Guide to San Francisco Bay Area Creeks
Coyote Creek Watershed
The Coyote Creek watershed is the largest in the Santa Clara basin, comprising 350 square miles of land that drains into Coyote Creek and its tributaries.
The adjacent map highlights the Coyote Creek watershed that drains to the baylands and marshes of San Francisco Bay, directly below the confluence of Lower Penitencia Creek and Coyote Creek. North and west of this point, Coyote Creek is a tidal slough that extends to its confluence with Mud Slough. The upland area that drains to the confluence of Coyote Creek and Mud Slough also includes the map area outlined in white. This additional area includes land drained by Laguna Creek, Mission Creek, Scott Creek, and other smaller creeks and engineered ditches.
Today, the altered watershed functions differently. Coyote and Anderson dams, built to impound water for irrigation, groundwater recharge, and municipal water supply, also trap sediment from the upper watershed and regulate flow of Coyote Creek, preventing much of the natural alluvial-fan and floodplain deposition. Construction of levees and engineered channels, which protect neighborhoods from damaging floods, also restricts the natural migration of stream channels across alluvial fans and floodplains. Over-pumping of groundwater - first for irrigation, later for drinking water and industry - necessitated the importation of water from outside the Santa Clara basin and construction of percolation facilities to maintain groundwater levels and prevent subsidence of the valley floor. Storm water that formerly infiltrated the porous alluvial soil to replenish groundwater reservoir now mostly runs off impermeable rooftops and streets into underground culverts or engineered, concrete-lined channels leading directly to Coyote Creek. Natural willow groves, marshes, and riparian corridors are largely gone - drained, or altered to accommodate expansion of the population.
Stream Restoration, Rehabilitation, and Improvement
A Healthy and Safe Environment for All
Larger-scale examples include the 1996 Santa Clara Basin Watershed Management Initiative (WMI), and the 2002 Santa Clara County Water Resources Protection Collaborative. In 2000, the enabling legislation of the Santa Clara Valley Water District was amended to recognize stewardship as a purpose of the agency, and over two-thirds of Santa Clara County voters approved a special tax measure sponsored by the District to fund “Clean, Safe Creeks and Natural Flood Protection” for fifteen years. The District, with advice from WMI stakeholders, produced a stream stewardship plan for the Coyote Creek watershed in 2002. The plan includes over sixty projects to benefit flood protection, habitat enhancement, parks, and trails. Similar stream stewardship plans were produced in 2005 for the District’s Guadalupe, West Valley, and Lower Peninsula watershed management areas.
All of these processes require a significant commitment of time and money, and active participation from local agencies and community volunteers, but they can result in substantial improvement in planning for stewardship of local resources. This map highlights examples of current projects with multiple benefits in the Coyote Creek watershed.
-- Stephen C. Thompson & Janet M. Sowers
See accompanying page on Santa Clara Valley Land Subsidence.