Sacramento River

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

Corning Subbasin Groundwater Sustainability Plan

Tehama County Flood Control and Water Conservation District | December 20th, 2021

Preparation of this GSP is the first step for the GSAs to achieve groundwater sustainability in the Corning Subbasin. To evaluate progress toward groundwater sustainabili

Preparation of this GSP is the first step for the GSAs to achieve groundwater sustainability in the Corning Subbasin. To evaluate progress toward groundwater sustainability during implementation, annual reports and 5-year updates to the GSP will be prepared as required by SGMA. The GSAs recognize that sustainability is only possible with support of stakeholders and coordination of local, state, tribal and federal agencies and the managed use of both surface and groundwater resources. While SGMA does not require the Plan to address California’s Public Trust Doctrine, a 2018 California Court of Appeal ruling found that groundwater pumping that reduces the flow or volume of water in a navigable stream (and tributaries that supply navigable streams) may violate the public trust. This Plan recognizes the importance of protecting public trust resources, including fish and wildlife, in the Subbasin’s streams that are connected to groundwater.

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

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

Cultivating climate resilience in California agriculture: Adaptations to an increasingly volatile water future

National Academy of Sciences (NAS) | July 29th, 2024

CV SALTS Prioritization & Optimization Study Year 1 Progress Report

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | March 24th, 2023