California Water Plan 2013: Sacramento-San Joaquin Delta Regional Report

California Department of Water Resources (DWR) | October 30th, 2014

Some areas of the state with common water issues or interests cross the boundaries from one hydrologic region to another. To acknowledge this, the California Department o

Some areas of the state with common water issues or interests cross the boundaries from one hydrologic region to another. To acknowledge this, the California Department of Water Resources (DWR) developed the concept of “overlay areas” and first described overlay areas in California Water Plan Update 2005. The purpose of the overlay areas is to collect and provide information that will better enable planners and decision-makers to address issues in areas of special interest where both of the following criteria apply: (1) the area is of statewide significance — meaning that water management strategies and actions taken in one area affect much of the remainder of the state — and (2) common water management conditions exist in the area — meaning that issues and integrated planning opportunities span more than one of the 10 hydrologic regions. The two overlay areas of special interest are the Sacramento-San Joaquin Delta (Delta) and Mountain Counties.  For Update 2005, the Delta and Suisun Marsh were included as an overlay area because of its common characteristics, environmental significance, and the important role it has in the State’s water systems. The Delta and Suisun Marsh encompasses about 840,000 acres of tidal influenced land near the confluence of the Sacramento and San Joaquin rivers; and occupies portions of the Sacramento, San Joaquin, and San Francisco hydrologic regions. The geographic extent of the Delta overlay coincides with the statutory Delta boundary that defines the Legal Delta (California Water Code [CWC] Section 12220) and the Suisun Marsh as defined in California Public Resources Code Section 29101.

California water seen as environment issue, not North vs. South

Christian Science Monitor | June 13th, 1984

Sooner or later southern Californians are going to get more water from the north. And yet the newest proposal to do it has rekindled the political rift over water policy

Sooner or later southern Californians are going to get more water from the north. And yet the newest proposal to do it has rekindled the political rift over water policy that makes compromise difficult. The new plan would expand channels feeding the main north-south aqueduct, and it raises issues tinged with sentiment that is typically Californian. Traditionally labeled a north-south rivalry, the water issue today is more correctly an illustration of a statewide credo often that gives equal weight to the often conflicting goals of environ-mentalism and economic prosperity. Gov. George Deukmejian's water plan - called the ''through-delta canal'' - would increase water flowing through the Sacramento-San

California Wetland and Riparian Area Protection Policy Technical Memorandum No. 5: Stream Definition

San Francisco Estuary Institute (SFEI) | April 20th, 2016

With this memorandum, the Technical Advisory Team (TAT) recommends a definition of California streams to the Policy Development Team (PDT) of the State Water Quality Cont

With this memorandum, the Technical Advisory Team (TAT) recommends a definition of California streams to the Policy Development Team (PDT) of the State Water Quality Control Board (State Water Board) for its Wetland and Riparian Area Protection Policy (WRAPP). This memorandum does not recommend any process or procedure for identifying, delineating, or classifying streams, nor are such recommendations being planned by the TAT at this time. However, the TAT recommends that such processes and procedures should be developed in the future to support the WRAPP. The California Wetland Monitoring Workgroup (CWMW) is preparing recommendations for stream mapping as part of the recommending methodology of the California Aquatic Resource Inventory (CARI). 

California’s Agricultural and Urban Water Supply Reliability and the Sacramento–San Joaquin Delta

University of California, Davis (UC Davis) | October 13th, 2016

Much of the water supplied in California for agriculture and cities is taken directly from the Sacramento–San Joaquin Delta (Delta) or indirectly from surface and groun

Much of the water supplied in California for agriculture and cities is taken directly from the Sacramento–San Joaquin Delta (Delta) or indirectly from surface and groundwater diversions upstream. These water supplies have great economic and social value, and considerable ecosystem effects. Long thought of as the major source of water for economic growth in California, the reliability of water supplied from the Delta is threatened by drought, flood, climate change, earthquakes, growing water demands, and deteriorating conditions for endangered species and native ecosystems. Research in recent years has improved understanding of how management of the Delta ties together the quantity and quality of water available statewide. These ties run from the Sierra mountains and coastal streams, through the Central Valley, to the San Francisco Bay Area, and over the Tehachapi Mountains to southern California. For decades, Californians counted on reducing Delta outflows to supply water for growing water demands in its watershed and in water importing areas. With greater competition for water, concern for environmental effects, and a changing climate, the reliability of such supplies is now diminishing. This must lead to tighter accounting and modeling of water supplies in the Delta and throughout its watershed. This paper reviews issues about Delta water supplies, operations, regulations, and reliability; the economic value of supply; costs of unreliability in quantity and quality; and several directions for further scientific and technical work on water supply reliability.

California’s Future: Water

Public Policy Institute of California (PPIC) | January 31st, 2020

Water management in California has always been challenging. The state’s variable climate is marked by long droughts and severe floods, with stark regional dif

Water management in California has always been challenging. The state’s variable climate is marked by long droughts and severe floods, with stark regional differences in water availability and demand. California’s “water grid”—the network of surface and groundwater storage and conveyance systems that connects most water use in the state—was designed to move water to population and farming centers in the Bay Area, the San Joaquin Valley, and Southern California, while also protecting residents from floods. As the state has changed, its water challenges have intensified. The Sacramento–San Joaquin Delta is an increasingly fragile link in the water grid. California’s extensive network of dams is aging. Agricultural demand is becoming less flexible, as farmers increase tree crops (especially nuts), which must be watered every year. Some poor—mostly rural— communities lack safe drinking water. Conflicts are growing between human water use and water needed for fish and other wildlife. And the latest cycle of droughts and floods highlights the growing threat of climate change. Climate pressures are making it harder to simultaneously store water for droughts, manage flood risk, and protect fresh- water ecosystems. But leaders across the state are addressing the challenges of a more volatile climate, and the Newsom administration is developing a water resilience portfolio to adapt all aspects of water management to the “new normal.”

CalSim II Simulation of Historical SWP-CVP Operations Technical Memorandum Report

California Department of Water Resources (DWR) | November 12th, 2003

CalSim is a generalized water resources planning tool developed jointly by the Department of Water Resources (DWR) and the US Bureau of Reclamation Mid-Pacific Region (Re

CalSim is a generalized water resources planning tool developed jointly by the Department of Water Resources (DWR) and the US Bureau of Reclamation Mid-Pacific Region (Reclamation). CalSim II is the application of the CalSim software to model the State Water Project (SWP), the federal Central Valley Project (CVP) and areas tributary to the Sacramento-San Joaquin Delta (Delta). The primary purpose of the CalSim II model is to evaluate the water supply reliability of the CVP and SWP, 1) at current or future levels of development, 2) with and without various assumed future facilities and, 3) with different modes of facilities operations. The purpose of the Historical Operations Study is to evaluate the ability of CalSim-II to represent CVP and SWP operations, in general, and the delivery capability of the projects, in particular, through the monthly simulation of recent historical conditions. The Historical Operations Study is part of a larger CalSim II evaluation process. Other components of the evaluation include a survey of the water community to gather their views and opinions of the model, a model peer review by leading academics and practitioners, and a sensitivity analysis on model inputs. It is hoped that this effort, to assess the quality and limitations of CalSim II, will lead to a wider debate about critical model issues, help direct model development in both the near and long term, and eventually lead to greater public confidence and acceptance of the model.

Carbon Sequestration and Subsidence Reversal in the Sacramento–San Joaquin Delta and Suisun Bay: Management Opportunities for Climate Mitigation and Adaptation

University of California, Davis (UC Davis) | August 28th, 2023

Carriage Water

California Department of Water Resources (DWR) | September 26th, 2001

Carriage water is defined as marginal export costs, that is, the extra water needed to carry a unit of water across the Delta to the pumping plants while maintaining a co

Carriage water is defined as marginal export costs, that is, the extra water needed to carry a unit of water across the Delta to the pumping plants while maintaining a constant salinity. Or more practically, when the exports are increased by one unit, the Sacramento flow is increased by one unit plus carriage water to maintain a constant Delta salinity. It has been known for several years that the current method of estimating carriage water in DWRSIM, called the Minimum Delta Outflow (MDO) Routine, is not particularly accurate in individual years and a better method needed. The Delta is a complex system and past attempts at developing a useful method for measuring carriage water and ultimately an MDO replacement always had at least one major flaw. An attempt was made to search for carriage water directly in the historical data, that is, to find a period of time when Net Delta Outflow (NDO) is fairly constant, but Sacramento flow and exports are increasing. If carriage water existed, salinity at interior Delta stations should increase. While there are a few times when this seems to be true (e.g. summer 1979 and 1994), the salinity increase could also be explained by antecedent conditions, that is, previous to the period of constant NDO, NDO was much higher, and the salinity increase could be simply due to the Delta gradually reaching new equilibrium. Thus it became apparent that only a model of the Delta could say anything about carriage water.

Case History No. 9.14. Santa Clara Valley, California, U.S.A.

United Nations Educational, Scientific and Cultural Organization (UNESCO) | June 30th, 1984

Central Valley Flood Protection Plan (2012)

California Department of Water Resources (DWR) | June 12th, 2012

The Central Valley Flood Protection Plan (CVFPP) is a critical document to guide California’s participation (and influence federal and local participation) in managing

The Central Valley Flood Protection Plan (CVFPP) is a critical document to guide California’s participation (and influence federal and local participation) in managing flood risk along the Sacramento River and San Joaquin River systems. The CVFPP proposes a system-wide investment approach for sustainable, integrated flood management in areas currently protected by facilities of the State Plan of Flood Control (SPFC). The CVFPP will be updated every five years, with each update providing support for subsequent policy, program, and project implementation. The State of California (State) conducted planning and investigations for the 2012 CVFPP from 2009 through 2011, representing the most comprehensive flood evaluations for the Central Valley. Following the anticipated adoption of the CVFPP in 2012 by the Central Valley Flood Protection Board (Board), preparation of regional- and State-level financing plans will guide investments in the range of $14 billion to $17 billion during the next 20 to 25 years.  These financing plans are critical to CVFPP implementation, given the uncertainty in State, federal, and local agency budgets and cost-sharing capabilities.