Aquatic Ecosystem Stressors in the Sacramento-San Joaquin Delta

Public Policy Institute of California (PPIC) | May 5th, 2012

This report presents results from an analysis of the institutional and legal options for more effective ecosystem management in the Sacramento-San Joaquin Delta. It is pa

This report presents results from an analysis of the institutional and legal options for more effective ecosystem management in the Sacramento-San Joaquin Delta. It is part of a wide-ranging study on the management of multiple ecosystem stressors in the Delta. .

Aquatic Life Study Final Report

San Joaquin Valley Drainage Authority | January 6th, 2016

Central Valley Salinity Alternatives for Long Term Sustainability (CV‐SALTS) is developing a comprehensive regulatory and programmatic approach to the management of sa

Central Valley Salinity Alternatives for Long Term Sustainability (CV‐SALTS) is developing a comprehensive regulatory and programmatic approach to the management of salt and nitrate in the Central Valley that is consistent with the State Recycled Water Policy (SRWP). This work is being carried out collaboratively with the Central Valley Regional Water Quality Control Board (Central Valley Water Board), the State Water Resources Control Board (State Water Board), the Central Valley Salinity Coalition and Stakeholders. As stated in the CV‐SALTS Strategy and Framework document, the strategy to fulfill the requirements of the SRWP is to adopt a Central Valley Salt and Nitrate Management Plan (SNMP) and revise the Basin Plans applicable to the Central Valley to facilitate implementation of the SNMP. This effort includes a technical review of the state of science with regards to the establishment of appropriate water quality objectives (WQO) to protect surface water beneficial uses. This Aquatic Life Study was undertaken to evaluate the technical basis for the establishment of salinity‐related WQOs to protect aquatic life in the Central Valley. The findings of this analysis will be considered by CV‐SALTS during development and adoption of the SNMP.

Assessing Regional Strategies to Cope with Drought, Climate, and Environmental Flow Policy Impacts for a Sustainable Water Supply: A Case Study of the Bay Area

American Chemical Society (ACS) | December 27th, 2024

Assessing Spatial Variability of Nutrients, Phytoplankton, and Related Water-Quality Constituents in the California Sacramento–San Joaquin Delta at the Landscape Scale: Comparison of Four (2018, 2020, 2021, 2022) Spring High-Resolution Mapping Surveys

U.S. Geological Survey (USGS) | July 2nd, 2025

This report summarizes results from boat-based, high-resolution water-quality mapping surveys completed before, during, and after upgrades to the EchoWater Resource Recov

This report summarizes results from boat-based, high-resolution water-quality mapping surveys completed before, during, and after upgrades to the EchoWater Resource Recovery Facility (EchoWater Facility), the regional wastewater facility for the City of Sacramento and surrounding areas, near Elk Grove, California. Surveys were completed in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) in spring (May or June) 2018, 2020, 2021, and 2022. In each survey, a suite of in situ sensors were used to continuously (one measurement per second) measure water-quality conditions, nutrients, phytoplankton abundance, and species composition. In addition to in situ data collection, discrete water samples were collected about every 2 miles while underway for determination of phosphate, ammonium, and nitrate concentration.

Assessing the Impact of Periodic Dredging on Macroinvertebrate Prey Availability for Benthic Foraging Fishes

U.S. Geological Survey (USGS) | July 1st, 2017

Due to its importance for special status fish, the San Francisco Bay (SFB) estuary has been designated as Essential Fish Habitat (EFH) under the Magnuson-Stevens Fishery

Due to its importance for special status fish, the San Francisco Bay (SFB) estuary has been designated as Essential Fish Habitat (EFH) under the Magnuson-Stevens Fishery Conservation and Management Act ([MSA; 16 U.S.C. 18559b)]. Within this estuary, benthic macroinvertebrate communities provide important prey resources for many economically significant fish species that rely on EFH. Periodic maintenance dredging can impact these infaunal communities; however, there is a lack of scientific information specific to SFB on the degree of benthic community disruption caused by dredging. In addition, rates of benthic community recolonization and recovery following dredging and subsequent effects on foraging fish are unknown. For this reason, it is difficult for regulatory and resource agencies to determine the impacts of maintenance dredging. Thus, the National Marine Fisheries Service (NMFS) and the consortium of agencies (US Environmental Protection Agency (EPA), US Army Corp of Engineers (USACE), San Francisco Regional Water Quality Control Board (SFRWQCB), and San Francisco Bay Conservation and Development Commission (BCDC)) comprising the San Francisco Bay Long Term Management Strategy for Dredging (LTMS) effort identified a study of dredging impacts on SFB fish foraging habitat as one of their highest priorities in their 2011 Programmatic EFH Agreement. 

Assessment of Nutrient Status and Trends in the Delta in 2001–2016: Effects of drought on ambient concentrations and trends

San Francisco Estuary Institute (SFEI) | March 1st, 2018

Nutrients and the effects of nutrients on water quality in the Sacramento-San Joaquin Delta is a priority focus area for the Delta Regional Monitoring Program (Delta RMP)

Nutrients and the effects of nutrients on water quality in the Sacramento-San Joaquin Delta is a priority focus area for the Delta Regional Monitoring Program (Delta RMP). The Program’s first assessment question regarding nutrients is: “How do concentrations of nutrients (and nutrient-associated parameters) vary spatially and temporally?” In this analysis, we confirmed previously reported declining trends in the San Joaquin River for nutrient concentrations at Vernalis and chlorophyll-a concentrations at Buckley Cove and Disappointment Slough. A slight increasing trend for dissolved oxygen at Buckley Cove was also detected which could be confirmation that management actions for the San Joaquin River Dissolved Control Program are having the desired effect. Finally, at stations in Suisun Bay, the Confluence region, and Franks Tract, chlorophyll-a showed modest increasing trends, which were not evident in previous analyses. The new analyses presented in this report and the findings from earlier reports constitute encouraging early progress toward answering the Delta RMP’s assessment questions. Specifically, due to the existence of long-term data sets and synthesis efforts, spatial and temporal trends in the concentrations of nutrients and nutrient-related parameters are reasonably well understood and so are the magnitudes of the most important sources of nutrients from outside the Delta. However, additional synthesis work could be done to understand the factors behind these trends. Large knowledge gaps remain about nutrient sinks, sources, and processes within the Delta. The mechanistic, water quality-hydrodynamic models being developed for the Delta may be able to address these questions in the future.

Authority and Effectiveness of the State Water Resources Control Board

Delta Vision Blue Ribbon Task Force (Delta Vision) | July 1st, 2008

This report addresses issues related to the effectiveness of the California State Water Resources Control Board (“State Board” or “Board”) in carrying out its rol

This report addresses issues related to the effectiveness of the California State Water Resources Control Board (“State Board” or “Board”) in carrying out its roles and responsibilities, with particular reference to the Sacramento-San Joaquin San Francisco Bay-Delta (“Delta”). Section 1 presents an overview and evaluation of the authority and responsibility of the State Board. Section 2 describes actions of the State Board over many years in connection with the Delta, and in summary form, the Mono Lake basin and the Yuba River. Based on the preceding sections, Section 3 evaluates the effectiveness of the Board with particular reference to the Delta and sets forth some observations related to the Board’s authority and effectiveness.

Availability of high-magnitude streamflow for groundwater banking in the Central Valley, California

Environmental Research Letters (IOP) | July 31st, 2017

California’s climate is characterized by the largest precipitation and streamflow variability observed within the conterminous US This, combined with chronic gr

California’s climate is characterized by the largest precipitation and streamflow variability observed within the conterminous US This, combined with chronic groundwater overdraft of 0.6–3.5 km3 yr 1, creates the need to identify additional surface water sources available for groundwater recharge using methods such as agricultural groundwater banking, aquifer storage and recovery, and spreading basins. High-magnitude streamflow, i.e. flow above the 90th percentile, that exceeds environmental flow requirements and current surface water allocations under California water rights, could be a viable source of surface water for groundwater banking. Here, we present a comprehensive analysis of the magnitude, frequency, duration and timing of high-magnitude streamflow (HMF) for 93 stream gauges covering the Sacramento, San Joaquin and Tulare basins in California. The results show that in an average year with HMF approximately 3.2 km3 of high-magnitude flow is exported from the entire Central Valley to the Sacramento-San Joaquin Delta often at times when environmental flow requirements of the Delta and major rivers are exceeded. High-magnitude flow occurs, on average, during 7 and 4.7 out of 10 years in the Sacramento River and the San Joaquin-Tulare Basins, respectively, from just a few storm events (5–7 1-day peak events) lasting for 25–30 days between November and April. The results suggest that there is sufficient unmanaged surface water physically available to mitigate long-term groundwater overdraft in the Central Valley.

Background and Recent History of Water Transfers in California

California Department of Water Resources (DWR) | July 1st, 2015

The purpose of this paper is to provide a basic understanding of water transfers in California with an emphasis on transfers that move water through the Sacramento-

The purpose of this paper is to provide a basic understanding of water transfers in California with an emphasis on transfers that move water through the Sacramento-San Joaquin Delta (Delta). This paper provides an overview of various types of water transfers, their recent history, and the regulatory setting that governs transfers. In its 1976 report, the Governor’s Commission on Water Rights recognized the importance of water transfers to the future of California’s water supply and made recommendations regarding the need for specific changes to the Water Code to facilitate the transfer of water. Many of these changes were accomplished in the following years and are reflected in the discussions below. Water transfers involve a change in the place of water use, from the water’s historic point of diversion and use, to a new location either within or outside the watershed of origin. Water may be transferred from one user to another for a variety of purposes, including agricultural, municipal and industrial uses. It may also be transferred for environmental purposes such as in-stream flow augmentation and wildlife refuges. Water transfers and exchanges can be temporary (up to one year) or long-term (more than one year, but not permanent) or permanent. Water transfers can be an effective water management tool providing much-needed flexibility in the allocation and use of water in California. Transfers in California are primarily executed to meet dry-year demands rather than to obtain a primary water supply for either agricultural or municipal development. Transfers are particularly useful for meeting critical needs during drought periods. Transfers, however, must be carried out in a responsible manner in order to assure that they do not result in adverse impacts to other water users or unreasonable effects to the environment.

Battling the Inland Sea

University of California Press | July 1st, 1998