The California Natural Resources Agency and the U.S. Department of the Interior propose to increase the frequency and duration of flooding in the Yolo Bypass for seasonal fish rearing habitat, both as a major component of the Bay Delta Conservation Plan and also as a Reasonable and Prudent Alternative in the federal National Marine Fisheries Service’s Biological Opinion on the Coordinated Long Term Water Operations of the Central Valley Project and State Water Project for winter run salmon, spring run salmon, and Central Valley steelhead. While the state and federal government have not yet fully defined proposals to flood the Bypass for juvenile salmon, the project will have broader support and cost less if state and federal agencies minimize effects on existing land uses such as flood protection, migratory waterfowl and other terrestrial species habitat, and agriculture. To assist with the efforts to minimize impacts, the Yolo County Board of Supervisors has commissioned the following studies related to Yolo Bypass inundation proposals. The studies are intended to guide efforts to develop a final project that provides significant fish benefits and minimizes impacts on existing land uses.
1. Agricultural and Economic Impacts of Yolo Bypass Fish Habitat Proposals (April 2013)
Yolo County worked with UC Davis researchers and the Yolo Basin Foundation to analyze the agricultural impacts of state and federal proposals to increase the frequency and duration of inundation in the Yolo Bypass to benefit juvenile salmon and other fish species.
2. Waterfowl Impacts of the Proposed Conservation Measure 2 for the Yolo Bypass – An effects analysis tool (July 2012)
Ducks Unlimited worked in cooperation with Yolo County and the Yolo Basin Foundation to analyze the potential impacts to waterfowl habitat of proposals to increase the frequency and duration of inundation in the Yolo Bypass to benefit juvenile salmon and other fish species.
3. Yolo Bypass MIKE-21 Model Review: Strengths, Limitations and Recommendations for Refinement (September 2012)
Yolo County worked with Northwest Hydraulics Consultants (NHC) to complete a review of the MIKE-21 model, used in the past to estimate the inundation footprint associated with proposals to increase the duration and frequency of Yolo Bypass inundation. This review applies to other models as well.
4. Yolo Bypass Drainage and Water Infrastructure Improvement Study (April 2014)
Yolo County worked with cbec eco engineering, Douglas Environmental, Consero Solutions, and the Yolo Basin Foundation to complete the Yolo Bypass Drainage and Water Infrastructure Improvement Study. The goal of the study was to work with Yolo Bypass and owners, farmers, and wetlands managers to identify and prioritize Yolo Bypass drainage and water infrastructure improvements that benefit agricultural and wetlands operations. The study will assist with the identification of improvements that could be implemented as part of any project to increase inundation in the Yolo Bypass for fish.
5. Yolo County Agricultural Economic Development Fund (October 2014)
The Yolo Ag Fund is a forward-looking effort to support the continued work of local growers to produce high-quality agricultural products and bring those products to the local, regional and national public. Yolo County developed the Yolo Ag Fund from existing plans approved by the Yolo County Board of Supervisors and in coordination with the Yolo County Ag Commissioner, the Yolo/Solano Farmbudsman, the Yolo County Farm Bureau, and other stakeholders working in local communities to promote agricultural sustainability. The Yolo County Agricultural Economic Development Fund (“Yolo Ag Fund”) is a central component of Yolo County’s efforts to support agricultural sustainability in the face of potential changes to the existing landscape of the county.
6. YOLO BYPASS SALMONID HABITAT RESTORATION AND FISH PASSAGE HYDRODYNAMIC MODELING DRAFT REPORT(February 2015) Yolo County contracted with the UC Davis Center for Watershed Sciences to review the hydrodynamic model developed to evaluate inundation from the proposed Yolo Bypass Salmonid Project. The Center found the choice of software is reasonable to produce a quality model application. The Center also concluded the model developed using the TUFLOW software in superior to other Yolo Bypass models produced in the past, such has MIKE-21. The Center identified a number of weakness and flaws with the model, however, which are detailed in the report.
7. POTENTIAL FISH BENEFITS ASSOCIATED WITH YOLO BYPASS SALMONID HABITAT RESTORATION AND FISH PASSAGE PROPOSALS (April 2017) This technical memorandum answers questions Yolo County posed in response to state and federal proposals to increase the frequency and duration of Yolo Bypass inundation as part of the Yolo Bypass Salmonid Habitat Restoration and Fish Passage project. The Salmonid Project is under development to address the Reasonable and Prudent Alternatives (RPA) I.6.1 and I.7 in the National Marine Fisheries Service’s (NMFS) Biological Opinion (BiOp) on the Coordinated Long Term Water Operations of the Central Valley Project (CVP) and State Water Project (SWP) for winter-run Chinook salmon, spring-run Chinook salmon, Central Valley steelhead and southern green sturgeon. The U.S. Bureau of Reclamation and the California Department of Water Resources are the lead agencies charged with implementation of the Salmonid Project, which contains two major elements: 1) a fish passage structure to replace the existing Fremont Weir fish ladder scheduled for construction in 2018; and 2) the construction of a structure in the Fremont Weir with operable gates to allow inundation of the Yolo Bypass for floodplain habitat, as well as additional fish passage structures, in 2021. Special emphasis was placed on reviewing potential benefits to target fish species from actions proposed in the EIS/EIR for the new operable gates.
8. Public Domain HEC-RAS Model with 2-D Floodplain of the Yolo Bypass and its Connection and Effects on the Sacramento River (May 2017). Yolo County helped fund a 1D/2D computerized hydraulic model of the Lower Sacramento River at the University of California, Davis Center for Watershed Sciences The work is an expansion of an earlier model focusing on the Yolo Bypass hydraulic dynamics and agricultural economic consequences (Suddeth 2014). The earlier project has been expanded to provide a public domain, fully capable hydraulic model of the Lower Sacramento River to assist with policy decisions. Updates include an improved digital elevation model (DEM) and implementation of newer features of the model software. The hydraulic model uses the software “HEC-RAS Version 5.0.0” developed by the U.S. Army Corps of Engineers Hydrologic Engineering Center.
BAY DELTA CONSERVATION PLAN COMMENTS
The Yolo County Board of Supervisors has submitted the following public comments on the Bay Delta Conservation Plan and the EIR/EIS:
- Comments on BDCP public draft (July 2014)
- Comments on BDCP EIR/EIS public draft (July 2014)
- Comments on BDCP administrative draft (September 2013)
- Comments on BDCP EIR/EIS (July 2013)
- Comments on BDCP EIR/EIS (April 2012)
YOLO COUNTY FLOOD GOVERNANCE STUDY
Yolo County Flood Governance Study, Prepared by UC Davis Extension Collaboration Center for the Westside Coordinating Committee & Project Delivery team. Funded by the Department of Water Resources and Administered by the City of West Sacramento.