NOTICE: Public Workshop and CEQA Scoping Meeting – Delta Mercury Control Program and TMDL Review

From the Central Valley Regional Water Quality Control Board:

Staff from the Central Valley Regional Water Quality Control Board (Central Valley Water Board) will hold an online public workshop and California Environmental Quality Act (CEQA) scoping meeting pursuant to California Code of Regulations, title 23, section 3775.5 to discuss and solicit comments and suggestions from the public regarding a proposal to:

  • Amend the Water Quality Control Plan for the Sacramento and San Joaquin River Basins (Basin Plan) as appropriate to include Phase 2 requirements within the Delta Mercury Control Program and associated Total Maximum Daily Load (TMDL), collectively referred to as the DMCP;
  • Consider adoption of a mercury offsets program; and
  • Consider whether or how to maintain the Mercury Exposure Reduction Program (mercury education and outreach to community groups).

On 22 April 2010, the Central Valley Water Board amended the Basin Plan to include the DMCP. The United States Environmental Protection Agency approved the TMDL with an effective date of 20 October 2011. The TMDL is being implemented through a phased approach; Phase 1 began 20 October 2011. At the end of Phase 1, the Basin Plan requires the Central Valley Water Board to conduct review of the Phase 1 requirements and to consider revising the DMCP and future requirements before starting Phase 2.

A phased TMDL approach was selected because additional information about methylmercury source control methods was needed to determine how and if dischargers can attain the current interim load and waste load allocations listed in the TMDL. Information was also needed about the methylmercury control methods’ potential benefits and adverse impacts to humans, wildlife, and the environment. Therefore, Phase 1 emphasized studies and pilot projects to develop and evaluate management practices to control methylmercury.

Phase 1 studies are now complete. If the Central Valley Water Board does not review and/or revise the DMCP by October 2022, the current load and waste load allocations would become immediately effective with a compliance date of 2030. As currently written, during Phase 2, dischargers would implement methylmercury control programs to meet allocations, continue inorganic mercury reduction programs, conduct compliance monitoring, and implement upstream control programs.

Board staff will review and, if necessary, consider proposing modification of the following: aqueous methylmercury and inorganic mercury goals; site-specific water quality objectives, currently established to protect Commercial and Sport Fishing (COMM) and Wildlife Habitat (WILD) beneficial uses; linkage analysis; allocations; the final compliance date; and requirements and schedules for implementation of methylmercury management practices. Board staff will also evaluate other potential public and environmental benefits and negative impacts (e.g., habitat restoration, flood protection, water supply, fish consumption) of implementing methylmercury management practices. Modifications to the DMCP will be based on the findings of the Phase 1 control studies and other recent information.

Additional information regarding this study and proposed amendment is available at the Central Valley Water Board’s Sacramento-San Joaquin Delta Methylmercury TMDL website.

Delta Mercury Control Program and Total Maximum Daily Load Review
Online Public Workshop and CEQA Scoping Meeting 24 February 2021
24 February 2021
9:00 AM – 12:00 PM

View/download the full notice below:

Delta TMDL and DMCP Review Meeting Notice


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