The Guadalupe River has been substantially contaminated by mercury leachate from the New Almaden Mine, which operated from 1849 until the early 1900s. This contamination, now disbursed from the upper watershed to South San Francisco Bay, endangers beneficial uses of these waters, including reproduction of salmon and steelhead fisheries and other aquatic vertebrates. For that reason, the State Water Resources Control Board (SWRCB) has listed this creek as impaired under Clean Water Act section 303(d). Your grant allowed Natural Heritage Institute (NHI), as special counsel to the Guadalupe-Coyote Resource Conservation District (GCRCD), to undertake and complete technical research and settlement negotiations that will contribute to an effective removal or other remediation of the mercury contaminants in the channel substrate and waters of this creek.

First, mercury contamination in creek substrate or water should be remediated in the context of a comprehensive restoration program for the aquatic habitat. A coldwater fishery will not benefit from such remediation if the flow remains too warm for egg hatch, or if barriers prevent access by spawning adults to gravel, or if such gravel is absent due to gravel mining or other channel modification. Further, a public agency which may be liable under NRDA may also be liable under other laws for causing limiting factors other than toxic contamination, and its willingness or ability to pay for remedies should be allocated prudently to address all significant causes of degradation of the aquatic habitat.