San Joaquin River

Conjunctive Water Management Resource Management Strategy

California Department of Water Resources (DWR) | April 29th, 2024

Conjunctive water management, also referred to as conjunctive use, is broadly defined as the coordinated and planned use and management of the different sources of water

Conjunctive water management, also referred to as conjunctive use, is broadly defined as the coordinated and planned use and management of the different sources of water in time and space. It is usually focused on surface water and groundwater resources to maximize the availability and reliability of water supplies in a region to meet various management objectives. It is a holistic approach to water resource management that can increase available water for beneficial uses, allow water agencies greater flexibility in scheduling deliveries, and improve drought resiliency (California Department of Water Resources 2003).

Conservation Strategy for Restoration of the Sacramento-San Joaquin Delta, Sacramento Valley and San Joaquin Valley Regions

CALFED | May 15th, 2014

The Conservation Strategy describes ERP goals and conservation priorities for Stage 2 of the CALFED Bay-Delta Program (CALFED) and was developed by the Department of Fish

The Conservation Strategy describes ERP goals and conservation priorities for Stage 2 of the CALFED Bay-Delta Program (CALFED) and was developed by the Department of Fish and Wildlife (CDFW) in coordination with the United States Fish and Wildlife Service (USFWS) and the National Oceanic and Atmospheric Administration Fisheries Service (NOAA Fisheries), collectively known as the ERP Implementing Agencies. This document serves as the conceptual framework that will guide future ERP environmental restoration, including development of conservation priorities and processes to identify and implement restoration opportunities, and monitoring to guide and improve its success in the Sacramento-San Joaquin Delta (Delta), and the Sacramento Valley and the San Joaquin Valley regions. This Conservation Strategy builds on information presented in the Ecosystem Restoration Program Plan (ERPP) (CALFED 2000a), the Multi-species Conservation Strategy (MSCS) (CALFED 2000d), ERP Milestones Reports (CALFED 2001b) and Annual Reports (DFG 2011b), the best available science on current ecological conditions, related programs and planning efforts, and input from stakeholders and the general public. There are many different kinds of conservation planning currently underway for the Delta, Sacramento and San Joaquin Valley regions and restoration is very much a shared vision between and among the agencies, various resource users, and the public. ERP Implementing Agencies will be using this ERP Stage 2 Conservation Strategy as a guide through the end of Stage 2 (2030). It provides a comprehensive ecosystem restoration strategy for ERP efforts in the Focus Area (Focus Area) (Figure 1), allowing flexibility in adapting responses accordingly to new scientific findings, changed circumstances and new or modified future conservation priorities. This Conservation Strategy will serve as a guide to identify programmatic-level types and locations of potential restoration actions based on conservation priorities. It is not a prescription for restoration actions at any specific site. Within this strategy is a compilation of conservation priorities, articulated from lessons learned during Stage 1, which may be used to meet ERP goals. All agencies, groups, or individuals interested in resource conservation and management within the Focus Area are encouraged to use this document as a guide to help coordinate activities to address ERP conservation priorities.

Contaminant Effects on California Bay-Delta Species & Human Health

University of California, Davis (UC Davis) | December 1st, 2016

Many contaminants in the California Bay-Delta exceed regulatory standards, impact aquatic species, and potentially affect human health. Recent studies provide evidence th

Many contaminants in the California Bay-Delta exceed regulatory standards, impact aquatic species, and potentially affect human health. Recent studies provide evidence that contaminants impact species of concern in the Bay-Delta (e.g., the decline of several important fish species referred to as the “Pelagic Organism Decline”). Multiple chemicals impair processes at cellular and physiological levels (measured as growth, development, and behavior abnormalities), ultimately affecting populations. As an important example, the population decline of the endangered delta smelt (Hypomesus transpacificus) is significantly associated with multiple stressors, including insecticide use. New analyses presented in this paper show significant correlations between pyrethroid (an insecticide) use and declining abundance of POD fish species. Water sampled from the Bay-Delta causes multiple harmful effects in fish and delta smelt. Fish prey items are also impacted by contaminants; this may have an indirect effect on their populations. Co-occurrence with thermal changes or disease can worsen contaminant effects. Contaminants also pose threats to human health via consumption of fish, drinking water, and contact recreation, in particular, mercury, toxins, disinfection byproducts, pesticides, pharmaceuticals, and personal care products. The role of contaminants in the decline of Bay-Delta species is difficult to accurately assess in a complex, dynamic system. However, tools and approaches are available to evaluate contaminant impacts on Bay-Delta species, and separate the effects of multiple stressors. Integrated monitoring and focused mechanistic studies are instrumental for addressing management needs. Impact and risk assessments should be conducted for different species across multiple life stages, with emphasis on early life stages of high-priority Bay-Delta species.  

Contributions of Climate Change and ENSO Variability to Future Precipitation Extremes Over California

American Geophysical Union (AGU) | June 14th, 2023

Coordinated Long-Term Operation of the Central Valley Project and State Water Project, Final Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | November 30th, 2015

Costs of Ecosystem Management Actions for the Sacramento-San Joaquin Delta

Public Policy Institute of California (PPIC) | April 22nd, 2013

California is at a critical juncture on policy for the Sacramento–San Joaquin Delta. This report summarizes the results of a wide-ranging study of cost-effective wa

California is at a critical juncture on policy for the Sacramento–San Joaquin Delta. This report summarizes the results of a wide-ranging study of cost-effective ways to improve the health of the Delta ecosystem. It highlights the need for science-based, integrated management of the many sources of ecosystem stress. The report also recommends improvements to the highly fragmented system of oversight that now involves dozens of federal, state, and local agencies. Several companion reports contain related findings: Aquatic Ecosystem Stressors in the Sacramento–San Joaquin Delta (Mount et al. 2012) summarizes the science of Delta ecosystem stressors for a policymaking audience. Integrated Management of Delta Stressors: Institutional and Legal Options (Gray et al. 2013) lays out proposals for institutional reform of science, management, and regulation. Scientist and Stakeholder Views on the Delta Ecosystem (Hanak et al. 2013) presents detailed results of the two surveys conducted by the report’s authors. Stress Relief: Prescriptions for a Healthier Delta Ecosystem (Hanak et al. 2013) summarizes the overall research project and the recommendations it generated. Where the Wild Things Aren’t: Making the Delta a Better Place for Native Species (Moyle et al. 2012) outlines a realistic long-term vision for achieving a healthier ecosystem.

Counties Wresting Control: Local Responses to California's Statewide Water Market

University of Denver Water Law Review (UDWLR) | January 1st, 2003

Cover cropping and no-tillage improve soil health in an arid irrigated cropping system in California’s San Joaquin Valley, USA

Soil and Tillage Research (Elsevier) | January 3rd, 2017

The concept of soil health has attracted considerable attention during the past two decades, but few studies have focused on the effects on soil health of long-term soil

The concept of soil health has attracted considerable attention during the past two decades, but few studies have focused on the effects on soil health of long-term soil management in arid irrigated environments. We investigated the effects of cover cropping and no-till management on soil physical and chemical properties during a 15-year experiment in California’s San Joaquin Valley (SJV) USA. Our objective was to determine if soil health could be improved by these practices in an annual crop rotation. The impact of long-term no-tillage (NT) and cover cropping (CC) practices, alone and in combination, was measured and compared with standard tillage (ST) with and without cover crops (NO) in irrigated row crops after 15 years of management. Soil aggregation, rates of water infiltration, content of carbon, nitrogen, water extractable organic carbon (WEOC) and organic nitrogen (WEON), residue cover, and biological activity were all increased by NT and CC practices relative to STNO. However, effects varied by depth with NT increasing soil bulk density by 12% in the 0–15 cm depth and 10% in the 15–30 cm depth. Higher levels of WEOC were found in the CC surface (0–5 cm) depth in both spring and fall samplings in 2014. Surface layer (0–15 cm) WEON was higher in the CC systems for both samplings. Tillage did not affect WEON in the spring, but WEON was increased in the NT surface soil layer in the fall. Sampling depth, CC, and tillage affected 1-day soil respiration and a soil health index assessment, however the effects were seasonal, with higher levels found in the fall sampling than in the spring. Both respiration and the soil health index were increased by CC with higher levels found in the 0–5 cm depth than in the 5–15 and 15–30 cm depths. Results indicated that adoption of NT and CC in arid, irrigated cropping systems could benefit soil health by improving chemical, physical, and biological indicators of soil functions while maintaining similar crop yields as the ST system.

Critical Aquifer Overdraft Accelerates Degradation of Groundwater Quality in California's Central Valley During Drought

American Geophysical Union (AGU) | September 1st, 2021

It has been established that wells are at risk to run dry when groundwater levels decline during drought, but associated impacts to water quality are poorly understood. 

It has been established that wells are at risk to run dry when groundwater levels decline during drought, but associated impacts to water quality are poorly understood. This study examined 30 yr of data from California's Central Valley to find dramatic groundwater-level declines during drought were associated with worsening groundwater quality. This likely happens because increased pumping during drought can draw shallow, contaminated groundwater to depths commonly tapped by public drinking water wells. This is the first study of its kind to show direct linkages between drought and groundwater quality at such a broad spatial scale

Critical Assessment of the Delta Smelt Population in the San Francisco Estuary, California

University of California, Davis (UC Davis) | July 1st, 2005