Stanford removes dam, giving endangered fish room to roam

Water is now flowing freely along a 480-foot stretch of San Francisquito Creek after Stanford University removed the aged Lagunita Diversion Dam.

The 120-year-old dam was located north of the east end of Happy Hollow Lane near Alpine Road and near the Stanford Weekend Acres neighborhood. The latter is in unincorporated Menlo Park. Removing the 8-foot-high structure now allows water to flow freely downstream to support endangered-fish-species habitat in the creek. San Francisquito is home to a population of the Central California Coast Distinct Population Segment of steelhead.

Removal of the concrete structure began in June 2018 and took five months to complete, according to the university. This section of the creek has been restored to include large rock boulders, logs and crib walls to create pools and riffles (rocky shallows) similar to other parts of the creek favored by the steelhead.

The dam was part of a decades-old controversy regarding Searsville and Lagunita dams. Two environmental groups, Our Children’s Earth Foundation and Ecological Rights Foundation, sued Stanford in 2014 claiming that the university had violated the Endangered Species and Clean Water acts by continuing to keep the Lagunita Dam in place.

The dam created a flume that filled Lake Lagunita with drinking water, but the flume and dam have not been operational since the 1930s, according to the university. Stanford added a fish ladder in 1954 to help the steelhead move over the structure, 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 created about a 1,000-foot-long area of sediment upstream and a deep plunge pool downstream, which impeded the steelhead from spawning, according to the university’s November 2017 funding application to the state Department of Fish & Wildlife.

The university and plaintiffs reached a temporary settlement to halt the lawsuit and a separate legal action regarding Searsville Dam until Stanford could obtain regulatory approvals to change water flow at the Jasper Ridge Road Crossing and remove Lagunita Dam. Stanford has completed the so-called low-flow crossing at Jasper Ridge Road.

Removing the structure and adding the improvements created about 14.6 miles of high-quality habitat upstream of the dam.

“Looking ahead, we have a 10-year monitoring plan to keep an eye on the improvements that were constructed at the site and make sure the structural components and vegetation remain in place,” Tom Zigterman, director of water resources and civil infrastructure for Stanford, said in a statement to Stanford News Service.