America’s Most Endangered Rivers for 2014: San Francisquito Creek
Threat: Outdated dam
At risk: Threatened fish, wildlife habitat, and public safety
San Francisquito Creek is a natural refuge in an urban setting, providing recreation opportunities for nearby communities as well as a home to rare fish and wildlife. However, Stanford University’s 65-foot Searsville Dam blocks threatened steelhead from reaching 20 miles of habitat upstream, impairs water quality, and poses flooding risks for local communities. It is time for Stanford to remove this obsolete dam to restore the health of the creek and secure the safety of its communities.
Fueled by winter rains and year-round springs, the 45 square mile San Francisquito Creek watershed gathers dozens of small tributaries draining the Eastern Slope of the Santa Cruz Mountains through the towns of Portola Valley and Woodside. The San Francisquito mainstem, formed at the confluence of Bear Creek and Corte Madera Creek, flows for 12 miles east through Stanford University, and the cities of Menlo Park, Palo Alto, and East Palo Alto, before meeting the southern portion of San Francisco Bay, the largest estuary on the West Coast
This creek is unique because it remains one of the only San Francisco Bay streams that is not confined to a concrete channel. This fortunate circumstance exists because the creek serves as a boundary between San Mateo and Santa Clara counties, and the counties could never agree on a plan for its channelization. This political twist of fate protected the creek from the problems faced by most other urban streams. Additionally, much of the upper watershed has been protected as open space land to provide recreation activities for nearby communities. As a result, San Francisquito Creek largely retains its natural character despite its urban setting, and is home to many rare and threatened native species, including steelhead trout, red legged frog, western pond turtle, San Francisco garter snake, and tiger salamander. Significant stretches of the creek have been designated as critical habitat for these species and the Center for Ecosystem Management and Restoration named San Francisquito an anchor watershed for the recovery of wild steelhead trout in the bay.
Despite its relatively pristine condition, San Francisquito was not spared entirely. Below the confluence of several key tributaries stands Searsville Dam, owned by Stanford University. Built more than 120 years ago to provide drinking water, the 65 feet tall and 275 feet wide dam never served that purpose and is no longer needed for Stanford’s non-potable water supply, but it continues to cause significant harm to the creek and fish and wildlife that live in it. The dam and sediment it traps also pose safety risks to several nearby communities.
Searsville Dam is a complete barrier to steelhead trout, which depend on their ability to migrate out to the ocean and back into their natal streams to spawn. The dam blocks access to 20 miles of steelhead habitat upstream of the dam and reduces instream flows below the dam, often blocking all flows in summer. Additionally, the dam drowned the confluence of five creeks and extensive wetlands that provided important riparian habitat for many species of birds and other wildlife, replacing it with a slack water reservoir. The reservoir is bad for native species because it has lower water oxygen levels, higher water temperatures, supports invasive species and algae blooms, and encourages the loss of water through evaporation.
More than 90 percent of Searsville Reservoir is already filled in with sediment, eliminating its usefulness as a water storage facility. Unless Stanford takes action soon, the reservoir will fill in completely in coming years— sending rocks and debris over the top of the 65 foot dam, likely eroding the dam face as they fall. The U.S. Army Corps of Engineers, State of California, and San Mateo County characterize Searsville as a “high hazard dam,” meaning that a dam failure would cause significant economic losses, environmental damage, and human casualties.
What Must Be Done
Beyond Searsville Dam, a coalition of 34 conservation groups, including American Rivers, persuaded Stanford to study alternative futures for the dam, including dam removal. The Searsville Alternatives Study Steering Committee will present its recommendation to the University President and Provost at the end of 2014. Studies show that feasible alternatives exist to replace Searsville’s water storage and water diversion functions. Stanford must select an alternative that removes the dam to restore this unique creek while protecting local residents from flooding.
To find out more and to support our Beyond Searsville Dam coalition’s efforts to remove Searsville Dam, please visit BSD.org