Working Draft Scientific Basis Report for New and Revised Flow Requirements on the Sacramento River and Tributaries, Eastside Tributaries to the Delta, Delta Outflow, and Interior Delta Operations

California State Water Resources Control Board (SWRCB) | October 14th, 2016

This working draft Scientific Basis Report (Report) is being prepared to support the update of the Bay-Delta Plan’s protection of fish and wildlife beneficial uses in t

This working draft Scientific Basis Report (Report) is being prepared to support the update of the Bay-Delta Plan’s protection of fish and wildlife beneficial uses in the Sacramento River watershed and related areas, known as Phase II.1 This update considers four categories of requirements: (1) new inflow requirements for the Sacramento River, its tributaries, and eastside tributaries to the Delta; (2) changes to Delta outflow requirements; (3) new and modified interior Delta flow requirements; and (4) new requirements for cold water habitat. A comprehensive regulatory approach is needed that protects Bay-Delta fish and wildlife throughout their migratory range, and that better integrates the regulatory framework addressing inflows, outflows, and water project operations. Such a framework will help avoid overreliance on one stream to meet flow and other water quality requirements by providing necessary flows on multiple tributaries to ensure suitable habitat and migratory pathways upstream of the Bay-Delta. Another goal is to employ a strategy that provides for timely action, flexibility, and integration with other planning, science, restoration, and regulatory efforts so action can be taken before imperiled species in the watershed are no longer able to be restored.

Yolo Bypass Salmon Habitat Restoration and Fish Passage Analytical Tool Review

Delta Stewardship Council (Delta Council) | October 1st, 2017

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operat

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operations of the Central Valley Project (CVP) and State Water Project (SWP) that includes Reasonable and Prudent Alternatives (RPA) designed to alleviate jeopardy to listed species and adverse modification of critical habitat. NMFS’ RPA requires the U.S. Bureau of Reclamation (Reclamation) to increase juvenile flood plain rearing habitat and improve adult fish passage for ESA-listed salmonids and sturgeon. The BiOp requires seventy-three (73) habitat restoration actions, five of which are specific to the Yolo Bypass. The California Department of Water Resources (DWR) and Reclamation have developed project alternatives for the Draft Yolo Bypass Fish Passage and Habitat Restoration EIS/EIR focused on the following two Yolo Bypass actions, which are the subject of this review:  - Increase seasonal floodplain inundation in the lower Sacramento River Basin  - Improve fish passage throughout the Yolo Bypass Alternatives The alternatives developed to address these two actions consist of a notch in the Fremont Weir, with alternative locations and configurations (width and weir-crest elevations), designed to increase the frequency and duration of hydraulic connectivity between the main-stem Sacramento River and the Yolo Bypass and to improve fish passage. Six alternative locations / configurations for a notch were identified.

Yuba-Feather FIRO Final Viability Assessment

California Department of Water Resources (DWR) | March 14th, 2025

This Yuba-Feather Final Viability Assessment (FVA) evaluates whether improved precipitation and runoff forecasts can reduce flood risk downstream of New Bullards Bar (NBB

This Yuba-Feather Final Viability Assessment (FVA) evaluates whether improved precipitation and runoff forecasts can reduce flood risk downstream of New Bullards Bar (NBB), owned and operated by Yuba Water Agency (Yuba Water), and Lake Oroville (ORO), owned and operated by the California Department of Water Resources (DWR). These reservoirs are in the Yuba-Feather watersheds in the Sierra Nevada and eastern Sacramento Valley of Northern California (Figure ES-1 and ES-2). Each reservoirs’ flood risk reduction operations are regulated by United States Army Corps of Engineers (USACE) through Water Control Manuals (WCMs).  Reducing flood risk by making reservoir releases ahead of storms creates additional temporary flood storage space for anticipated inflows but requires confidence and skill in forecasted conditions.