On October 8, 2008, the San Francisco Bay Regional Water Quality Control Board adopted Resolution No. R2-2008-0089 amending the Water Quality Control Plan for the San Francisco Bay Region because waters in the Guadalupe River watershed are impaired by mercury. This amendment establishes for the Guadalupe River watershed two new fish tissue-based water quality objectives for mercury; mercury total maximum daily loads (TMDLs) for seven waters (Alamitos Creek, Guadalupe Creek, Guadalupe River, Guadalupe Reservoir, Almaden Reservoir, Calero Reservoir, and Lake Almaden); an implementation plan to reduce mercury to meet the new TMDLs and implement the new water quality objectives; and a mercury monitoring program. It also vacates an outdated water-column water quality objective (four-day average of 25 ng/l) in the above-mentioned waters.
The implementation plan requires cleanup and abatement of mercury mining waste at mine sites by December 31, 2018. Through existing regulatory controls such as waste discharge requirements and Clean Water Act section 401 certifications, the implementation plan also requires projects proposed within depositional areas downstream of mine sites to minimize erosion. Further, the implementation plan requires the Santa Clara Valley Water District to undertake methylmercury production and control studies and to continue the operation, maintenance and improvement of methylmercury controls in its lakes and reservoirs. Finally, the implementation plan requires urban stormwater runoff agencies to determine whether urban runoff contributes to methylmercury production and bioaccumlation.
Cal. Code Regs. Tit. 23, § 3919.7