Department of Water Resources Home

Yolo Bypass


sutter bypass

Environmental Services

Dean Messer, Chief

3500 Industrial Blvd.
West Sacramento, CA 95691
(916) 376-9699

Mailing Address:
P.O. Box 942836
Sacramento, CA 94236-0001



Yolo Bypass Links

Fremont Weir Adult Fish Passage Modification Project

photo of fremont weir Existing fish ladder in Fremont Weir. Photo Credit: E. Olin


The only way for adult fish migrating through the Yolo Bypass to get back to the Sacramento River is to swim over the top of Fremont Weir during an overtopping event, which in some years never occurs. As the water recedes after an overtopping event, fish must use the fish ladder, a small structure in the middle of the two-mile long weir. This project will widen and deepen the fish passage structure, which will allow migratory adult fish to more readily find the structure and more effectively re-enter the Sacramento River.

Other potential barriers for migratory fish take the form of agricultural road crossings through the Tule Canal in the northern Yolo Bypass. To allow for clear passage of migratory fish at these crossings, this project also includes removing one road crossing that is no longer used and replacing one crossing with a fish-friendly culvert structure.

DWR and Reclamation are working closely with landowners to ensure the project’s goals are met and current agricultural practices may continue. Completion of this project will help fulfill NMFS BO RPA Action I.7.

Next Steps


Construction is anticipated to begin in late 2017 or May 2018.

Planning and Design Status

DWR and Reclamation prepared the draft Initial Study/Environmental Assessment (IS/EA) and proposed Mitigated Negative Declaration (MND) for the Fremont Weir Adult Fish Passage Modification Project in accordance with the California Environmental Quality Act and the National Environmental Policy Act.

The draft IS/EA and proposed MND (State Clearinghouse Number 201702212) was circulated for public review and comment from February 3 through March 6, 2017. DWR and Reclamation recirculated the Biological Resources portion (Section 3.5) of the draft IS/EA for public review and comment from May 15 through June 13, 2017. Changes to the draft IS/EA are indicated by underline for new text and strikethrough for deleted text. To view public comments and responses to comments, please refer to Appendices H and I.

On August 17, 2017, DWR certified the Final IS/EA and submitted a Notice of Determination (PDF) to the State Clearinghouse. The Final IS/EA is also available at Reclamation's website and Reclamation's Yolo Bypass webpage. A printed copy is available to view during business hours (8 a.m. to 5 p.m.) at the DWR office located at 3500 Industrial Blvd. in West Sacramento and Reclamation’s Bay-Delta Office at 801 I St., Suite 140, in Sacramento.

DWR and Reclamation are in the process of obtaining all federal, state, and local permits and approvals for the project. Permitting is anticipated to be completed in 2017.

For further information, please contact Karen Enstrom at (916) 376-9778 or or Ben Nelson at (916) 414-2424 (TTY 800-877-8339) or

Access the environmental document below: