Stanford engages consulting firms to help with Searsville study

Members of the media invited to an information session and Jasper Ridge Biological Preserve tour learn that the 120-year-old Searsville Dam is a "champion sediment producer" whose future requires careful study and consideration, given the complicated environmental issues involved.

Kate Chesley David Freyberg, professor of civil and environmental engineering, explains the construction and operations of the Searsville Dam to members of the media visiting Jasper Ridge this week.

David Freyberg, professor of civil and environmental engineering, explains the construction and operations of the Searsville Dam to members of the media visiting Jasper Ridge this week.

Stanford has engaged an engineering firm to conduct crucial engineering and biological studies at Searsville Dam and a company that specializes in public outreach to help engage external groups interested in the future of the dam and reservoir.

The two firms will help the Searsville Steering Committee continue its work in assessing what should be done with the 120-year-old dam, located in the university's Jasper Ridge Biological Preserve.

The engagement of the engineering firm URS and public outreach firm Kearns and West was among the news shared this week with members of the media invited to Jasper Ridge for a presentation and tour of Searsville Dam and Reservoir by the Searsville Steering Committee.

"This event was an opportunity for Stanford to better explain the complicated environmental issues surrounding the dam's future and to correct some misimpressions the public may have," said Jean McCown, director of community relations and co-chair of the steering committee.

The faculty and staff steering committee includes Stanford scholars who specialize in engineering, environmental science, history and law. They have been studying a range of alternatives for the future of Searsville Dam since 2011 and hope to complete an initial set of studies in early 2014.

Looking for the 'best solution'

The dam was built in 1892 by the for-profit Spring Valley Water Co. and acquired by the university in 1919. Today, sedimentation has reduced the reservoir to less than 10 percent of its original water capacity. The reservoir is one of several sources of non-potable water used at Stanford for landscape irrigation, agriculture and fire protection. The ecosystem created by the dam also is a key aspect of environmental research conducted at Jasper Ridge.

Kate Chesley Sedimentation has reduced the reservoir created by Searsville Dam to less than 10 percent of its original water capacity.

Sedimentation has reduced the reservoir created by Searsville Dam to less than 10 percent of its original water capacity.

Chris Field, professor of biology, co-chair of the steering committee and faculty director at Jasper Ridge, told reporters that the faculty members studying the dam's future are all accomplished scholars and "people who dedicate their lives to environmental problems."

Field assured reporters that the committee has been tasked only with finding the "best solution," factoring in the complex environmental issues and the concerns of the many constituencies affected by the dam and reservoir. He cautioned, however, "it's not obvious what the best solution is."

Although the lack of an expedient answer may frustrate some, he said he was "very confident about finding a solution that will work."

Champion sediment producer

But among the challenges the committee is wrestling with is the massive amount of sediment dumped into the reservoir from major winter rains in the Santa Cruz Mountains above the dam, according to steering committee member David Freyberg, associate professor of civil and environmental engineering.

Freyberg, whose research focuses on aging dams, said Searsville Dam was originally built to provide water to San Francisco. The dam and reservoir's purpose was to store water from the winter rainy season for use during the dry season of the year. Its flexible design, he said, is considered unique.

"Think of it like a large concrete Lego set of interlocking, poured-in-place concrete blocks," he said. The dam's mass, combined with gravity, is what keeps it in place. But from its first days, Freyberg said, the dam was what he called a "champion sediment producer because of the geography of the area."

Sedimentation has proven to be a challenge for Stanford's sustainable water management, according to Tom Zigterman, co-director of the staff Searsville Alternative Study Working Group and associate director of water services and civil infrastructure.

Kate ChesleyMedia representatives were given a tour of the Searsville Dam by members of the Searsville Steering Committee and the Searsville Alternative Study Working Group.

Media representatives were given a tour of the Searsville Dam by members of the Searsville Steering Committee and the Searsville Alternative Study Working Group.

Zigterman said Searsville Reservoir provides about 20 percent of the university's irrigation supply. Although the dam, which he called "structurally safe" as evidenced by annual inspections by the California Division of Safety of Dams, was never intended to operate as a flood-control facility, there is a perception by surrounding communities that it may play a role. He said the university is being "careful and aware" of potential flood impacts upstream and downstream of any proposed action.

Zigterman said there is no way to predict when sediment will completely fill the reservoir.

"Given that it has taken 120 years for it to fill in 90 percent, it's hard to say. It could be a decade. It could be several. But we don't want to wait for that," said Zigterman.

Possible options

The steering committee is considering many possible options for Searsville Dam, including:

• Continuing to allow the reservoir to fill with sediment and transition to a marsh and forested wetland

• Maintaining the dam and reservoir through sediment removal

• Modifying the dam and reservoir to enable flood mitigation and management, in addition to water supply and storage

• Removing the dam to allow Corte Madera Creek and other streams to flow downstream unimpeded

It is also considering other issues related to Searsville, including alternatives to the current water supply and storage facilities, provision of fish passage, the change in the amount of sediment going downstream and options for removing accumulated sediment from 12 decades of deposition.

In the meantime, McCown said the university's study of the dam and reservoir has attracted the attention of environmental organizations, some of which are focused on the welfare of the steelhead population that spawn in San Francisquito Creek.

McCown said Stanford is equally concerned about the steelhead population and has been working for more than a decade to improve the habitat for it and other protected species in the San Francisquito Creek watershed and on Stanford lands in general. She said she is confident that a National Marine Fisheries Service investigation of possible "take" of steelhead alleged to be caused by the dam would reflect the university's compliance with the Endangered Species Act. "Take" refers to the killing or harming of a threatened or endangered species.

Whatever solution the university proposes, consultation and permitting by at least six federal agencies and seven state agencies, in addition to local governments, will be necessary, she said.

The next step, McCown said, is completion of the engineering studies by URS and creation of an external advisory committee to help the university understand the community's perspective on the numerous options possible at Searsville Dam and Reservoir.

"For now, we are keeping an open mind and keeping everything on the table," she said.