Fremont Weir Groundbreaking Marks Milestone for Yolo Bypass Fish Passage


Fremont Weir on Sacramento River's right bank.

Fremont Weir on Sacramento River's right bank in September 2016. DWR/2016

Today, the California Department of Water Resources (DWR), U.S. Bureau of Reclamation, and California Natural Resources Agency celebrated the groundbreaking of a critical habitat improvement project in the Yolo Bypass. The Fremont Weir Adult Fish Passage Modification Project restores an important migration corridor for native fish species and fulfills requirements set forth in the 2009 National Marine Fisheries Service’s Biological Opinion.

“This project highlights the complexity and competing needs of our system. But moreover, it showcases a solution,” said DWR Director Karla Nemeth. “Our work as water managers in the 21st century is to steward California’s diversity and beauty, while also ensuring public safety and water supply reliability. We can no longer choose one over the other. It’s not a trade-off analysis. We can and must ensure that all of our complex projects achieve multiple benefits, guided by a vision of long-term sustainability and public safety amid a changing climate.”

The Yolo Bypass is a critical part of the state’s flood control system, receiving flood waters from major rivers including the American, Sacramento, and Feather. When flooded, the bypass becomes one of the largest seasonal floodplains in the Delta, and a migration corridor for dozens of native fish species including Chinook salmon, steelhead, and green sturgeon.

The Fremont Weir, constructed almost 100 years ago to protect the region from flood waters, poses an obstacle for anadromous fish returning to their spawning grounds. The fish ladder currently in place provides inadequate fish passage, causing migratory delay and loss of life. The Fremont Weir modification project modernizes the structure and widens the channel through which the fish swim to ease their passage to upstream habitat.

This project complies with the 2009 National Marine Fisheries Service’s (NMFS) Biological Opinion on the Long-Term Operations of the Central Valley Project and State Water Project. The 2009 NMFS Biological Opinion recognized the importance of floodplain rearing habitat in, and fish passage throughout, the Yolo Bypass and requires DWR and Reclamation to complete several projects that accomplish these goals.

“We are pleased to provide the funding for the Fremont Weir construction effort as part of our work under the 2009 NMFS Biological Opinion,” said Reclamation Mid-Pacific Regional Director David Murillo. “The Fremont Weir is a prime example of what we can do when state and federal partners work together for water supply reliability in California. The State Water Project and the Central Valley Project are inextricably linked, and we have to work together, as we have done with this project, if we are to meet the needs of Californians.”

This project is part of a larger vision to restore Delta habitat for native fish and wildlife. Launched three years ago by Governor Edmund G. Brown, the California EcoRestore Initiative is a multi-agency effort to accelerate the restoration of at least 30,000 acres of critical Delta habitat. Six EcoRestore projects are breaking ground this year. Three of the six projects are required mitigation for the State Water Project and Central Valley Project, and the other three support landscape-level tidal and floodplain restoration in the Delta.

“Today we celebrate both the indomitable spirit of California’s native fish, and the indomitable spirit of those working to protect them,” said California Natural Resources Secretary John Laird. “Through large-scale conservation actions, we can begin reversing trends of species declines, and create the healthy environments we all want future generations to experience. This project turns what is primarily a flood control facility into one that serves multiple benefits. May today be but the first celebration in a year full of reasons to celebrate.”


The EcoRestore Initiative represents a deep commitment from a broad range of stakeholders to restore the Sacramento and San Joaquin watersheds in an effort to protect water supplies, ensure public safety, steward our natural resources, and improve salmon runs.

“These types of multiple benefit projects are the future of California water management and demonstrate that collaboration among diverse stakeholders can resolve even the thorniest water challenges,” said John Cain, American Rivers Director of Conservation for California Flood Management. 

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Fremont Weir photos and video are available for download.



Niki Woodard, Public Affairs Office, Department of Water Resources

916-653-4161 |


Erin Curtis, Public Affairs Office, Bureau of Reclamation

916-978-5101 |