Welcome to the State Water Resources Control Board - San Francisco Bay Welcome to the California Environmental Protection Agency
Governor's Website
My Water Quality
Performance Report

Walker Creek Mercury TMDL

On September 29, 2008, the U.S. Environmental Protection Agency approved the Basin Plan amendment incorporating a TMDL for mercury in the Walker Creek and Soulajule Reservoir watersheds. This amendment had been adopted by the Regional Water Board in January 2007 and became effective on September 11, 2008 when it was approved by California's Office of Administrative Law.

TMDL Implementation

STATUS UPDATE (09/13/13)
NEW - Opportunity for public comment on Renewal of Conditional Waiver of Waste Discharge Requirements in the Tomales Bay Watershed

STATUS UPDATE (05/31/2011)
This is a status report on the Tomales Bay Grazing Waiver Program. The report discusses the Grazing Waiver’s background and requirements, outreach efforts and funding, enrollee compliance, ongoing watershed efforts, and lessons learned.

Furthermore, the report describes the efforts of the Tomales Bay Watershed Grazing Land Partnership (Partnership) in assisting the agricultural community in complying with the requirements of the Grazing Wavier.

Staff believes that the success of the Grazing Waiver Program is rooted in the local relationships established with the Partnership, the substantial amount of technical assistance provided to ranchers by Water Board staff and the Partnership, and the success of partners in obtaining grant funding. The following two publications provide independent evaluations of the Tomales Bay Grazing Waiver Program:

For any questions regarding the Waiver or Waiver compliance, please contact Laurent Meillier at 510.622.3277 or e-mail laurent.meillier@waterboards.ca.gov.


Walker Creek, located in Western Marin County, California, is a 21-kilometer stream that flows through a former mercury mining district into Tomales Bay. The Walker Creek watershed supports steelhead and coho salmon, a diverse array of wildlife, and recreational fishing in Soulejule Reservoir. Mercury-laden sediment originating from inactive mercury mine sites threatens wildlife such as fish-eating birds, and also humans who consume fish from the reservoir.

The TMDL for mercury in the watershed includes a broad-based implementation strategy for reducing both mercury discharges and methylmercury production. In recent years, the Water Board and U.S. EPA collaborated in highly successful cleanup efforts at the Gambonini Mine site (the greatest source of mercury in the watershed). Reductions already achieved in the amount of mercury coming off the mine site indicate that when parties in the watershed work together, water quality in Walker Creek will once again support a healthy fishery and the wildlife that depend upon it.

downstream depositional area in Walker Creek

For more information, contact:
Carrie Austin
Environmental Engineer
San Francisco Bay Regional Water Quality Control Board
1515 Clay St., Suite 1400
Phone: (510) 622-1015
Fax: (510) 622-2460
E-mail: CAustin@waterboards.ca.gov