Stanford plans to remove Lagunita Dam

Stanford University officials are looking at tearing down Lagunita Dam and restoring habitat for endangered steelhead in the San Francisquito Creek. The university is seeking approval from Santa Clara County officials for its architecture-and-site plan and grading.

The Lagunita Dam Diversion Project would remove the 119-year-old dam and restore 480 feet of the creek, improving fish passage with pools, shallows and native plants. The project would improve downstream water and sediment flow, according to the proposal before the Santa Clara County Zoning Administration, which was scheduled to be heard on March 1.

Because the dam spans Santa Clara and San Mateo counties, the university is seeking approvals for the 3.57-acre site from both jurisdictions simultaneously. Stanford spokeswoman Jean McCown said the university would seek permits from San Mateo County in April and is in the process of obtaining easements from some nearby residents. If approved, removal of the 8-foot-tall concrete structure could begin this summer with project completion in summer 2019, according to a county planning staff report.

In December 2017, the university received a $1.2 million ecosystem and watershed restoration grant from the California Department of Fish & Wildlife for the project. McCown did not specify the total cost for the project, but a grant application to Fish & Wildlife proposed the agency fund 30 percent and the university would pay for 70 percent of costs.

Lagunita Dam is located just north of the east end of Happy Hollow Lane near Alpine Road and near the Stanford Weekend Acres neighborhood in unincorporated Menlo Park. The creek is home to the Central California Coast Distinct Population Segment of steelhead. The structure dammed the creek water to create a flume that filled Lake Lagunita with drinking water. But the flume and dam have not been operational since the 1930s, McCown said.

Stanford added a fish ladder in 1954 to help the steelhead move over the dam, but the ladder was prone to debris jams that caused the steelhead difficulty navigating through the structure, according to a 2014 National Marine Fisheries Service biological opinion on the university’s Steelhead Habitat Enhancement Project.

The dam also creates about a 1,000-foot-long area of sediment upstream and a deep plunge pool downstream, which are not conducive for the steelhead to spawn, according to the university’s November 2017 funding application to the state Department of Fish & Wildlife. Two environmental organizations sued in 2014 claiming that Stanford had violated the Endangered Species and Clean Water acts by continuing to keep the dam in place.

The university and plaintiffs Our Children’s Earth and Ecological Rights Foundation reached a temporary settlement to stay the lawsuit and a separate legal action regarding Searsville Dam until Stanford could obtain regulatory approvals to mitigate two improvements: changing water flow at the Jasper Ridge Road Crossing and removing the Lagunita Dam. Stanford has completed the so-called low-flow crossing at Jasper Ridge Road by removing a concrete deck and adding a box culvert to move water under the roadway, McCown said.

Removing Lagunita Dam would increase the length and depth of water pools in the creek and improve gravel areas needed for spawning and fish passage, particularly in low-flow conditions. About 14.6 miles of high-quality habitat upstream of the dam would be created, according to the university’s Fish & Wildlife funding application.

In addition to removing the concrete structure, the project would remove sediment behind the dam and restore the stream with two pools and three “riffles” — rocky or gravel areas that produce shallows. The project will reconfigure 480 feet of stream channel by moving the creek banks further toward the university and away from Alpine Road and nearby residences. About 2,800 cubic yards of excavated material would be used in the restored channel and in a 5.50-acre terraced floodplain on the Alpine side, which would be revegetated with native plants and trees. Stream banks would also be stabilized with native plants, according to the application.

The project would remove and replace one to three oak trees and 33 non-oaks with 222 trees, based on a landscaping formula that replaces older trees with equivalents, according to the staff report.

Anadromous fish such as steelhead, which are species that are born in fresh water, spend most of their lives in the sea and return to fresh water to spawn, have benefited from dam removals, the university noted in its Fish & Wildlife grant proposal. Adult steelhead in upstream areas of the Carmel River appeared the first winter after the San Clemente Dam’s removal. Fall runs of Chinook salmon populations increased by a factor of four on Clear Creek in Shasta County after removal of the Saeltzer Dam.

Santa Clara County determined that the project is exempt from environmental review under the California Environmental Quality Act (CEQA) as a small habitat restoration project that is restoring fish passage. The state Department of Fish & Game also approved a notice of exemption from CEQA on March 20, 2017.

In a Feb. 27 email to county planners, Jerry Hearn, a former member of the San Francisquito Creek Watershed Council, said he supports the project.

“This particular structure has long been identified by the Council members and others as a very significant barrier to effective fish migration. The fish ladder affixed to it was an attempt to ameliorate this problem but was not very effective due to a number of issues. We all consider it best to remove the structure entirely as it no longer serves its water supply purposes. … The plans that have been produced to restore this reach after the dam removal are very apt to have a significant positive impact in improving the entire riparian corridor for the extent of the project, as well as having beneficial impacts to the reaches both upstream and downstream from it.”