The Delta on Fast Forward: Thinking Beyond the Next Crisis

CALFED | September 1st, 2016

The Delta Plan

Delta Stewardship Council (Delta Council) | May 16th, 2013

The Delta Plan is a comprehensive, long-term management plan for the Delta. Required by the 2009 Delta Reform Act, it creates new rules and recommendations to further the

The Delta Plan is a comprehensive, long-term management plan for the Delta. Required by the 2009 Delta Reform Act, it creates new rules and recommendations to further the state’s coequal goals for the Delta: Improve statewide water supply reliability, and protect and restore a vibrant and healthy Delta ecosystem, all in a manner that preserves, protects and enhances the unique agricultural, cultural, and recreational characteristics of the Delta. Now the Council is considering updates to the Delta Plan. For information about the amendment process, please click here. Developed through eights drafts, hundreds of hours of public meetings and thousands of public comments over two years, the Delta Plan is guided by the best available science and is founded on cooperation and coordination among federal, State and local agencies. The Delta Plan is enforceable through regulatory authority in the Delta Reform Act that requires state and local agencies to be consistent with the Delta Plan. The Delta Plan was unanimously adopted by the Delta Stewardship Council on May 16, 2013. Subsequently its 14 regulatory policies were approved by the Office of Administrative Law, a state agency that ensures the regulations are clear, necessary, legally valid, and available to the public. The Delta Plan became effective with legally-enforceable regulations on September 1, 2013.

The Economic Value of Carryover Storage in California’s Water Supply System with Limited Hydrologic Foresight

University of California, Davis (UC Davis) | July 1st, 2021

The security and prosperity of California’s economy depend on a large, interconnected and highly engineered water supply system with vast surface and groundwater stora

The security and prosperity of California’s economy depend on a large, interconnected and highly engineered water supply system with vast surface and groundwater storage operated for over-year storage. Substantial public investment is needed to maintain and improve these systems with changing climate risks, increasing demands, and aging infrastructure. Hydro-economic optimization identifies promising opportunities for managing such systems, but scientific and engineering advances are needed to better incorporate hydrologic uncertainty and conjunctive management of streams and aquifers into such models. Over two decades of research the California Value Integrated Network (CALVIN) linear programming hydro-economic model has yielded insights for California’s inter-regional water system on many fronts, including climate change, groundwater sustainability, conjunctive management in southern California, water markets, and reservoir operations in Northern California. Yet there remains unrealized potential to improve the model’s formulation to better represent inter-annual hydrologic variability while concurrently developing reservoir control rules. To address this gap, this study implements linearized quadratic carryover storage value functions on 26 surface reservoirs and linear groundwater storage penalties on 32 groundwater reservoirs to optimize California’s inter-regional water system seasonal and inter-annual operations with limited seasonal foresight. A convex Pareto front tradeoff between total system cost and groundwater overdraft is developed through multi-objective evolutionary optimization of inter-annual carryover storage penalties. Resulting over-year storage valuations span a wide range of nearoptimal reservoir operations, suggesting substantial system flexibility and adaptability when managed in an integrated way. Generalized relationships between carryover capacity, carryover use, and the marginal value of carryover storage are drawn for the multi-reservoir system. When compared to carryover operations based on California’s current simulation model, CalSim-II, the performance of these near-optimal reservoir operations suggests room to improve currently prescribed reservoir control rules, especially in supporting more  sustainable conjunctive management with aquifers. Overall, this study demonstrates the practicability, feasibility, and utility for understanding large-scale integrated multi-reservoir conjunctive use systems using limited foresight with explicit carryover storage values.

The Economic Value of Nature's Services and its role in Integrated Water Management: Four California Case Studies

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

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project foc

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project focuses on multiple water-related natural resources in a defined geographic area, usually a watershed. A common element of the projects is to show the economic benefits of protecting and restoring natural resources in a manner that allows their continued use over the long term. One of the aims of the projects is to recognize the economic value of the goods and services that nature provides and to incorporate that value into natural resource management decisions. Such recognition includes development of ways to measure the economic value of those services. This can be important information for water managers who normally see only the costs of ecosystem protection and restoration, but not the benefits, in their budgets. The goods and services considered in these projects include water supply, water quality, erosion prevention, wildfire prevention, hydropower generation, wood products, flood attenuation, carbon sequestration, land subsidence reversal, and fish and wildlife. Collectively, the projects constitute on-the-ground efforts to advance several of the objectives in the implementation plan of Water Plan 2009. In particular, they aim to expand integrated regional water management (objective 1), protect surface water and groundwater quality (objective 4), expand environmental stewardship (objective 5), practice integrated flood management (objective 6) and manage a sustainable California Delta (objective 7). The case studies accomplish and document several key ingredients of integrated resource management--although no single study does all of them. They identify and involve watershed stakeholders, both managers and users of natural resources. In turn, the stakeholders come to agreement about how they want the watershed to look or function, usually in terms of the goods and services that they want the watershed to provide. Then they reach agreement on a set of management practices that can support and enhance those services and move the watershed toward the desired condition. Finally, the case studies seek to estimate the amounts of goods and services derived from specific management practices. The pilot projects go beyond most watershed management efforts and most ecosystem services work in laying the foundation for establishment of markets for nature’s services, that is, mechanisms for beneficiaries to pay producers for goods and services they receive. This requires some sort of assessment of the monetary value of the benefits. One desired end product is to put payments in the hands of producers-- that is, resource managers—as an incentive to keep them producing.

The Economy of the State Water Project

California Department of Water Resources (DWR) | December 14th, 2023

The State Water Project (SWP) is among the world's most extensive water conveyance projects, featuring a 705-mile-long network of dams, reservoirs, hydroelectric faciliti

The State Water Project (SWP) is among the world's most extensive water conveyance projects, featuring a 705-mile-long network of dams, reservoirs, hydroelectric facilities, pumping plants, and canals. The State Water Project plays a key role in the state’s economy. It supplies over 27 million Californians, a majority of the state’s population, along with commercial and industrial customers, including in the technology and manufacturing sectors, that account for a majority of the state’s economic activity. Project deliveries also supply water to the agricultural sector, supporting the cultivation of fruits, vegetables, and nuts, particularly in the Central Valley, the nation’s most productive agricultural region. This reliable water source not only ensures the livelihood of residents, businesses, and farmers but also contributes significantly to the state’s economy through technology, manufacturing, and agricultural exports. This report consolidates publicly available data from the California Department of Water Resources (DWR) and other agencies to provide policymakers with a comprehensive overview of the economy that is supported by the State Water Project.

The effect of the El Niño-Southern Oscillation on U.S. regional and coastal sea level

American Geophysical Union (AGU) | June 3rd, 2015

Although much of the focus on future sea level rise concerns the long-term trend associated with anthropogenic warming, on shorter time scales, internal climate variabil

Although much of the focus on future sea level rise concerns the long-term trend associated with anthropogenic warming, on shorter time scales, internal climate variability can contribute significantly to regional sea level. Such sea level variability should be taken into consideration when planning efforts to mitigate the effects of future sea level change. In this study, we quantify the contribution to regional sealevel of the El Niño-Southern Oscillation (ENSO). Through cyclostationary empirical orthogonal function analysis (CSEOF) of the long reconstructed sea level data set and of a set of U.S. tide gauges, two global modes dominated by Pacific Ocean variability are identified and related to ENSO and, by extension, the Pacific Decadal Oscillation. By estimating the combined contribution of these two modes to regional sealevel, we find that ENSO can contribute significantly on short time scales, with contributions of up to 20 cm along the west coast of the U.S. The CSEOF decomposition of the long tide gauge records around the U.S. highlights the influence of ENSO on the U.S. east coast. Tandem analyses of both the reconstructed and tidegauge records also examine the utility of the sea level reconstructions for near-coast studies.

The Enduring Role of Tribes in the Colorado River Basin

Water and Tribes Initiative | July 1st, 2019

The purpose of this policy brief is to explain the origin, rationale, and purpose of the Water & Tribes Initiative in the Colorado River Basin. As explained more fully be

The purpose of this policy brief is to explain the origin, rationale, and purpose of the Water & Tribes Initiative in the Colorado River Basin. As explained more fully below, the long-term objectives of this Initiative are to: • Enhance the capacity of tribes to advance their needs and interests with respect to water management in the basin; and • Advance sustainable water management through collaborative decision-making.

The Essential Role of Local Context in Shaping Risk and Risk Reduction Strategies for Snowmelt-Dependent Irrigated Agriculture

American Geophysical Union (AGU) | June 11th, 2024

The Evaporative Demand Drought Index. Part I: Linking Drought Evolution to Variations in Evaporative Demand

American Meteorological Society (AMS) | March 1st, 2016

Many operational drought indices focus primarily on precipitation and temperature when depicting hydroclimatic anomalies, and this perspective can be augmented by analys

Many operational drought indices focus primarily on precipitation and temperature when depicting hydroclimatic anomalies, and this perspective can be augmented by analyses and products that reflect the evaporative dynamics of drought. The linkage between atmospheric evaporative demand E0 and actual evapotranspiration (ET) is leveraged in a new drought index based solely on E0—the Evaporative Demand Drought Index (EDDI). EDDI measures the signal of drought through the response of E0 to surface drying anomalies that result from two distinct land surface–atmosphere interactions: 1) a complementary relationship between E0 and ET that develops under moisture limitations at the land surface, leading to ET declining and increasing E0, as in sustained droughts, and 2) parallel ET and E0 increases arising from increased energy availability that lead to surface moisture limitations, as in flash droughts. To calculate EDDI from E0, a longterm, daily reanalysis of reference ET estimated from the American Society of Civil Engineers (ASCE) standardized reference ET equation using radiation and meteorological variables from the North American Land Data Assimilation System phase 2 (NLDAS-2) is used. EDDI is obtained by deriving empirical probabilities of aggregated E0 depths relative to their climatologic means across a user-specific time period and normalizing these probabilities. Positive EDDI values then indicate drier-than-normal conditions and the potential for drought. EDDI is a physically based, multiscalar drought index that that can serve as an indicator of both flash and sustained droughts, in some hydroclimates offering early warning relative to current operational drought indices. The performance of EDDI is assessed against other commonly used drought metrics across CONUS in Part II.

The frontiers of water and sanitation

Nature Portfolio (Springer Nature) | January 19th, 2023

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable tech

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable technologies and infrastructure. Furthermore, a stronger and wider appreciation of water inequalities and injustice demand an adequate transformation of water governance at local and global scale. We have asked nine experts in various sectors of water-related research to share their views on how water and sanitation science, technology and governance must evolve to meet the requirements of a healthier relationship between water and society.