Activist group targets Searsville Dam

Saying the time is now to get Stanford University to commit to removing Searsville Dam, a group of local activists galvanized more than 200 people at a kickoff event Tuesday evening.

Beyond Searsville Dam Coalition, spearheaded by Portola Valley native Matt Stoecker, gave a slideshow presentation and talked to a crowd that packed the outdoor-gear store Patagonia on Alma Street in Palo Alto, which hosted the event.

Steelhead trout have historically inhabited the creek and many tributaries flowing into San Francisco Bay, according to a 2004 report prepared for the San Francisquito Creek Joint Powers Authority (JPA).

The dam, which was built by the Crystal Springs Water Company and completed in 1892, is the biggest limiting factor to steelhead spawning in San Francisquito Creek and its tributaries. It blocks 10 miles of habitat, he said.

Stoecker said there’s more to his mission than just recreating a gateway for the fish. And he doesn’t want to restore the creek to go fishing.

“People accuse me of being a crazy fish head and it’s true,” Stoecker said. But “it’s not just an issue for our watershed.”

The steelhead is an “umbrella species” that supports many other animals. The fish can swim across the entire northern Pacific Ocean to Japan where it provides food for whales and ocean birds, Stoecker said.

He flashed images on the screen of birds, frogs and snakes all affected by the trout locally. A kingfisher plunged into the creek waters to snag a steelhead; an osprey snatches a fish out of the water and takes wing over the foothills.

Stoecker has been waging a lonely campaign for 10 years, ever since he saw a steelhead vainly try to breach the 60-plus-foot-high dam.

Stanford is currently seeking approval for a 50-year Habitat Conservation Plan from federal and state officials that would be the guiding principle of conservation, restoration and areas of potential development.

Stoecker and supporters want Stanford to put dismantling the dam into the Habitat Conservation Plan, he said.

Stanford favors dredging the sediment and keeping the dam, a position favored by scientists at Jasper Ridge Biological Preserve, where Searsville Dam is located.

Searsville Dam has been silting up for 119 years. Nearly 90 percent of its water-holding capacity is blocked with sediment. The dam is expected to top off with sediment in 15 to 40 years, depending on environmental factors such as storm events, erosion and earthquakes, according to scientific reports.

Jean McCown, a Stanford spokeswoman, said the Habitat Conservation Plan proposes to keep the Searsville Dam as it is. If the university were to propose at a future date to make changes in the dam it would commission a study to evaluate fish passage.

If no change is made, the Habitat Conservation Plan commits Stanford to a study in 10 years, she said.

The university has been considering what to do with the dam since at least the late 1990s.

Possibilities include dredging the sediment, removing the dam or allowing the dam to fill with silt.

McCown said the university’s perspective is summed up in a position paper by the Jasper Ridge Advisory Committee.

Jasper Ridge officials’ views are “first among equals,” she said.

The document supports dredging as the best alternative and outlines assessments for each option, including dam removal.

A restored stream provides the best opportunity for steelhead habitat, but successful restoration is not certain, committee members said.

“Managing a century’s worth of sediment accumulation so the impacts are benign presents enormous challenges.

“Removing Searsville Dam would be a highly experimental project. The large size of Searsville Dam, the alluvial fan character of the creek and the urbanized floodplain combine to make removal complex and challenging,” the committee wrote.

Removing the dam would be a huge undertaking and its removal is not as straightforward, or necessarily beneficial, as proponents would have people believe, according to Philippe Cohen, administrative director of Jasper Ridge Biological Preserve.

“Conditions have changed a lot. … (Stoecker) often cites other places where dams have been removed. In most cases, they were structurally unsound, so it was a non-issue. Very few of the others are located where the lower flood plain is fully developed,” he said.

When Searsville Dam was built, the residential areas downstream were sparse, Cohen said. The main problem with removing the dam today is that sediment currently being held back behind the dam would flow further downstream, through creeks in Woodside, Portola Valley and Palo Alto, then further through the San Francisquito Creek to East Palo Alto and the San Francisco Bay. No one knows exactly what that would mean for residents, he said.

“With the change in the amount of sediment, how it’s going to change flooding is a really tricky question,” he said.

Searsville Lake, created by the dam, has also changed the freshwater ecosystem, providing habitat, feeding and breeding and wetlands for countless species of birds, bats and other creatures, he said. Removal of the dam could change that the ecosystem, he said.

Steve Rothert, California regional director of American Rivers, which has helped get numerous dams removed, said Tuesday night there are ways to prevent downstream problems after the dam is removed.

Most dam-removal projects receive funding to prevent downstream flooding while the structures are being removed.

Computer modeling for other projects proved to be accurate in figuring out where problems could occur, he said. The creeks were reconfigured in places to take into account sediment erosion and deposit further downstream, and levees were raised in some areas.

Concerns about losing open-water habitat, which Searsville Lake now provides to waterfowl, can be lessened by creating other ponds and lake areas that would handle some of the runoff after the dam is removed, he said.

Taking steps to ease sediment and flooding problems for the similarly sized San Clemente Dam in the Carmel area costs an estimated $70 to $80 million. Much of the costs are paid for by funding from federal, state and private sources, he said.

McCown said Stanford has not singled out dam removal but hasn’t done a study.

Stanford is studying the problem, Cohen said.

Its Department of Civil and Environmental Engineering has been working on studies in the last four years related to the accumulation and management of sediments and how water flows through the system.

David L. Freyberg, a professor of civil and environmental engineering, is also studying how removal or alteration of the dam would impact the movement of sediment.

This summer, the department will research the sediment-reservoir-wetland interactions between the inflowing streams and the large sediment deposit trapped in the reservoir. Researchers hope their work will help make management decisions about the dam.

“The more difficult question is whether it would be cost-effective to remove the dam — whether the benefits would justify the costs,” Freyberg said.

He said the costs would be challenging to estimate but that they would likely be “very substantial.”

Among the concurrent goals would be:

– not damaging or destroying the mission of and ongoing research at Jasper Ridge Biological Preserve

– managing the sediment currently retained in the reservoir

– managing the increased downstream transport of sediment after removal

— compensating for the loss of upstream wetlands and wildlife.

These would have to be evaluated relative to the benefits to the steelhead, he said.

Stoecker and Rothert said their groups will try to pressure Stanford, holding informational meetings, engaging residents in letter-writing campaigns, adding a legal and outreach component and forming student-based groups.

Any project wouldn’t happen overnight. They estimate some current dam-removal projects will take 10 years or more to complete.

San Francisquito Creek watershed is the last in the Bay Area to remain in a natural state, meandering 44 square miles and emptying into the bay, Stoecker said. Most others have been straightened or confined to cement channels.

“We have an amazing opportunity to improve the watershed health,” he said.

Other longtime watershed supporters are not yet committing to a position on the dam. The Committee for Green Foothills was considering a position a few months ago but decided not to make a commitment until the factors related to downstream flooding are known, said Lennie Roberts, San Mateo County advocate for the committee.

There needs to be much more study of the potential impacts, she added.

“There are a lot of countervailing concerns,” she said.