Optimizing the dammed: Water supply losses and fish habitat gains from dam removal in California

Journal of Environmental Management (Elsevier) | April 1st, 2014

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic an

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0–2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

Origins of Extreme Climate States during the 1982–83 ENSO Winter

American Meteorological Society (AMS) | November 1st, 1997

Other Resource Management Strategies

California Department of Water Resources (DWR) | July 29th, 2016

This narrative highlights a variety of water management strategies that can potentially generate benefits that meet one or more water management objectives, such as water

This narrative highlights a variety of water management strategies that can potentially generate benefits that meet one or more water management objectives, such as water supply augmentation or water quality enhancements. However, these management strategies have limited capacity to strategically address long-term regional water planning needs. These are unique strategies and do not fit into the other classified strategies. In some cases, such as dewvaporation, the strategy involves emerging technologies that will require more research and development. Other cases, such as crop idling and irrigated land retirement, involve voluntary and often temporary tradeoffs from one sector of use to another (i.e., agricultural to urban) that will likely be unpredictable and limited in scope. Finally, implementation of strategies, such as rainfed agriculture, will have limited applicability in California because of the variability and uncertainty of precipitation patterns from year to year. The strategies discussed in this resource management strategy report are: • Crop idling for water transfers. • Dewvaporation or atmospheric pressure desalination. • Fog collection. • Irrigated land retirement. • Rainfed agriculture. • Snow fences. • Waterbag transport/storage technology.

Our Built and Natural Environments: A Technical Review of the Interactions Among Land Use, Transportation, and Environmental Quality

U.S. Environmental Protection Agency (EPA) | June 13th, 2013

Decisions about how and where we build our communities have significant impacts on the natural environment and on human health. Cities, regions, sta

Decisions about how and where we build our communities have significant impacts on the natural environment and on human health. Cities, regions, states, and the private sector need information about the environmental effects of their land use and transportation decisions to mitigate growth‐ related environmental impacts and to improve community quality of life and human health.

Our Changing Planet: The U.S. Global Change Research Program for Fiscal Year 2025

U.S. Global Change Research Program (USGCRP) | January 3rd, 2025

This Fiscal Year 2025 edition of USGCRP’s annual report to Congress highlights advancements in science and information delivery that show how the Program is meeting nat

This Fiscal Year 2025 edition of USGCRP’s annual report to Congress highlights advancements in science and information delivery that show how the Program is meeting national needs. The Five-Year Progress section provides a longer-term look at USGCRP work on three selected topics: understanding the changing water cycle; responding to needs for climate information; and advancing diversity, equity, inclusion, justice, and accessibility across global change research efforts. We also highlight more recent activities in the 2023 Accomplishments section and look ahead to upcoming work in the Current and Future Priorities section.

Outdoor Recreation and Water Resources Planning

American Geophysical Union (AGU) | January 1st, 1974

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 3. To a considerable extent this work might be taken to be a report

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 3. To a considerable extent this work might be taken to be a report of progress in the analysis of recreational use of water and the implications for water resources planning. There has been considerable progress in recent years in the development of methods, some of which are hopefully reflected in these pages, and increasingly there are likely gains to their greater application. A major purpose here is to present some of the issues and methods in a somewhat systematic way so as to provide better appraisal of both problems and progress.

Overcoming Organizational Barriers to Implementing Local Government Adaptation Strategies

California Natural Resources Agency (CNRA) | August 27th, 2018

Local governments across California have taken immense strides to combat climate change. However, many local governments still face organizational barriers to comprehensi

Local governments across California have taken immense strides to combat climate change. However, many local governments still face organizational barriers to comprehensively implement climate change adaptation measures. Organizational barriers can delay and even prevent local governments from moving from adaptation planning to implementation due to the wide-reaching scope of climate change impacts. This study aims to further the understanding of the diversity of organizational barriers that California local governments experience and to develop a resource to assist local governments in their efforts to overcome these barriers to more effectively implement climate change adaptation strategies.  The research team conducted a broad literature review, an online survey, multiple regional stakeholder workshops, and focus groups to deepen the understanding of organizational barriers to adaptation in California local governments. These research inputs produced findings on organizational barriers experienced by California local government adaptation practitioners, and enabled the development and testing of the Adaptation Capability Advancement Toolkit. The Toolkit aims to help local governments rapidly assess their current capabilities to overcome organizational barriers and identify key actions and resources for increasing their organizational capability for undertaking climate change adaptation. The Toolkit is based on the Capability Maturity Model process improvement framework, and focuses on developing capabilities within four key process areas which were identified as common sources of organizational barriers: leadership and organizational culture, staffing and technical capacity, stakeholder engagement and partnerships, and operations and institutional processes. The Toolkit was tested by California local government adaptation practitioners in order to ground-truth recommendations and assess the utility of suggested actions and resources. Participants indicated that they view the resource as valuable, particularly if continuously supported. 

Overview of Disadvantaged Communities and Native American Tribes in the Santa Ana River Watershed

U.S. Bureau of Reclamation (USBR) | December 19th, 2003

This report provides a brief description of Disadvantaged Communities (DACs) and Native American Indian Tribes (Tribes) located in or near the Santa Ana River Watershed (

This report provides a brief description of Disadvantaged Communities (DACs) and Native American Indian Tribes (Tribes) located in or near the Santa Ana River Watershed (SARW), and a summary of water and related resource opportunities and challenges facing these entities.  The information was gathered from several sources including personal interviews, web research, documentation review, and publicly available information. This report addresses DACs and Tribes separately, as they each have very different and distinctive demographics and economic bases. This document is not meant to be an exhaustive analysis of their unique factors, but rather an introduction and, in some cases, an overview of these populations and their unique water resources requirements.  There are legitimate water quality issues that impact low income and Tribal communities throughout the SARW, but some perceptions of unsafe water where water supplies are clearly safe for public consumption identify another problem. The solution to these issues is to ensure that all communities have the information, financial and technical resources, and administrative and regulatory policies they need to make informed decisions that can result in benefits to all members of communities within the Watershed. One of the key provisions found through this research that could assist DACs is the 1996 Safe Drinking Water Act (SDWA) Amendments and the 2006 Safe Drinking Water State Revolving Fund (DWSRF) program.  Through the DWSRF, states can provide below-market interest rate loans to publicly and privately owned community water systems and nonprofit non-community water systems for necessary infrastructure improvements. States may also establish separate eligibility criteria and special funding options for economically disadvantaged communities through this program. Section 1452 of the SDWA defines a disadvantaged community as “the service area of a public water system that meets affordability criteria established after public review and comment by the State in which the public water system is located.” Under this section, states may provide additional subsidies (including forgiveness of principal) to communities that meet the established criteria, or that are expected to meet these criteria as a result of a proposed project. Though no special provision was found related to Tribes, the U.S. Environmental Protection Agency (EPA) supports “Tribal Assumption of Federal Environmental Laws” under federal statutes, stating, among other things, that “[t]he Agency will recognize tribal governments as the primary parties for setting standards, making environmental policy decisions, and managing programs for reservations, consistent with Agency standards and regulations.” Three Federal environmental statutes - the SDWA, the Clean Water Act, and the Clean Air Act - explicitly authorize EPA to “treat tribes in the same manner as states” for purposes of implementing various EPA environmental programs that may be of benefit to these communities.

Overview of the ARkStorm Scenario

U.S. Geological Survey (USGS) | January 13th, 2011

The U.S. Geological Survey, Multi Hazards Demonstration Project (MHDP) uses hazards science to improve resiliency of communities to natural disasters including ea

The U.S. Geological Survey, Multi Hazards Demonstration Project (MHDP) uses hazards science to improve resiliency of communities to natural disasters including earthquakes, tsunamis, wildfires, landslides, floods and coastal erosion. The project engages emergency planners, businesses, universities, government agencies, and others in preparing for major natural disasters. The project also helps to set research goals and provides decision-making information for loss reduction and improved resiliency. The first public product of the MHDP was the ShakeOut Earthquake Scenario published in May 2008. This detailed depiction of a hypothetical magnitude 7.8 earthquake on the San Andreas Fault in southern California served as the centerpiece of the largest earthquake drill in United States history, involving over 5,000 emergency responders and the participation of over 5.5 million citizens. This document summarizes the next major public project for MHDP, a winter storm scenario called ARkStorm (for Atmospheric River 1,000). Experts have designed a large, scientifically realistic meteorological event followed by an examination of the secondary hazards (for example, landslides and flooding), physical damages to the built environment, and social and economic consequences. The hypothetical storm depicted here would strike the U.S. West Coast and be similar to the intense California winter storms of 1861 and 1862 that left the central valley of California impassible. The storm is estimated to produce precipitation that in many places exceeds levels only experienced on average once every 500 to 1,000 years. Extensive flooding results. In many cases flooding overwhelms the state’s flood-protection system, which is typically designed to resist 100- to 200-year runoffs. The Central Valley experiences hypothetical flooding 300 miles long and 20 or more miles wide. Serious flooding also occurs in Orange County, Los Angeles County, San Diego, the San Francisco Bay area, and other coastal communities. Windspeeds in some places reach 125 miles per hour, hurricane- force winds. Across wider areas of the state, winds reach 60 miles per hour. Hundreds of landslides damage roads, highways, and homes. Property damage exceeds $300 billion, most from flooding. Demand surge (an increase in labor rates and other repair costs after major natural disasters) could increase property losses by 20 percent. Agricultural losses and other costs to repair lifelines, dewater (drain) flooded islands, and repair damage from landslides, brings the total direct property loss to nearly $400 billion, of which $20 to $30 billion would be recoverable through public and commercial insurance. Power, water, sewer, and other lifelines experience damage that takes weeks or months to restore. Flooding evacuation could involve 1.5 million residents in the inland region and delta counties. Business interruption costs reach $325 billion in addition to the $400 billion property repair costs, meaning that an ARkStorm could cost on the order of $725 billion, which is nearly 3 times the loss deemed to be realistic by the ShakeOut authors for a severe southern California earthquake, an event with roughly the same annual occurrence probability. The ARkStorm has several public policy implications: (1) An ARkStorm raises serious questions about the ability of existing federal, state, and local disaster planning to handle a disaster of this magnitude. (2) A core policy issue raised is whether to pay now to mitigate, or pay a lot more later for recovery. (3) Innovative financing solutions are likely to be needed to avoid fiscal crisis and adequately fund response and recovery costs from a similar, real, disaster. (4) Responders and government managers at all levels could be encouraged to conduct risk assessments, and devise the full spectrum of exercises, to exercise ability of their plans to address a similar event. (5) ARkStorm can be a reference point for application of Federal Emergency Management Agency (FEMA) and California Emergency Management Agency guidance connecting federal, state and local natural hazards mapping and mitigation planning under the National Flood Insurance Plan and Disaster Mitigation Act of 2000. (6) Common messages to educate the public about the risk of such an extreme disaster as the ARkStorm scenario could be developed and consistently communicated to facilitate policy formulation and transformation. These impacts were estimated by a team of 117 scientists, engineers, public-policy experts, insurance experts, and employees of the affected lifelines. In many aspects the ARkStorm produced new science, such as the model of coastal inundation. The products of the ARkStorm are intended for use by emergency planners, utility operators, policymakers, and others to inform preparedness plans and to enhance resiliency.

Overview on Central Valley Project Financing, Cost Allocation, and Repayment Issues

Delta Vision Blue Ribbon Task Force (Delta Vision) | September 18th, 2008

As part of its strategic plan, the Delta Vision Task Force is considering in detail the entire California water infrastructure. This report summarizes and expands upon

As part of its strategic plan, the Delta Vision Task Force is considering in detail the entire California water infrastructure. This report summarizes and expands upon four individual reports prepared for the Task Force on the financial characteristics and status of the Central Valley Project (CVP). It begins with an overview of CVP history, organization, costs, and repayment. It then focuses on the overall repayment responsibilities of irrigation and municipal and industrial (M&I) contractors as well as those responsibilities specifically for Sacramento Valley and San Joaquin Valley water users. Next is a review of the summary financial statements of the 10 largest San Joaquin Valley contractors based on reports filed with the California State Controller. Following is a discussion of CVP power generation revenues, expenditures, and repayment. The report is then summarized and conclusions presented, with subsequent appendices showing detailed financial statements and repayment responsibilities by individual contractors; and information on power sales over time to various users.