California Aqueduct Subsidence Study

California Department of Water Resources (DWR) | June 1st, 2017

In 2006, the San Luis Field Division of the California Department of Water Resources' Division of Operations and Maintenance (O&M) began to see a reduction in flow ca

In 2006, the San Luis Field Division of the California Department of Water Resources' Division of Operations and Maintenance (O&M) began to see a reduction in flow capacity through the California Aqueduct (Aqueduct) Pools 20 and 21. Subsidence had lowered portions of the Aqueduct and caused the concrete liner freeboard (the vertical distance between the water surface and the top of the concrete liner) to be reduced from its normal of 3 feet, to less than 1 foot. Subsidence had also decreased the ability to store water in those pools, which is normally done to add operational flexibility and to manage pumping at the Aqueduct’s pumping plants. While subsidence has reduced the amount of freeboard and flow capacity at specific locations, contracted deliveries have not been curtailed through 2016. Additional work, to be addressed in the next phase of the project, will quantify how hydraulic limitations have impacted operations and will estimate future impacts to deliveries, based on forecasted subsidence rates. The purpose of this project is to research and study past and present subsidence reports and data, and to understand and summarize the magnitude, location, and effects on the Aqueduct. This report summarizes the significant information found, and presents the results of the data that were analyzed.

California Environmental Flows Framework

California State Water Resources Control Board (SWRCB) | March 31st, 2021

Multiple local, regional, and State agencies share responsibility for managing environmental flows, defined as the water required to protect the ecological health of Cali

Multiple local, regional, and State agencies share responsibility for managing environmental flows, defined as the water required to protect the ecological health of California streams while balancing human uses and other water management objectives. The process of developing environmental flow recommendations is complex, often involving multi-component technical studies and lengthy public discussions that can take years to complete. Although many environmental flow assessment tools exist, managers are often constrained to using either time-intensive, site-specific studies or a limited set of rapid desktop and regional approaches that have not been tailored to California. Furthermore, environmental flow assessments have not always been consistently designed and implemented in a way that allows data to be aggregated and shared, making it difficult to accelerate learning and improve the effectiveness of environmental flows in supporting the ecological health of California’s rivers and streams. Water managers need a consistent statewide approach that can help transform complex environmental data into scientifically defensible, easy-to-understand environmental flow recommendations that support a broad range of ecosystem functions1 and preserve the multitude of benefits provided by healthy rivers and streams. Having a consistent statewide approach would also improve statewide data compatibility and promote coordinated regional flow assessments that would benefit multiple agency programs working to improve the scale and pacing at which environmental flow protections can be extended to rivers and streams across the state.

California Fish and Game, Volume 34

California Fish and Game Commission | April 30th, 1948

California Salmon Strategy for a Hotter, Drier Future: Restoring Aquatic Ecosystems in the Age of Climate Change

California Department of Fish and Wildlife (CDFW) | January 20th, 2024

The infrastructure built generations ago in California continues to limit salmon migration, and some dams that remain on the landscape are well beyond their useful life.

The infrastructure built generations ago in California continues to limit salmon migration, and some dams that remain on the landscape are well beyond their useful life. In the Central Valley, large dams were built starting in the early 1900s on almost all major rivers. Those dams now block salmon access to over 90 percent of their historical spawning and rearing habitat higher in mountain streams.

California State Water Project 2006 Watershed Sanitary Survey Update

California Department of Water Resources (DWR) | June 20th, 2007

The State Water Project (SWP) provides drinking water to approximately two-thirds of California’s population and is the nation’s largest state-built water development

The State Water Project (SWP) provides drinking water to approximately two-thirds of California’s population and is the nation’s largest state-built water development project. The SWP extends from the mountains of Plumas County in the Feather River watershed to Lake Perris in Riverside County. It is linked with the Central Valley Project (CVP) that extends from southern Oregon in the Sacramento River watershed to the Mendota Pool. The watershed of the SWP is vast; encompassing the 27,000-square-mile Sacramento River and 13,000-square-mile San Joaquin River watersheds and at times, the 13,000-square-mile Tulare Basin watershed. The contaminant sources in the SWP watersheds have been well documented in the three previous sanitary surveys. The California Department of Health Services (CDHS) requested that the 2006 Update address the Jones Tract levee failure and emergency response procedures, efforts to coordinate pathogen monitoring in response to the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and a review of significant changes to the watersheds and their impacts on water quality.   A Technical Review Committee (TRC) was formed to guide development of the scope of work and provide technical expertise and review of the draft report. In addition to addressing the issues raised by CDHS, the TRC determined that the 2006 Update should focus on evaluating the sources of the water quality problems that the SWP Contractors face and recommending actions that the SWP Contractors can take that will lead to improvements in water quality over the next five years. TABLE OF CONTENTS CHAPTER 1 INTRODUCTION CHAPTER 2 REGULATORY SETTING CHAPTER 3 WATER QUALITY IN THE WATERSHEDS AND THE STATE WATER PROJECT CHAPTER 4 KEY CONCERNS IN THE CENTRAL VALLEY WATERSHED AND THE DELTA CHAPTER 5 KEY CONCERNS WITH STATE WATER PROJECT FACILITIES CHAPTER 6 INCIDENTS AND EMERGENCY RESPONSE MEASURES CHAPTER 7 CONCERNS WITH SYSTEM OPERATION AND MAINTENANCE

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.

CalSim 3 Results for 2070 Climate Change and Sea Level Projections and Sensitivity Analysis

California Department of Water Resources (DWR) | January 17th, 2024

This Technical Memorandum (TM) summarizes the key findings from a sensitivity analysis performed to analyze operations of the proposed Delta Conveyance Project (DCP) and

This Technical Memorandum (TM) summarizes the key findings from a sensitivity analysis performed to analyze operations of the proposed Delta Conveyance Project (DCP) and potential project water supply benefits under a range of potential scenarios for 2070 conditions. These scenarios consider climate change, sea level rise (SLR), and various water management responses. In addition, this sensitivity analysis also helps to identify whether proposed project operations and potential project impacts detailed in the Final DCP Environmental Impact Report (EIR) would remain similar or differ under a different climate change and SLR scenario under 2070 conditions, a more distant future.

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.

Central Valley Flood Protection Plan: Conservation Strategy

California Department of Water Resources (DWR) | August 8th, 2017

In the Central Valley of California, flood risks, water supplies, and the functioning of ecosystems are linked, with actions in one area affecting the other areas. The ma

In the Central Valley of California, flood risks, water supplies, and the functioning of ecosystems are linked, with actions in one area affecting the other areas. The majority of flows that pass through the State Plan of Flood Control (SPFC) are regulated by reservoirs operated for flood management, water supply, water quality, power generation, wildlife and fisheries habitat, and recreation. Similarly, the system of river and bypass channels, levees, and water control structures in the Central Valley does more than just contain floodwaters that previously flooded the valley floor for months at a time. It supports agricultural uses in the bypasses, serves as valued recreational areas and open space, helps in the management of surface water supplies and management of groundwater and water quality, and provides critical remnant riparian and floodplain habitats for numerous fish and wildlife species. The Central Valley Flood Protection Plan (CVFPP) recognizes these interconnections in its approach to flood management. The CVFPP is a long-term planning document that provides a framework for prioritization of investments in the SPFC. It seeks to improve flood risk management (the primary goal), as well as improve operations and maintenance (O&M), promote ecosystem functions, improve institutional support, and promote multi-benefit projects where feasible (supporting goals) (California Department of Water Resources [DWR] 2012a). This Conservation Strategy (or Strategy) is an integral part of the CVFPP. It supports the attainment of all CVFPP goals, but focuses on the improvement of ecosystem functions through the integration of ecological restoration with flood risk reduction projects where feasible. This Conservation Strategy, including Appendices A-L, describes the basis for recommending various conservation actions and setting long-term objectives for the Central Valley flood management system as a whole. The integration of specific environmental restoration features with DWR’s proposed flood management system improvements is summarized in Chapters 2 and 3 of the CVFPP and will also be described further in the 2017 CVFPP update and supporting documents, such as the Sacramento River Basin-Wide Feasibility Study (BWFS) and the San Joaquin River BWFS. The Conservation Strategy and CVFPP as a whole would contribute to achieving the California Water Action Plan’s overarching goals of  reliability, restoration, and resilience (California Natural Resources Agency, California Department of Food and Agriculture, and California Environmental Protection Agency 2015, 2016). In particular, this Strategy and the CVFPP as a whole are integral to three of the 10 “key actions” identified in the California Water Action Plan: Increase flood protection. Protect and restore important ecosystems. Increase operational and regulatory efficiency. Note: This document has extensive appendices and errata. Appendix A: Regulatory Setting, Appendix B: Advance Mitigation; Appendix C: Description of Construction Activities for Structural Modifications; Appendix D: Vegetation Management Strategy; Appendix E: Invasive Plant Management Plan; Appendix F: Existing Conditions; Appendix G: Identification of Target Species and Focussed Conservation Plans; Appendix H: Central Valley Chinook Salmon Rearing Habitat Needed to Satisfy the Anadromous Fish Restoration Program (AFRP) Doubling Goal; Appendix I: Floodplain Restoration Opportunities Analysis; Appendix J: Existing Conservation Objectives from other Plans; Appendix K: Synthesis of Fish Migration Improvement Opportunities in the Central Valley Flood System; Appendix L: Measurable Objectives Development - Summary of Conservation Needs and Scale of Restoration Opportunities; 2016 CVFPP Conservation Strategy: Errata; Conservation Strategy Development Process Overview

Central Valley Project (CVP) Water Contracts Fact Sheet

U.S. Bureau of Reclamation (USBR) | April 6th, 2016

Reclamation fact sheet on the Central Valley Project water contracts.

Reclamation fact sheet on the Central Valley Project water contracts.