Stanford University on May 1 released a long-awaited report on what it will do with its 123-year-old Searsville Dam, saying its preferred plan is to create an opening at the base of the dam to allow the passage of fish, including endangered steelhead trout, while preserving some of the flood control they say the dam now provides.
The 65-foot tall and 275-foot wide dam is located off Sand Hill Road west of Interstate 280, in the Jasper Ridge Biological Preserve on Stanford land, adjacent to Woodside. It holds back Corte Madera Creek to form the reservoir known as Searsville Lake.
The 41-page report says that if the first choice proves unworkable, second choice is to allow the lake to finish filling with sediment, a process already 90 percent complete. Stanford would then create a new stream channel through the stabilized sediment so fish could pass through, either using fish ladders or a rerouted stream channel.
In either case, Stanford would continue using water from the creek. The first alternative would allow eventual removal of the dam.
The report says the most critical aspect of the first alternative is whether or not the 2.7 million cubic yards of sediment now trapped upstream of the dam can either safely travel downstream through San Francisquito Creek to the Bay or be stabilized in place.
Stanford says the permitting process for either alternative will involve multiple agencies, could take years and that doing either project could cost up to $100 million.
Groups that have been urging Stanford to remove the dam said neither of the solutions is a good one. "Poking a hole in an unneeded dam or letting it fill in with sediment are not viable solutions," said Portola Valley's Matt Stoecker of Beyond Searsville Dam.
Mr. Stoecker said the university's proposed solutions "are unlikely to secure permits or attract funding support." He said that recent studies have shown that dam removal, combined with separate floodwater detention ponds, "can provide the greatest ecosystem benefit while also achieving elevated flood protection" that Stanford said it is striving for.
Los Trancos Woods resident and environmentalist Jerry Hearn, who served as co-chair of the Searsville Advisory Group, said the Stanford proposal is not perfect, but could work. "Ultimately, what I would have liked to have seen is the dam no longer being there and the streambed reshaping itself," he said. "I think this approach has the possiblity of getting there."
The issue is very complicated, he said, especially because the dam and reservoir are in the middle of the Jasper Ridge biological preserve and downstream from very highly urbanized area. San Francisquito Creek does not have "a lot of wiggle room for the water and the sediment," he said. "That has been what has been keeping many of us awake at night."
He speculated that it will take at least five years for Stanford to get permission to proceed with either alternative.
Environmental reviews and authorization will be required from many agencies, Stanford says, including: the U.S. Army Corps of Engineers, the National Marine Fisheries Service, the U.S. Fish and Wildlife Service, the California Department of Fish and Wildlife, the State Water Resources Board, the California Division of Safety of Dams, San Mateo County and the San Francisquito Creek Joint Powers Authority.
The recommendations are the result of four years of work by the Searsville Alternatives Study Steering Committee, made up of university administrators and faculty advised by a group of local officials, environmental advocates, neighborhood groups and stage agencies.
Steve Rothert, California director for American Rivers foundation, said his organization is "concerned that operating a dam with a hole in it will be more troublesome than they expect," he said, citing possible problems with fish passage and sediment accumulation. He said he believes Stanford will ultimately decide to remove the dam. "We expect they will reach that conclusion before too long as resource agencies weigh in," Mr. Rothert said.
Both Mr. Rothert and Mr. Stoecker are members of the Searsville advisory committee.
The report also recommends continued diversion of water from the creeks for Stanford's use.
The plan shifts water storage from Searsville to Felt Reservoir. The report says water now diverted at Searsville would most likely be moved to the existing San Francisquito Creek Pump Station, about 4.5 miles downstream from Searsville Dam.
"The recommendation regarding water diversion and storage is intended to preserve Stanford's rights to creek water diversion and storage considering the effects of climate change, population growth, and drought on the region's water sources," the report says.