TMDL allocations are assigned to urban runoff, groundwater cleanup and dewatering dischargers and other National Pollutant Discharge Elimination System (NPDES) permittees, agriculture, open space, and rising groundwater. The allocations apply only during dry weather conditions (year-round) and are expressed as semiannual arithmetic means (April 1 through September 30 and October 1 through March 31).
The TMDLs provide compliance options, including best management practices (BMP) - based compliance, to be incorporated into relevant NPDES permits. The compliance options are included as part of the assumptions and requirements of these selenium TMDLs. Compliance schedules are included that reflect the phased TMDL structure, the individual requirements for each Regulated Party, and the adaptive management process, including periodic reevaluations of the selenium TMDLs (e.g., TMDL re-openers). Final compliance with the TMDLs is to be achieved as soon as possible but no later than thirty years from the Reconsidered TMDL effective date. This timeframe considers the existing challenges and lack of available reasonably feasible treatment technologies/BMPs for selenium and therefore provides adequate but reasonable time to identify, design, and implement approaches in the future.
Cal. Code Regs. Tit. 23, § 3979.11