State Water Project Delivery Reliability Report (2002)

California Department of Water Resources (DWR) | May 1st, 2003

The Department of Water Resources is issuing this report to assist the contractors of the State Water Project in the assessment of the adequacy of the SWP component of th

The Department of Water Resources is issuing this report to assist the contractors of the State Water Project in the assessment of the adequacy of the SWP component of their overall water supplies. SWP delivery reliability is of direct interest to them and those they serve because it is an important element of their overall water supply. Local supply reliability is of key importance to local planners and government officials who have the responsibility to plan for future growth while assuring an adequate and affordable water supply is available for the existing population and businesses. This function is usually conducted in the course of preparing a water management plan such as the Urban Water Management Plans required by Water Code Section 10610. Information in this report may be used by local agencies in preparing or amending their water management plans and identifying the new facilities or programs that may be necessary to meet future water needs. Local agencies will also find this report useful in conducting analyses mandated by legislation authored by Senator Sheila Kuehl (SB 221) and Senator Jim Costa (SB 610). These laws require water retailers to demonstrate the sufficiency of their water supplies for certain proposed subdivisions and development projects subject to the California Environmental Quality Act.

State Water Project Delivery Reliability Report (2005)

California Department of Water Resources (DWR) | April 27th, 2006

The State Water Project Delivery Reliability Report 2005 presents DWR’s current information regarding the annual water delivery reliability of the State Water Project (

The State Water Project Delivery Reliability Report 2005 presents DWR’s current information regarding the annual water delivery reliability of the State Water Project (SWP) for existing and future levels of development in the water source areas, assuming historical patterns of precipitation. This report first looks at the general subject of water delivery reliability and then discusses how DWR determines delivery reliability for the SWP. A discussion of the analysis tool (the CalSim II computer simulation model), the analyses, and peer review regarding the accuracy of CalSim II and its suitability for use in this report is included. Finally, estimates of SWP delivery reliability today and in the future are provided along with examples of how to incorporate this information into local water management plans. This report responds to a requirement in the settlement agreement with the Planning and Conservation League to provide an assessment of the existing delivery capability of the SWP over a range of hydrologic conditions. The range of conditions is to include the historic extended dry cycle and the long-term average. In addition, the biennial report is to include the total amount of project water delivered and the amount of project water delivered to each contractor for each of the 10 years immediately preceding the report.

State Water Project Delivery Reliability Report (2009)

California Department of Water Resources (DWR) | August 31st, 2010

The State Water Project (SWP) is primarily a water storage and delivery system intended to help close the gap in California between when and where precipitation primarily

The State Water Project (SWP) is primarily a water storage and delivery system intended to help close the gap in California between when and where precipitation primarily falls and when and where most water demands occur. Water from the SWP is a critical component of water supply for the 29 state water contractors, who may also receive water from other sources. While each of the water supply contracts defines the maximum amount of water to be delivered annually, the amount of water actually delivered may be less due to such factors as variable precipitation and runoff, physical and institutional limits on storage and conveyance, and contractors’ variable water demands. For communities receiving SWP water, the reliability of SWP water deliveries is a key factor for local planners and government officials estimating their own water supply reliability. The 2009 State Water Project Delivery Reliability Report (2009 Report) updates the information contained in the 2007 Report by estimating the amounts of water deliveries for Current Conditions and conditions twenty years in the future. These estimates incorporate restrictions on SWP and Central Valley Project (CVP) operations in accordance with the biological opinions of the U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) issued on Dec. 15, 2008 and June 4, 2009, respectively. The estimates for Future Conditions also incorporate potential changes in hydrology due to climate change projections recommended by the Climate Action Team and sea level rise. This report briefly describes the SWP and the Sacramento-San Joaquin Delta (Delta), the hub of water deliveries in California. It discusses the general topic of water delivery reliability and how Department of Water Resources (DWR) calculates delivery reliability for the SWP. It then summarizes key planning activities that may affect future SWP delivery reliability. Three areas of significant uncertainty for SWP delivery reliability are discussed. They are climate change and sea level rise, the vulnerability of Delta levees to failure, and operation restrictions imposed by the USFWS and NMFS in response to decreasing populations of endangered fish species. Next, the general approach taken to simulate SWP operations using CALSIM II is discussed. This report presents the results of CALSIM II studies and compares them to previous estimates. Finally, this report provides guidance on how to apply the delivery estimates to water management plans. Presented in appendices are detailed CALSIM II simulation assumptions and results and recent SWP deliveries. This report does not include analyses of how specific water agencies should integrate SWP water supply into their water supply equation. This topic requires extensive information about local facilities, local water resources, and local water use, which is beyond the scope of this report. Moreover, such an analysis would require deci sions about water supply and use that tradition ally have been made locally. DWR believes that local officials should continue to fill this role.

State Water Project Delivery Reliability Report 2007

California Department of Water Resources (DWR) | August 1st, 2008

The water delivery reliability of the State Water Project (SWP) is at a crossroads. Future water deliveries to millions of Californians throughout the state will be impac

The water delivery reliability of the State Water Project (SWP) is at a crossroads. Future water deliveries to millions of Californians throughout the state will be impacted by many factors. Two of the most significant changes facing the system are Delta pumping restrictions and climate change. This report provides a glimpse of our current path if no action is taken to address these and other factors affecting water delivery reliability. The report also identifies many other factors that could be changed to positively affect our water future. Estimating the delivery reliability of the SWP depends on many issues, including possible future regulatory standards in the Delta, population growth, water conservation and recycling efforts, and water transfers. The impact of climate change on hydrology, consumptive use of water, fisheries and sea level rise must also be considered. This report evaluates the impacts of potential changes in hydrology of climate change. These other factors also need to be considered in the future. The stability of Delta levees, and therefore, SWP water deliveries, are threatened by earthquakes, land subsidence and floods. On the positive side, there are significant and promising processes underway that could take us to a much more reliable and sustainable Delta water conveyance system for the SWP. In this report, a possible future for these factors is presented. However, to the extent that these factors can be and are changed by actions over the next few years, this estimate of water delivery reliability will also change.

State Water Project Delivery Reliability Report 2011

California Department of Water Resources (DWR) | June 1st, 2012

The State Water Project Delivery Reliability Report 2011 (2011 Report) is the latest update to a biannual report that describes the existing and future conditions for Sta

The State Water Project Delivery Reliability Report 2011 (2011 Report) is the latest update to a biannual report that describes the existing and future conditions for State Water Project (SWP) water supply that are expected if no significant improvements are made to convey water past the Sacramento–San Joaquin Delta (Delta) or to store the more variable runoff that is expected with climate change. This report is presented in a different format than previous versions. The four previous reports were written for a dual audience—both the general public and those interested in a greater level of technical detail, such as the SWP contractors. By contrast, this report is written primarily with the public in mind. As a result, it not only provides updated information about the SWP’s water delivery reliability, but is also designed to educate Californians about the SWP and its operations. This report presents a concise description of the historical events leading to the construction of the SWP and describes the SWP’s facilities and operations. It then defines and explains the concept of water delivery reliability and the types of SWP water available to contractors, and describes various factors that affect the reliability of water deliveries. Because of the public interest in water project pumping from the Delta and the dependence of SWP water supply on Delta pumping, a new chapter has been added that focuses specifically on SWP pumping (exports) at the Harvey O. Banks Pumping Plant in the Delta. The 2011 Report shows that the SWP continues to be subject to reductions in deliveries similar to those contained in the State Water Project Delivery Reliability Report 2009 (2009 Report), caused by the operational restrictions of biological opinions (BOs) issued in December 2008 and June 2009 by the U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) to govern SWP and Central Valley Project operations. Federal court decisions have remanded the BOs to USFWS and NMFS for further review and analysis. We expect that the current BOs will be replaced sometime in the future. The operational rules defined in the 2008 and 2009 BOs, however, continue to be legally required and are the rules used for the analyses supporting the 2011 Report. The following “Summary” includes key findings of the analyses in the 2011 Report. A technical addendum is also available which provides detail on the assumptions of the analyses and the results for the 2011 Report. The results of the studies, as presented in this report and the technical addendum, are designed to assist water planners and managers in updating their water management and infrastructure development plans. These results emphasize the need for local agencies to develop a resilient and robust water supply, and a distribution and management system to maximize the efficient use of our variable supply. They also illustrate the urgent need to improve the method of conveying water past the Delta in a more sustainable manner that meets the dual goals of increasing water delivery reliability and improving conditions for endangered and threatened fish species.

State Water Project Delivery Reliability Report 2013

California Department of Water Resources (DWR) | December 1st, 2014

This State Water Project Delivery Reliability Report 2013 updates the estimated water delivery capability of the State Water Project (SWP) for current conditions and two

This State Water Project Delivery Reliability Report 2013 updates the estimated water delivery capability of the State Water Project (SWP) for current conditions and two decades from now. The estimates include the best-known future effects of climate change and the anticipated changes in Sacramento River basin land uses. Climate change will alter the timing and magnitude of inflows to upstream storage facilities including Shasta, Folsom, and Oroville reservoirs. In addition, rising sea levels will pose operational challenges to maintaining suitable salinity levels in San Francisco Bay and the Sacramento–San Joaquin Delta (Delta). Other factors in our analysis of SWP reliability have been assumed to not change over time. They are too uncertain to incorporate into the analysis. For example, regulatory restrictions issued by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service in their biological opinions are assumed to remain unchanged. The opinions dictate the timing and amounts of the SWP’s Delta exports. These restrictions are undergoing further review and analysis under a federal court order. Also, the Delta water quality and flow requirements contained in the State Water Resources Control Board’s water quality control plan for the Delta are assumed to remain unchanged. However, the board is revising its water quality control plan. Revisions to the plan and their subsequent inclusion into the California Department of Water Resources’ (DWR’s) water rights for the SWP could have a significant effect on SWP deliveries. The estimates in this report can be used by water districts as part of the analyses for their water management plans, which are required by State legislation to be updated in 2015. The report includes estimates for a range of hydrologic conditions that should be considered in water management plans. These estimates do not incorporate the risk of a disruption in SWP deliveries caused by catastrophic failure of Delta levees. Delta levee failure as a result of floods, earthquakes, erosion, or rising sea levels could interrupt water deliveries from the Delta for weeks, months, or even years, depending on the nature and the scope of the failure. Water management plans should describe the response to this potential scenario. This assessment of current and future SWP reliability is one of several efforts by DWR to help plan for reliable future water supplies in California.

State Water Project Historical Table A Allocations, Water Years 1996-2024

California Department of Water Resources (DWR)ia | June 5th, 2024

State Water Project Long-Term Drought Plan

California Department of Water Resources (DWR) | May 21st, 2024

The 2024 State Water Project (SWP) Long-Term Drought Plan consolidates information and actions taken during past droughts along with descriptions of the actions taken by

The 2024 State Water Project (SWP) Long-Term Drought Plan consolidates information and actions taken during past droughts along with descriptions of the actions taken by the SWP to plan for and prepare for future droughts.

State Water Project Seismic Loading Criteria Report

California Department of Water Resources (DWR) | September 19th, 2012

Seismic loading criteria are developed for various types of structures in the State Water Project (SWP) to use in future designs and evaluations. The SWP system supplies

Seismic loading criteria are developed for various types of structures in the State Water Project (SWP) to use in future designs and evaluations. The SWP system supplies water for almost two third of Californians and about 750,000 acres of irrigated farmlands. It is critical for the California economy. Seismic risk is considered one of the greatest contributors of all potential risk categories for the SWP. California is considered one of most seismically vulnerable areas in the world and most of the SWP facilities are located in central and southern California, which are seismically active areas. The purpose of developing seismic loading criteria was to have an economically feasible SWP system that would provide adequate protection against the loss of life, property damage, and interruption of water delivery during and immediately after a seismic event. Most of the existing SWP facilities have not been evaluated since they were built in the 1960s. The knowledge of ground motion predictions and seismic analytical methodologies has significantly progressed since the1960s. As part of the development of the seismic loading criteria, current design standards used by Department of Water Resources (DWR), other similar agencies, and regulatory/code entities were gathered and utilized to select appropriate minimum loading levels for different types of SWP facilities. In addition, the process of criteria selection included consideration of the consequences of failure such as loss of life, property damage, and interruption of water delivery. The consequence of interruption of water delivery was somewhat difficult to quantify because DWR delivers water to the water contractors and they either store it in their storage facilities or distribute to the local agencies. The recommended loading criteria include consideration of consequences of failures in the selection process. The Division of Engineering (DOE) in DWR should use the seismic loading criteria recommended in this report for the design and evaluation of both new and existing SWP facilities. Seismic loading criteria is provided for most of the structures associated with the SWP—reservoirs , dams, canals, pipelines, tunnels, check structures, pumping and power plants, buildings, bridges and utility overcrossings of the aqueduct. The seismic loading criteria should be used for these structures and associated appurtenant facilities in the future. A project engineer can use a larger loading criteria than what is recommended in this report based on project specific factors such as: 1) the consequences of interruption of water delivery, 2) the impact on existing habitats and the environment, 3) the operational aspects of the facility in relation to water delivery, 4) the repair cost and time to return the system back to operational status, and 5) the availability of an emergency back-up system to temporarily make the facility operational until all the repairs are completed. The criteria recommended in this report are considered current; however, these seismic loading criteria should be reviewed and updated every five years to make appropriate changes based on future operational requirements and on changes in state-of-practice. This is the first time DWR has developed loading criteria for the entire SWP facility and many of these facilities have not been evaluated to determine how vulnerable the system would be based on any seismic criteria. Therefore, these criteria are considered preliminary until the recommendations can be confirmed to be reasonable for the SWP facilities.

State Water Project Table A Allocations 1967-1995

California Department of Water Resources (DWR) | January 14th, 2022