Stanford’s plans for removal of the 119-year-old Lagunita Diversion Dam, located in the San Francisquito Creek near Alpine Road, were approved by Santa Clara County on March 1. Plans for removal have been underway since a district judge ordered Stanford to remove the dam on Jan. 16, 2015, following concerns regarding fish passage and sediment flow.
Meanwhile, the much larger 125 year-old Searsville Diversion Dam still stands 65 feet tall at the base of the very same creek. Originally acquired from Spring Valley Water Company in 1919 to contribute to Stanford’s water supply, the dam now gives rise to many of the same environmental issues as the Lagunita Dam and provides little water. Since 2011, the dam’s environmental impact has undergone numerous assessments, while University faculty, researchers and environmental stakeholders have deliberated how and whether to remove or modify it.
Since the release of a list of formal alternatives in 2015, the University has been conducting various studies to determine the potential consequences of these options. The Daily took a closer look at the history of Searsville Dam and the issues being taken into consideration as this process moves forward.
The issues surrounding the Searsville Dam are primarily concerned with fish blockage and sediment passage. In particular, steelhead trout, an endangered species that inhabits the San Francisquito Creek, face a greater risk of extinction since the dam completely blocks them from swimming upstream, and their access to their habitat is more limited.
In Jan. 2013, two environmentalist groups, Our Children’s Earth Foundation and the Ecological Rights Foundation, filed a federal lawsuit against Stanford for harming the steelhead population and violating the Endangered Species Act, a 1973 piece of legislation signed into law by President Nixon that aims to protect endangered species from extinction and temper the “consequence of economic growth and development untempered by adequate concern and conservation.”
At the time, University spokesperson Lisa Lapin claimed Stanford was not harming the trout, referring to the creek as a “thriving steelhead habitat.”
Other issues include sediment accumulation, since the Searsville Lake traps all sediment that is delivered from upstream areas.
The accumulation of sediment results in another issue: flood risk. Given the 4.5 million cubic yards of sediment behind the dam, the reservoir is only at 5 percent of its original capacity, causing it to fill up at a dangerous rate.
“The way our watersheds work around here is that the [San Francisquito Creek] length is quite short, so if it rains up [at Jasper Ridge] at noon, at three in the afternoon there’s going to be a flood in Palo Alto potentially,” said Jasper Ridge director Chis Field Ph.D. ’81. Field is co-chair of the Searsville Dam and Reservoir Steering Committee, a group that examines potential alternative strategies for modifying or removing the dam and put together the 2015 Recommendations.
In addition to increasing flood risk, the dam’s low capacity means it no can no longer significantly contribute to campus irrigation.
A number of environmental groups, such as Beyond Searsville Dam, advocate for the removal of the dam entirely. The University has resisted large-scale structural changes for a number of reasons, a major one being cost.
“The challenge of next steps with improving the watershed at the Searsville area are going to cost the same as a major academic building or 25 professorships or tuition for thousands of students,” Field said.
Other concerns revolve around the logistics of removing the 4.5 million cubic yards of sediment that have accumulated behind the dam in the Searsville Lake. To remove it entirely would require hundreds of truckloads, which is would be costly as well as cause pollution and traffic increases in the surrounding area.
One environmental activist, however, thinks that there is a way to remove the dam without completely removing the sediment. Matt Stoecker is the founder of Beyond Searsville Dam, a coalition dedicated to advocating for removal of the dam. He described a procedure which would allow sediment from the dam removal project to empty into the San Francisco Bay—a more cost-effective and environmentally-safe method.
The Steering Committee has taken this option into consideration in its 2015 alternatives, and has begun research to predict its feasibility.
“All of the analysis that we’ve done so far suggests that the fine sediment would flow to the bay without any meaningful increase in flood risk,” Field said.
However, because the flood risk still remains, sediment release procedures are still under review. Currently, Stanford is developing a set of computer models in coordination with experts from the Bureau of Reclamation, the Santa Clara Valley Water District (SCVWD) and the National Marine Fisheries Service to analyze potential risks, including above-average creek flow which may result from major storms. The University is also in consultation with the San Francisquito Creek Joint Powers Authority (JPA) and the SCVWD to determine the nature of the creek’s current and how modifications to the dam will impact sediment flow.
A history of deliberation
In 2010, Stanford’s plans for Searsville in the University’s 2010 Habitat Conservation Plan (HCP) stirred controversy due to its lack of a commitment to long-term structural changes to the dam. The plan, which aimed to address issues surrounding endangered species such as steelhead trout, discussed dredging and potential research into fish bypass measures in the Searsville Dam, but did not detail any plans for dam removal.
In a statement released by Beyond Searsville Dam following the release of the HCP, National Marine Fisheries Services Supervisor Gary Stern referred to the HCP as “biologically inadequate” for achieving its goal of protecting endangered species as a result of a “significant lack of quantifiable data, inadequate analysis, significant errors and critical omission of key factors.”
The Center for Ecosystem Management and Restoration, another environmentalist group, demanded that the draft of the HCP be retracted entirely and rewritten to “provide adequate environmental review,” or a more thorough analysis of the impact of the dam on the steelhead population.
Similar opinions from the public comment period following the HCP as well as push from environmental and governmental agencies such as the San Francisquito Creek JPA prompted the University to form the Steering Committee in 2011, as well as an Advisory Group of representatives from the groups that criticized the HCP. In April 2015, the Steering Committee released their 41-page file documenting their analyses and recommendations as well as recommendations and comments from the Advisory Committee.
The primary recommendation, listed as Alternative 1-A in the document, is to cut a 50-foot hole in the bottom of the dam’s base to release sediment and allow fish passage.
Stoecker, however, sees a number of problems with this alternative.
“It’s a little bit naïve to think that [cutting a hole is] a viable solution,” he said. “The impact would be a whole bunch of new construction in the channel, and it’s unclear whether or not fish passage would even be achieved with it.”
Though the Steering Committee’s recommendation claims that the orifice would permit fish passage, Stoecker and members of Beyond Searsville Dam point to the anticipated accumulation of debris in the hole, the potential for steelhead to get trapped inside, and the disturbance to the steelhead population during its construction as issues with Alternative 1-A.
Stoecker also cited the dam’s age and pre-existing cracks in its structure as obstacles to cutting a hole in it.
“It’s a serious modification to the structure, and it obviously weakens the structure, so there would have to be a massive retrofitting of the structure to meet modern seismic and structural safety criteria,” he said. “I think that in a lot of ways it’s just cost-prohibitive.”
In its analysis, the Steering Committee did not provide cost estimates for the presented alternatives.
However, members of the Steering Committee said they believe Alternative 1-A will allow for a reduction in flood risk.
“Under normal conditions, the creek just flows through this hole, and under conditions of incredibly heavy rainfall, the hole would be too small for the whole creek to flow through,” Field said. “The basic idea of this is that our creek is a little trickle 99 percent of the time, but that one percent of the time when it’s a big torrent, there [won’t be] a big risk of flooding…if there’s a hole.”
According to the 2015 document, the plan is contingent on whether Stanford determines that sluicing of sediment downstream — rather than removing it completely with trucks — is feasible. The plan would also require coordination with external organizations and the JPA to maintain the downstream channel’s sediment accumulation and avoid flood risks.
The effects of this maintenance are of concern to Beyond Searsville Dam as well.
“This is right in the middle of Jasper Ridge Biological Preserve, so if … every few years or decades, the reservoir fills in with water and silt, you’re basically destroying the habitat periodically, having huge chronic impact on habitats and species that move back into that habitat and then get flooded out,” Stoecker said.
Considering the uncertainty of some of these issues, Alternative 1-A does not preclude dam removal, according to the document.
“[If] it is determined that complete removal of the Dam will not cause unacceptably high negative biological impacts in the watershed, then full removal of the Dam might be warranted,” the document said.
As its secondary recommendation, referred to as Alternative 1-B, the Steering Committee suggested the construction of a fish ladder or rerouted creek to allow for fish passage. Alternative 1-B is based on the assumption that releasing sediment downstream is infeasible.
Instead, this recommendation requires sediment to be stabilized behind the dam, or lifted up to create upland terraces and be used as topsoil. Alternative 1-B also requires coordination with the JPA and outside organizations to maintain the downstream creek channel and prevent flooding.
Members of Beyond Searsville Dam said they take issue with this alternative due to the required maintenance and debris removal. They added that a fish ladder may make it more difficult for steelhead to travel through the dam by tiring them out before they face predators in the reservoir, putting them at a greater risk for extinction.
Both recommendations pose risks to the Jasper Ridge Biological Preserve, which will likely be disrupted by the inevitable construction necessary to make the changes.
“The dam, of course, produced Searsville Reservoir, providing lake habitat and surrounding wetlands, which ultimately enhanced the biodiversity of the region,” Jasper Ridge director Anthony Barnosky wrote in an email to The Daily. “Whatever the ultimate fate of Searsville Dam, the reservoir will eventually disappear, which will cause a transition in the area. One of our goals … is to minimize these disruptions as well as any unanticipated long-term impacts of the construction activities.”
Since the the recommendations were released in 2015, Stanford has met with various outside organizations and is conducting studies on the published alternatives to determine the best possible solution based on anticipated environmental impacts.
“Stanford has been actively working to conduct the various engineering analyses and design efforts necessary to prepare and file applications for regulatory authorizations to implement the recommendations that resulted from Stanford’s Searsville Alternatives Study,” Jean McCown, co-chair of the Steering Committee and assistant vice president and director of community relations, wrote in an email to The Daily.
Daniel Freyberg, a civil and environmental engineering professor and member of the Steering Committee, predicts the release of another recommendation on the best possible course of action within the 2018 calendar year.
“We’re gradually learning more about the cost and benefits of different alternatives, and at some point in the not-too-distant future, I think the University will be ready to say, ‘This is our preferred alternative,’” he said.
The final decision ultimately lies in the hands of Stanford’s Board of Trustees. Following its decision, however, further action will be delayed until the University obtains the necessary permits and approvals needed to move forward with construction.
“It’ll be a long time after that before things change,” Freyberg said.
Regardless, movement towards change, both with Lagunita and Searsville, is a positive indicator for environmental groups.
“I hope that this experience with Lake Lagunita is kind of a small-scale version of what will happen with [the] Searsville Dam,” Stoecker said. “I hope that myself and … others at Stanford will … really take more pride in the creek that flows through the campus and earn the environmental stewardship that they claim to be practicing.”
Contact Julia Ingram at jmingram ‘at’ stanford.edu.