Lagunitas Creek is a 20-mile long creek in Marin County that flows from the north-side of Mt. Tamalpais and enters the Pacific Ocean at Tomales Bay. Approximately half (48%) of the 110 square-mile watershed is in private ownership, and land uses include rural residential and agriculture. The remainder is under management by the National Park Service, open space districts, and municipal water agencies. Lagunitas Creek provides drinking water for much of Marin County, supported by two major reservoirs. Water supply reservoirs and their associated dams prevent fish migration to approximately half the watershed. The watershed has a long 30-year history of restoration activity completed by dedicated agencies, organizations and community volunteers. Instream fisheries enhancement and upslope sediment reduction have been the focus of community restoration efforts.
Lagunitas Creek is included on the federal Clean Water Act list of impaired water bodies due to pathogens, nutrients, and excessive sediment. Coho salmon in the Lagunitas watershed are state and federally listed as endangered; Chinook salmon and steelhead are federally listed as threatened. Preventing the extinction of coho salmon means restoring many key habitat attributes within the Lagunitas Creek watershed that are in poor condition.