Cal. Code Regs. tit. 23 § 3939.6

Current through Register 2024 Notice Reg. No. 43, October 25, 2024

Section 3939.6 - A Total Maximum Daily Load for Nitrogen Compounds in the Santa Clara River

Los Angeles Regional Water Quality Control Board (Regional Board) Resolution No. 2003-011, adopted on August 7, 2003 by the Regional Board, modified the regulatory provisions of the Water Quality Control Plan for the Los Angeles Region (Basin Plan) by (1) revising the Table of Contents, (2) adding introductory text for Chapter 7 (Total Maximum Daily Loads), and (3) establishing a Total Maximum Daily Load (TMDL) for nitrogen compounds in the Santa Clara River. The TMDL specifies concentration-based targets for ammonia, nitrate, nitrite, and combined nitrate and nitrite. The TMDL includes a margin of safety with both implicit and explicit components.

Numeric targets will primarily be achieved by limiting the amount of nitrogen compounds discharged from four major permitted wastewater treatment plants (Saugus Water Reclamation Plant (WRP), Valencia WRP, Fillmore Publicly Owned Treatment Work (POTW), and Santa Paula POTW. These major point sources are assigned wasteload allocations for ammonia, nitrite, nitrate, and combined nitrite and nitrate. At the Regional Board's discretion, the Saugus and Valencia WRPs may be allowed higher interim loads for nitrate, nitrite, and combined nitrate and nitrite for a period as short as possible, but not to exceed eight years from the effective date of the TMDL. The Fillmore and Santa Paula POTWs may be allowed higher interim loads for combined ammonia, nitrate and nitrite for a period also not to exceed eight years after the effective date of the TMDL. Receiving water monitoring is required weekly of these major point sources.

Minor point sources (including stormwater sources) in Reaches 3 and 7 are also assigned concentration-based wasteload allocations for ammonia and combined nitrite and nitrate. Wasteload allocations for minor point sources will be implemented through effluent limits or Best Management Practices (BMPs) for stormwater. Load allocations for nonpoint sources for combined ammonia, nitrite, and nitrate are implemented through State Water Resources Control Board Management Practices.

The County Sanitation District of Los Angeles County (CSDLAC) must submit the results from a water effects ratio study for ammonia when the TMDL takes effect. Within one year after the effective date of the TMDL, the following workplans must be submitted to the Regional Board for approval:

(1) a workplan for estimating nitrogen loading from stormwater sources which includes triggers for conducting source identification and implementing BMPs must be submitted by affected MS4 (municipal separate storm sewer systems) permittees;

(2) a workplan for monitoring nitrogen-related effects and evaluate progress in meeting targets must be submitted by affected major National Pollutant Discharge Elimination System permittees; and

(3) a special studies workplan to evaluate site-specific objectives for nitrate must be submitted by CSDLAC. If monitoring and study results indicate it is appropriate, the Regional Board will consider adopting site-specific objectives for ammonia within one year after the effective date of the TMDL, and site-specific objectives for nitrate, and combined nitrite and nitrate within four years after the effective date of the TMDL. If site-specific objectives are adopted, the TMDL will be revised through a Basin Plan amendment. Five years after the effective date of the TMDL, the Regional Board will consider whether the numeric targets and wasteload allocations specified in the TMDL are sufficient to protect the Santa Clara River from nutrient effects of discharged nitrogen compounds or whether the TMDL must be revised through a Basin Plan amendment.

Cal. Code Regs. Tit. 23, § 3939.6

1. New section summarizing amendments to Basin Plan filed 2-27-2004; approved by OAL 2-27-2004 pursuant to Government Code section 11353 (Register 2004, No. 9).