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Issue date: May 31, 2000

Should Searsville Dam go?

When he was in high school, Matt Stoecker watched a steelhead struggling to climb Searsville Dam -- all 60 feet of it. The unsuccessful attempt by the 2-foot fish to reach its spawning grounds upstream in Portola Valley was a defining event for Mr. Stoecker. It helped crystallize his passion to get rid of the dam so that steeelhead, and possibly salmon, could once again swim upstream to the headwaters of Corte Madera Creek and its tributaries.

"Searsville Dam has outlived its function; it doesn't serve the purpose it was originally intended for," says the Portola Valley resident and stream ecologist. "I'd love to see steelhead be able to spawn at the base of Windy Hill."

No one disputes that the 1891 dam supports a vanishing lake. Searsville Lake, for more than 50 years one of the Peninsula's popular party spots, is today down to about 15 acres. It could be gone within decades, depending on the rate at which sediment washes down from the erodible hills bordering the San Andreas Fault in Portola Valley during winter rains.

"I'd give it about 15 years," says Philippe Cohen, director of Stanford's 1,200-acre Jasper Ridge Biological Preserve. He speculates that the dwindling lake will give way to wetlands and oak woodlands, threaded by Corte Madera Creek -- right up to the dam.

However, turning the clock back and removing a dam that has been in place for 108 years in a geologically -- and politically -- active watershed raises enormous concerns. Among them:

**What would be done with close to a million cubic yards of silt that has already replaced more than 90 percent of the lake's water?

**What would happen to the ecosystem that has been evolving over the last century?

**What effects would removal -- including possible flushing of sediment -- have on the recovering population of steelhead elsewhere in the watershed?

**Would removal of the dam alleviate upstream flooding problems suffered by residents of the Family Farm neighborhood in Woodside?

**How would removal of the dam affect flooding of San Francisquito Creek downstream?

**How would the removal of 60 feet of concrete blocks affect the biological preserve and surrounding communities?

**Who would pay the millions of dollars needed for studies and possible removal?

Dr. Cohen is reserving judgment until he knows more about how the proposed dam removal would affect habitats and the scientific experiments going on at Jasper Ridge. "In principle I'm not opposed," he says. "The issue is, what are the tradeoffs? And is it feasible? There are too many unknowns, but it's definitely worth exploring."

Mr. Stoecker, who has been promoting the removal idea in the press and with state and federal officials, agrees a major study is needed to answer these and other questions. He has talked with Sen. Byron Sher and taken an assistant of Interior Secretary Bruce Babbitt on a tour of the dam. Now he's approaching Stanford and the regional agencies concerned with San Francisquito Creek about launching a study. Such a study -- including geology, hydrology and biology -- might cost $2 million.

On Wednesday, June 14, at 2 p.m., Mr. Stoecker will make a presentation to the Joint Powers Agency (JPA) working on measures to improve San Francisquito Creek and address its flooding problems. The meeting will be in the Palo Alto City Council conference room at 250 Hamilton Ave.

Meanwhile, Stanford, which owns the dam, is willing to consider removal of the dam among other alternatives under study. These also include: leaving the dam in place, and lowering it 16 feet to improve drainage upstream.

"It's a long-term proposition," says Chris Christofferson, associate vice provost for facilities. "It's very complex; we are studying the options with an open mind."

Mr. Stoecker's proposal reflects serious interest nationwide in removing dams that no longer serve a purpose. To date, 455 dams, 47 of which are in California, have been removed to restore fisheries and improve habitat, Mr. Stoecker says. "If you really look over the long term, removal begins to make sense."

Disappearing lake

"This is a good piece of Arkansas," says Dr. Cohen, as he stands on Searsville Dam on a glorious Monday morning.

The artificial lake created by the dam represents a new environment, one that is alien to the natural creek that used to harbor runs of steelhead, now a threatened species in California. Warmed by the summer sun, the still water now supports a variety of non-native, and often destructive, creatures. Large-mouth bass, bullfrogs, sunfish, and exotic crayfish -- more suitable to Arkansas than the Peninsula -- live in the lake and sometimes spill over the dam to dine on native species downstream.

As puffy clouds spit rain, Dr. Cohen tours the dam with Mr. Stoecker and Jim Johnson, who serves as streamkeeper for CRMP (Coordinated Resources Management and Planning), a multijurisdictional organization working for restoration of San Francisquito Creek and its watershed.

On one side of the dam, sparkling droplets cascade down the concrete blocks to San Francisquito Creek 60 feet below. On the lake side, the bottom is now only 17 feet below the wavelets of what remains of Searsville Lake. Because of silting, the peaceful pond contains less than 10 percent of the water it held when the Spring Valley Water Company built Searsville Dam in 1891, Dr. Cohen estimates.

"It would be sad to remove all that bird habitat," comments Mr. Johnson, pondering what the area would be like without the lake or the dam.

Dr. Cohen wonders how the physical removal of the dam -- with jackhammers and bulldozers and the accompanying noise and dust -- would affect other habitat values, as well as the scientific experiments under way at Jasper Ridge. "We're doing long-term experiments in global climate change," he notes.

Sediment

The biggest problem associated with tearing down the dam is what to do with the sediment, Dr. Cohen reiterates. "It's pushing one million cubic yards of sediment. You could cover the whole town of Portola Valley in six inches of sediment."

That sediment sluices down from the erodible formations in the hills of southern Portola Valley during storms, and deposits in the lake, backing up water that periodically floods the homes of Family Farm.

The 1998 El Nino storms provide a dramatic example. "We lost almost 10 percent of the surface area of the lake during that one storm," Dr. Cohen says. "At the height of El Nino we were getting more than 20,000 tons a day of sediment."

Both major methods of sediment removal -- hauling it away or flushing it downstream -- pose huge problems that need extensive study. If the sediment is dug out of the lake, it has to be de-watered before it can be trucked away. "You need a place where it can dry out. That's 3 feet of sediment over 200 acres," says Dr. Cohen.

If the dam is lowered in stages and the sediment is allowed to flush downstream over a period of years, the issue becomes the effect of this process on the lower reaches of the stream and the current runs of steelhead.

"Siltation will increase downstream. Extra sediment could be deposited in the streambed, reducing the ability of the stream to hold water," Mr. Johnson warns. "We need a detailed feasibility study."

This summer, Stanford, in coordination with the JPA, will start a study to determine the impact of sediment on the creek downstream after the lake is full. "For 100 years, the dam has trapped sediment from upstream," Mr. Christofferson says. "At some time that sediment will go downstream, as is did before the dam was built."

The watershed

Issues surrounding Searsville Dam cannot be viewed in isolation because it controls somewhere between 20 and 35 percent of the San Francisquito Creek watershed. Rain that falls on the watershed's 44 square miles -- stretching from Page Mill Road to Kings Mountain on Skyline -- drains down gullies, creeks and streams through Woodside, Palo Alto and Portola Valley. They all join to flow down through Menlo Park and Palo Alto to San Francisco Bay in the ditch that is lower San Francisquito Creek.

In heavy storms, that ditch floods; in 1998 hundreds of homes in Menlo Park and Palo Alto were under inches to feet of water. Understandably, residents and the agencies that represent them are leery of upstream changes that might make flooding worse.

There are also the questions of how removing Searsville Dam would affect the existing steelhead run. Every year the anadromous fish swim from the ocean to spawn in the upper reaches of Bear Creek and its tributaries in Woodside, and Los Trancos Creek along the San Mateo-Santa Clara county line, where Stanford has installed a fish ladder.

Above Searsville Dam, there are no steelhead, only rainbow trout, which are steelhead that are landlocked. If the barrier posed by the dam were removed, these fish would swim to sea as steelhead, and return to spawn year after year.

Again, it will take a study to determine the effect of removing Searsville Dam on the present and potential steelhead runs in all three creek systems. Mr. Johnson notes, "For the same flows, Corte Madera Creek has 10 times the sediment of Los Trancos Creek."

Amazing fish

Growing up in Portola Valley, Matt Stoecker came to love Corte Madera Creek, fly fishing, steelhead and salmon.

Now that he's grown and trained as a stream ecologist, that love has transformed into his mission: to get rid of Searsville Dam and return Corte Madera Creek and its tributaries to the natural state of the last century.

"I've developed a passion for steelhead," he says enthusiastically. "Steelhead bring nutrients from the ocean and disperse them in the watershed. Steelhead are considered one of the best indicators of watershed health. I think the upper watershed is starving."

After attending schools in Portola Valley and Menlo-Atherton High School, Mr. Stoecker earned a degree in ecology at the University of California at Santa Barbara. His senior thesis is now a funded project to plan a steelhead recovery program for southern Santa Barbara County.

He also writes conservation articles for various publications, including the Almanac. His "Removing Searsville Dam: A Damn Good Idea" is featured in the spring issue of Headwaters, the magazine of Friends of the River.

Last fall, Mr. Stoecker returned from several months guiding of fly-fishing trips in Mongolia to take up the cause of Searsville. He is not discouraged by the obstacles to removing the dam, and points to the Matilija Dam in Santa Barbara County, which is now slated for removal. The dam and its watershed are similar to Searsville, only three times bigger, he says. Although total removal of the dam was thought at first to be a crazy idea, he says, it is "now widely agreed to be in everyone's best interest."

What next?

Mr. Stoecker has been working with Stanford and CRMP, as well as the state and federal governments, to generate interest and funding for a feasibility study of removing Searsville Dam.

One possibility is that Sen. Byron Sher might be able to include Searsville in his new bill, S.B. 1540, which calls for an inventory of dams in California that might be candidates for removal. If successful, this bill might also make some money available. "Searsville Dam may have outlived its usefulness," Sen. Sher says cautiously.

The U.S. Geological Survey may also be a player in the studies that need to be done. It has just launched a new cooperative program with CRMP to help with geologic evaluation of San Francisquito Creek and its watershed. "We want to engage citizens in a collaborative process," says Herman Karl of Menlo Park. "We'll assemble a team of experts that can bring information to bear on issues. We'll coordinate with other studies so we get the most out of each study."

Mr. Stoecker hopes that complete removal of the dam will be included in future studies, and that outside funding can be secured. He also has high hopes for his presentation to the JPA on June 14.

Dr. Cohen warns that there are too many projects that do more damage than the problems they were designed to correct. He says, "If we do it, let's do it right."

More information

Matt Stoecker will present his proposal to remove the dam to the Technical Committee of the San Francisquito Creek Joint Powers Authority on Wednesday, June 14, at 2 p.m. in the Palo Alto City Council conference room at 250 Hamilton Ave.

Mr. Stoecker, a stream ecologist with the Coast Range Ecosystem Alliance, can be reached at 796-9867, or by e-mail at matts@worldwaters.com.

The office for Jasper Ridge Biological Preserve can be reached at 723-1589.

"The History of Jasper Ridge: From Searsville Pioneers to Stanford Scientists" by Dorothy F. Regnery was published in 1991 by the Stanford Historical Society, P.O. Box 2328, Stanford, CA 94309.