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

Bay Area Green Infrastructure Water Quality Synthesis

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

San Francisco Bay is impacted by the numerous urban pollutants that flow from the surrounding landscape during storm events. In San Francisco Bay, total maximum daily lo

San Francisco Bay is impacted by the numerous urban pollutants that flow from the surrounding landscape during storm events. In San Francisco Bay, total maximum daily load (TMDL) clean-up plans are in place for polychlorinated biphenyls (PCBs) and mercury (Hg) (Davis et al., 2007; Davis et al., 2012). As municipalities strive to reach regulatory targets, green infrastructure (GI) presents a promising solution for managing stormwater pollutants while achieving additional environmental and social benefits. However, remaining data gaps including the best design layout, media composition, and vegetation and submerged zone effects on performance can prevent local managers from accurately assessing water quality benefits provided by green infrastructure as well as the maintenance needs to sustain adequate performance.

Bay Area Water Supply Resilience and the Bay-Delta Plan

Publisher not available | March 15th, 2024

Bay Delta Plan Phase 2 Workshop Summary Report

California State Water Resources Control Board (SWRCB) | January 1st, 2013

The California State Water Resources Control Board (Board) is tasked with updating the 2006 Water Quality Control Plan for the Bay-Delta Estuary (Bay-Delta Plan). The Boa

The California State Water Resources Control Board (Board) is tasked with updating the 2006 Water Quality Control Plan for the Bay-Delta Estuary (Bay-Delta Plan). The Board planning activities for this process have four phases. Phase 1 focused on San Joaquin River flow requirements and southern Delta water quality objectives. The current phase (Phase 2) focuses on fish and wildlife beneficial uses. Phase 3 will focus on modifications to water rights and Phase 4 will focus on the development and implementation of flow requirements for priority Delta tributaries. Phase 2 workshops were held to conduct discussions and generate information regarding the scientific and technical basis for considering potential changes to the Bay-Delta Plan. The workshops were informal; the Board did not take any official action and there was no sworn testimony. Information provided during the workshops will augment information developed through earlier reviews and will inform the Board members and staff on what, if any, changes should be made to the Bay-Delta Plan. Three workshops were held. Full workshop agendas are provided in Appendix A. 1. Ecosystem Changes and the Low Salinity Zone, September 5–6, 2012 – including the effects of the low salinity zone on various estuarine species, the interaction of salinity with non-flow related factors, and the identification of modeling or other tools that can be used to measure and reasonably protect estuarine habitat. 2. Bay-Delta Fishery Resources, October 1–2, 2012 – including flow, cold water pool, habitat, and water project operational constraints needed to reasonably protect Central Valley steelhead, Sacramento River winter-run, Central Valley late fall–run Chinook salmon, and pelagic species (including Delta smelt and longfin smelt); and the interaction of these issues with non-flow related factors. 3. Analytical Tools for Evaluating the Water Supply, Hydrodynamic, and Hydropower Effects of the Bay-Delta Plan, November 13–14, 2012 – including the CalSim II water supply model, DSM2 and RMA2 hydrodynamic models, Plexus hydropower model, and others as  applicable, together with results from applying these models to various scenarios.

Bay Delta Water Quality Control Plan (Bay Delta Plan)

California State Water Resources Control Board (SWRCB) | December 13th, 2006

"Bay Delta Plan" is short for the State Water Resources Control Board's (State Water Board) San Francisco Bay/Sacramento-San Joaquin Delta Estuary Water Quality Control P

"Bay Delta Plan" is short for the State Water Resources Control Board's (State Water Board) San Francisco Bay/Sacramento-San Joaquin Delta Estuary Water Quality Control Plan. The Bay-Delta Plan identifies the beneficial uses of the Bay-Delta, water quality objectives for the reasonable protection of those beneficial uses, and a program of implementation for achieving the objectives. The Bay-Delta Plan, when implemented, can determine the amount and timing of water entering and moving through the Delta. The State Water Board holds dual responsibilities of allocating surface water rights and protecting water quality. The State Water Board allocates water through an administrative system that is intended to maximize the beneficial uses of water while protecting the public trust, serving the public interest, and preventing the waste and unreasonable use or method of diversion of water. While most water quality control planning is done by the Regional Water Boards, the State Water Board has authority to adopt statewide water quality control plans. The State Water Board adopts the Bay-Delta Plan because of the Delta's importance as a major source of water supply for the state. The Bay-Delta Plan protects water quality in the region and includes water quality objectives to protect fish and wildlife beneficial uses through inflows to the Delta from the Sacramento and San Joaquin rivers and Delta outflows, in addition to objectives for salinity to protect agricultural beneficial uses. The State Water Resources Control Board (State Water Board) is in the process of a phased review and update of the 2006 Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary (Bay-Delta) (referred to as the 2006 Bay-Delta Plan). To learn more about the Bay-Delta Plan, click here. In 2009, the State Water Board began the process of reviewing and likely revising the 2006 Bay Delta Plan.  At the time of the archiving of this document, that update process still continues.  For the latest information, click here to visit the State Water Resources Control Board page for the Bay-Delta Plan Update.. RELATED DOCUMENT: Water Rights Decision 1641, the document that implements the 1995 Bay Delta Plan and is still in force.

Bed-Material Characteristics of the Sacramento–San Joaquin Delta, California, 2010–13

U.S. Geological Survey (USGS) | January 9th, 2017

The characteristics of bed material at selected sites within the Sacramento–San Joaquin Delta, California, during 2010–13 are described in a study conducted by the U.

The characteristics of bed material at selected sites within the Sacramento–San Joaquin Delta, California, during 2010–13 are described in a study conducted by the U.S. Geological Survey in cooperation with the Bureau of Reclamation. During 2010-13, six complete sets of samples were collected. Samples were initially collected at 30 sites; however, starting in 2012, samples were collected at 7 additional sites. These sites are generally collocated with an active streamgage. At all but one site, a separate bed-material sample was collected at three locations within the channel (left, right, and center). Bed-material samples were collected using either a US BMH–60 or a US BM–54 (for sites with higher stream velocity) cable-suspended, scoop sampler. Samples from each location were oven-dried and sieved. Bed material finer than 2 millimeters was subsampled using a sieving riffler and processed using a Beckman Coulter LS 13–320 laser diffraction particle-size analyzer. To determine the organic content of the bed material, the loss on ignition method was used for one subsample from each location. Particle-size distributions are presented as cumulative percent finer than a given size. Median and 90th-percentile particle size, and the percentage of subsample mass lost using the loss on ignition method for each sample are also presented in this report.

Benefit-Cost Analysis of the Delta Conveyance Project

Berkeley Research Group (BRG) | May 16th, 2024

This report presents the results of a benefit-cost analysis for the Delta Conveyance Project (DCP), a plan to modernize the State Water Project (SWP)’s conveyance infra

This report presents the results of a benefit-cost analysis for the Delta Conveyance Project (DCP), a plan to modernize the State Water Project (SWP)’s conveyance infrastructure in the Sacramento-San Joaquin River Delta (Delta). The SWP plays a crucial role in supplying water resources to 27 million Californians. Businesses in the area served by the SWP produce $2.3 trillion in goods and services annually, making it the world’s eighth-largest economy. The SWP delivers an average of 2.56 million acre-feet of water annually to urban and agricultural customers in the Bay Area, Central Valley, Central Coast, and Southern California. However, by 2070, climate change and sea-level rise are expected to reduce SWP deliveries by approximately 22%, or 546 thousand acre-feet per year (TAF/yr). In addition, the SWP faces an ongoing risk of service disruptions following seismic events near the Delta; these events could cause outages and reduce the quality of water exports from the SWP south of the Delta.

Bifenthrin, a ubiquitous contaminant, impairs the development and behavior of the threatened Longfin Smelt during early life stages

American Chemical Society (ACS) | June 23rd, 2023

The Longfin Smelt (Spirinchus thaleichthys) population in the San Franscisco Bay/Sacramento-San Joaquin Delta (Bay-Delta) has declined to ∼1% of its pre-1980s abundance

The Longfin Smelt (Spirinchus thaleichthys) population in the San Franscisco Bay/Sacramento-San Joaquin Delta (Bay-Delta) has declined to ∼1% of its pre-1980s abundance and, as a result, is listed as threatened under the California Endangered Species Act. The reasons for this decline are multiple and complex, including the impacts of contaminants. Because the spawning and rearing seasons of Longfin Smelt coincide with the rainy season, during which concentrations of contaminants increase due to runoff, we hypothesized that early life stages may be particularly affected by those contaminants. Bifenthrin, a pyrethroid insecticide commonly used in agricultural and urban sectors, is of concern. Concentrations measured in the Bay-Delta have been shown to disrupt the behavior, development, and endocrine system of other fish species. The objective of the present work was to assess the impact of bifenthrin on the early developmental stages of Longfin Smelt. For this, embryos were exposed to 2, 10, 100, and 500 ng/L bifenthrin from fertilization to hatch, and larvae were exposed to 2, 10, and 100 ng/L bifenthrin from one day before to 3 days post-hatch. We assessed effects on size at hatch, yolk sac volume, locomotory behavior, and upper thermal susceptibility (via cardiac endpoints). Exposure to these environmentally relevant concentrations of bifenthrin did not significantly affect the cardiac function of larval Longfin Smelt; however, exposures altered their behavior and resulted in smaller hatchlings with reduced yolk sac volumes. This study shows that bifenthrin affects the fitness-determinant traits of Longfin Smelt early life stages and could contribute to the observed population decline.

Biological Opinion and Conference Opinion on the Long-Term Operations of the Central Valley Project and State Water Project

National Marine Fisheries Service (NMFS) | June 4th, 2009

The purpose of this document is to present NOAA’s National Marine Fisheries Service’s (NMFS) biological and conference opinion (Opinion), about whether the U.S. Burea

The purpose of this document is to present NOAA’s National Marine Fisheries Service’s (NMFS) biological and conference opinion (Opinion), about whether the U.S. Bureau of Reclamation’s (Reclamation) proposed long-term operations of the Central Valley Project (CVP), operated in coordination with the State Water Project (SWP; hereafter referred to as CVP/SWP operations, the proposed action, or the project), is likely to jeopardize the continued existence of the following species  Endangered Sacramento River winter-run Chinook salmon (Oncorhynchus tshawytscha, hereafter referred to as winter-run)  Threatened Central Valley spring-run Chinook salmon (O. tshawytscha, hereafter referred to as spring-run)  Threatened Central Valley (CV) steelhead (O. mykiss)  Threatened Central California Coast (CCC) steelhead (O. mykiss)  Threatened Southern Distinct Population Segment (DPS) of North American green sturgeon (Acipenser medirostris, hereafter referred to as Southern DPS of green sturgeon)  Endangered Southern Resident killer whales (Orcinus orca, hereafter referred to as Southern Residents)  or destroy or adversely modify the designated critical habitat of the above salmon and steelhead species, or proposed critical habitat for Southern DPS of green sturgeon. This Opinion is based on the best scientific and commercial information available.