Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project EIS/EIR

Existing conditions model output

Existing conditions model output

The Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project is a collaboration between the Bureau of Reclamation and California Department of Water Resources, that aims to provide seasonal inundation that mimics the natural process of the floodplain and improves connectivity within the Yolo Bypass and to the Sacramento River.

cbec is providing the agency’s respective consultants with engineering services in fulfillment of the Environmental Impact Statement (EIS) and Environmental Impact Report (EIR). This EIS/EIR aims to develop a preferred alternative to meet the Reasonable and Prudent Alternative actions set forth in the National Marine Fisheries Service’s Biological Opinion for creating floodplain habitat for juvenile salmonids (Chinook salmon, Central Valley steelhead, and green sturgeon) and improving fish passage within the Yolo Bypass.

To support the evaluation of multiple alternatives to meet fish passage and habitat inundation cbec (working with HDR, Inc.,) developed a detailed 1D/2D hydrodynamic TUFLOW Classic model for the Yolo Bypass and vicinity. The efficacy of multiple alternatives were evaluated over a 16-year simulation period, and the hydrodynamic outcomes were also used to inform subsequent agricultural economic impact and fish benefits analyses. Project activities included conducting topographic and bathymetric surveys of numerous channel and floodplain features within the Yolo Bypass. Existing topographic and vegetation information was thoroughly reviewed, additional surveys performed, long-term boundary conditions prepared, and alternatives configured. Post-processing tools were also developed for examining the model outputs and providing formatted information to other technical teams. Multiple analysis were conducted, including; inundation analysis, flood impacts analysis, water temperature analysis, sedimentation and erosion analysis, water allocation analysis, and groundwater impact analysis. Furthermore, wind-wave analysis assessed potential impacts of wind-waves against the Yolo Bypass levees (as a consequence of adjustments to a weir that was designed to accommodate periods of high flow in the Sacramento River).

The Final Environmental Impact Statement/Environmental Impact Report (EIS/EIR) was approved in 2019. After conclusion of the CEQA/NEPA process, the project will move forward with design, permitting, and real estate right-of-way acquisitions.

Waterbody / Watershed

Sacramento River, Prospect Slough, Putah Creek, Willow Slough