San Joaquin River

First Supplement to Bulletin No. 11, San Joaquin County Investigation, Basic Data, Calaveras and Littlejohns Units, 1953-1955

California State Water Resources Control Board (SWRCB) | June 30th, 1955

Fish Bulletin 133. Ecological Studies of The Sacramento-San Joaquin Estuary Part 1: Zooplankton, Zoobenthos, and Fishes of San Pablo and Suisun Bays, Zooplankton and Zoobenthos of the Delta

California Department of Fish and Wildlife (CDFW) | September 9th, 1965

The Sacramento and San Joaquin Rivers have a common estuary. These two streams meet in the center of California's central valley to form the Delta (Figure 1). A hundred y

The Sacramento and San Joaquin Rivers have a common estuary. These two streams meet in the center of California's central valley to form the Delta (Figure 1). A hundred years ago the Delta was an extensive tidal marsh, but it has been almost entirely reclaimed for agriculture. The Delta now includes about 738,000 acres of land and water, 700 miles of navigable channels, and 30 large, below sea level islands. About 39,000 acres are covered by water. Some Delta channels are edged with narrow stretches of intertidal marsh but most of them have steep banks of mud or are covered with large cobbles to prevent erosion. They vary in width from a few hundred feet to a mile and are seldom more than 30 to 40 feet deep. In some areas there are small "waste" islands that flood during high tides. These waste islands and levees that surround all Delta channels are covered with an assortment of emergent aquatic plants, grasses, forbs, shrubs, and trees. Water heading toward the sea from the Delta passes through Suisun Bay, which is merely the wide combination of the Sacramento and San Joaquin Rivers below the Delta. Thirty-six percent of Suisun Bay is flooded by less than 3 feet of water at mean lower-low tide, and at this stage about 3,000 acres of intertidal zone is exposed. Richard Painter (see p. 40) has included a map of the 6-foot contour. From Suisun Bay the water flows through the 6-mile long and up to 100 feet deep Carquinez Strait into San Pablo Bay. Almost 60 percent of San Pablo Bay's 73,000 acres is less than 6 feet deep at mean lower-low tide. San Pablo Bay has a much more extensive intertidal area than Suisun Bay. San Pablo Bay water flows into San Francisco Bay and then through the narrow Golden Gate into the Pacific Ocean. The investigations reported on in this bulletin were geographically limited to the upper and middle portions of the estuary—from the Delta through San Pablo Bay. We have not investigated below San Pablo Bay. McCarty et al (1962) described south San Francisco Bay, and Storrs, Selleck, and Pearson (1964) described north San Francisco Bay. Gillian (1957) wrote an interesting and useful popular account of the entire bay.

Fish Collections and Secondary Louver Efficiency at the Tracy Fish Collection Facility: October 1993 to September 1995

U.S. Bureau of Reclamation (USBR) | May 29th, 1998

Fish Restoration Program Agreement Implementation Strategy for Habitat Restoration and Other Actions for Listed Delta Fish

California Department of Water Resources (DWR) | March 6th, 2012

The Fish Restoration Program Agreement (FRPA) (Appendix A), between the Department of Fish and Game (DFG) and the Department of Water Resources (DWR), was signed on Octob

The Fish Restoration Program Agreement (FRPA) (Appendix A), between the Department of Fish and Game (DFG) and the Department of Water Resources (DWR), was signed on October 18, 2010. FRPA addresses specific habitat restoration requirements of the US Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) biological opinions (Biological Opinions) for State Water Project (SWP) and Central Valley Project (CVP) operations. FRPA is also intended to address the habitat requirements of the DFG Longfin Smelt Incidental Take Permit (ITP) for SWP Delta operations. The primary objective of the FRPA program is to implement the fish habitat restoration requirements and related actions of the Biological Opinions and the ITP in the Delta, Suisun Marsh, and Yolo Bypass and is focused on 8,000 acres of intertidal and associated subtidal habitat to benefit delta smelt, including 800 acres of mesohaline habitat to benefit longfin smelt, and a number of related actions for salmonids. DFG and DWR intend that habitat restoration actions implemented in compliance with the USFWS biological opinion that also meet the habitat restoration requirements of the ITP will operate to satisfy the acreage requirements of the ITP. The purpose of this Implementation Strategy is to describe the process by which DWR and DFG will implement the FRPA program, and to satisfy Section B of FRPA. Section B of FRPA requires DWR, with assistance from DFG, to develop an Implementation Schedule that will identify restoration actions, estimated costs, targeted acreage, and a timeline for DWR’s implementation of restoration actions to satisfy DWR’s obligations under the Biological Opinions and ITP. Appendix B lists the specific habitat restoration requirements of FRPA, the Biological Opinions, and the ITP that pertain to this program. This document lays out the strategy to address these requirements. In addition, DWR and DFG will complete the necessary environmental compliance documents to implement site specific habitat restoration projects; this may include tiering from existing programmatic documents where appropriate. Pursuant to FRPA, DFG will work cooperatively with and assist DWR in establishing the management and financial framework necessary to implement the FRPA program. DWR, with assistance from DFG, will begin a process to fund, plan, and implement actions, including aquatic habitat restoration to benefit delta smelt, longfin smelt, and winter-run and spring-run Chinook salmon (hereafter referred to as Covered Fish Species) to mitigate impacts to these species caused by the SWP Delta operations. Specifically, these actions include: • Delta Smelt Biological Opinion Reasonable and Prudent Alternative (RPA) Component 4; • NMFS Biological Opinion RPA Actions 1.2.6 and 1.6.2 in partnership with the US Bureau of Reclamation (Reclamation); • NMFS Biological Opinion RPA Action Suite 1.6 and 1.7. FRPA will not be lead, but will provide funding and technical support assistance only; • ITP Condition 7. DWR’s obligations focus on delta smelt, longfin smelt, and winter-run and spring-run salmon, and may also benefit steelhead, sturgeon, and other native fish species.

Fish-Habitat Relationships Along the Estuarine Gradient of the Sacramento-San Joaquin Delta, California: Implications for Habitat Restoration

Estuaries and Coasts (Springer) | June 6th, 2018

Estuaries are highly variable environments where fish are subjected to a diverse suite of habitat features (e.g., water quality gradients, physical structure) that filt

Estuaries are highly variable environments where fish are subjected to a diverse suite of habitat features (e.g., water quality gradients, physical structure) that filter local assemblages from a broader, regional species pool. Tidal, climatological, and oceanographic phenomena drive water quality gradients and, ultimately, expose individuals to other habitat features (e.g., stationary physical or biological elements, such as bathymetry or vegetation). Relationships between fish abundances, water quality gradients, and other habitat features in the Sacramento-San Joaquin Delta were examined as a case example to learn how habitat features serve as filters to structure local assemblages in large river-dominated estuaries. Fish communities were sampled in four tidal lakes along the estuarine gradient during summer-fall 2010 and 2011 and relationships with habitat features explored using ordination and generalized linear mixed models (GLMMs). Based on ordination results, landscape-level gradients in salinity, turbidity, and elevation were associated with distinct fish assemblages among tidal lakes. Native fishes were associated with increased salinity and turbidity, and decreased elevation. Within tidal lakes, GLMM results demonstrated that submersed aquatic vegetation density was the dominant driver of individual fish species densities. Both native and non-native species were associated with submersed aquatic vegetation, although native and non-native fish populations only minimally overlapped. These results help to provide a framework for predicting fish species assemblages in novel or changing habitats as they indicate that species assemblages are driven by a combination of location within the estuarine gradient and site-specific habitat features.

Five Guiding Principles for Effective Voluntary Agreements

University of California, Berkeley (UC Berkeley) | January 3rd, 2024

California has increasingly emphasized efforts to develop voluntary agreements (VAs) with water users as a means of achieving regulatory goals in certain watersheds. In t

California has increasingly emphasized efforts to develop voluntary agreements (VAs) with water users as a means of achieving regulatory goals in certain watersheds. In theory, a VA can combine the protectiveness of a regulatory backstop with the creativity and flexibility of a negotiated deal to produce outcomes as good as, or better than, those achievable through strict application of regulatory requirements alone. However, reality has not always measured up to this ideal. This policy paper uses the Bay-Delta watershed as a case study to inform five principles to guide the appropriate use and evaluation of VAs.

Flood Risk and Management of California's Sacramento-San Joaquin Delta Levee System

University of California, Santa Cruz (UC Santa Cruz) | September 15th, 2020

Flood Size Increases Nonlinearly Across the Western United States in Response to Lower Snow-Precipitation Ratios

American Geophysical Union (AGU) | December 20th, 2019

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual snow fraction are projected under continued global warming, with potential impacts on flood risk. Here, we quantify the size of streamflow peaks in response to both seasonal and event-specific rain-fraction using stream gage observations from watersheds across the western United States. Across the study watersheds, the largest rainfall-driven streamflow peaks are >2.5 times the size of the largest snowmelt-driven peaks. Using a panel regression analysis of individual precipitation and snowmelt events, we show that the empirical streamflow response grows approximately exponentially as the liquid precipitation input increases, with rain-dominated runoff leading to proportionately larger streamflow increases than snowmelt or mixed rain-and-snow runoff. We find that the response to changes in rain percentage is largest in the wettest watersheds, where wet antecedent conditions are important for increasing runoff efficiency. Similarly, the effect of rain percentage is larger across watersheds in the Northwest and West regions compared to watersheds in the Northern Rockies and Southwest regions. Overall, as a higher percentage of precipitation falls as rain, increases in the size of rainfall-driven and “rain-on-snow”-driven floods have the potential to more than offset decreases in the size of snowmelt-driven floods.

Flood-MAR Research and Data Development Plan

California Department of Water Resources (DWR) | October 31st, 2019

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who wan

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who want to expand our collective knowledge about using floodwaters for managed aquifer recharge (Flood-MAR). This plan outlines the priority information needed by those making management decisions about the where, when, and how of capturing available flood water to replenish California’s depleted aquifers.

Flooded Wetland Availability for Breeding Waterfowl in a Mediterranean Climate: Mapping 38 Years of Historical Data in Suisun Marsh, California

University of California, Davis (UC Davis) | December 19th, 2025

Most managed wetlands in California are ephemeral and are purposefully flooded during the fall and winter for over-wintering waterfowl and are dry during the spring and s

Most managed wetlands in California are ephemeral and are purposefully flooded during the fall and winter for over-wintering waterfowl and are dry during the spring and summer waterfowl breeding season. Only semi-permanent and permanent wetlands remain flooded through the critical summer brood-rearing period for ducklings. We examined flooded wetland availability for breeding waterfowl in the brackish Suisun Marsh (California, USA) annually during the spring (April 27–May 17, during peak nesting) and summer (June 17–July 7, during peak duckling brood rearing), for a 38-year period using Landsat satellite imagery and spectral mixture analysis. Flooded wetland area increased 43% in spring and 48% in summer from 1984 to 2021 but varied among years (spring: 37.6–88.6 km2; summer: 17.7–57.5 km2). This increase in flooded wetland area over the past four decades was due to just a few sites, with only 24% (spring) and 15% (summer) of the 198 land-owner parcels increasing in flooded area. Flooded wetland area in the spring was unrelated to annual precipitation between October and April (range: 25–104 cm) or spring precipitation between January and April (range: 8-65 cm), whereas flooded wetland area in the summer was weakly correlated to both annual and spring precipitation. Flooded wetland area in spring and summer was also weakly correlated with the median daily outflow from the Sacramento-San Joaquin River Delta between March 15 and June 15, which corresponds to a critical period of wetland water management for breeding waterfowl. Our results indicate that spring and summer flooded wetland habitat for breeding waterfowl has slightly increased over the past four decades, varies annually, and is mostly dependent on local wetland management practices rather than on precipitation or Delta outflows. Managing habitats as semi-permanent wetlands would increase flooded wetland habitat in the spring and summer and provide habitat for nesting hens and ducklings.