Delta eLibrary

REPORTS

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.

Tule Canal Charrette Outcomes (June 2021). Yolo County facilitated a two-day virtual workshop/planning charrette to bring diverse stakeholders together to develop a shared vision for the Tule Canal within the Yolo Bypass. Prepared as the final component of the December 2020 Yolo Bypass Drainage and Water Infrastructure Improvement Study Update, the workshop included 71 participants including farmers, policy makers, landowners, hunters, conservation scientists, educators, engineers, and ecologists. The outcomes included support for three actions: a multi-functional Tule Canal, a Yolo Bypass strategic plan, and a Yolo Bypass governing entity. The vision synthesized from the contributions of the 10 workgroups is as follows: “We envision a transformed Tule Canal as an integrated corridor, which engages people, sustains farmers, protects property, and provides diverse wildlife habitat.” (Executive Summary)
Yolo Bypass Drainage and Water Infrastructure Improvement Study Update (December 2020). Yolo County prepared this Yolo Bypass Drainage and Water Infrastructure Improvement Study Update (Study Update) to identify specific drainage and water infrastructure improvements within and directly adjacent to the Yolo Bypass that would benefit farmers and wetland managers. This study builds off of the original Yolo Bypass Drainage and Water Infrastructure Improvement Study that the County prepared in 2014 (2014 Study). The Study Update identifies twelve specific drainage and water infrastructure improvements or project concepts that were identified through a series of interviews with local stakeholders (i.e., growers, landowners, and local organizations with an interest in the Yolo Bypass) and were refined from a list of 91 preliminary project concepts. The twelve project concepts were selected based on the benefits they would provide, their readiness to be constructed, the potential for local matching funds, their eligibility for state and federal funding, their costs, and whether they have a local sponsor or champion.
Yolo County Datasharing Proposal (March 2020). Yolo County partnered with the San Francisco Estuary Institute to develop a proposal to consolidate and share data related to the Yolo Bypass. Funded by the California Department of Fish and Wildlife as part of the Yolo Bypass Westside Tributaries Flow Monitoring Project, the proposal outlines recommendations for a centralized data portal, provides cost estimates, and includes an initial list of potential Yolo Bypass data sources. The proposal will serve as the foundation for a future grant application to develop the portal.
Yolo Bypass Westside Tributaries Flow Monitoring Report (March 2020). The Yolo Bypass Westside Tributaries Flow Report is the result of Yolo County’s work in coordination with cbec ecoengineering to collect and analyze flow and stage data on four westside tributaries to the Yolo Bypass: Knights Landing Ridge Cut, Cache Creek Settling Basin, Willow Slough Bypass, and Putah Creek. Funded by a California Department of Fish and Wildlife grant, the new data will improve westside tributary inflow estimates into the Yolo Bypass, as well as westside tributary hydrologic assumptions used in the Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project (Yolo Bypass Salmonid Project) inundation analysis (USBR and DWR, 2019) . The new data also can improve local agency reporting of Yolo Bypass inflows, help decisionmakers better understand existing conditions, and inform evaluations of the benefits and impacts of future management proposals within the Yolo Bypass.
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.
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.
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.
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.
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.
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.
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.
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.

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:

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.

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