May Revision Trailer Bill Proposals on the Delta Conveyance Project and Water Quality Control Plans

Legislative Analyst's Office (LAO) | May 27th, 2025

LAO Bottom Line: We recommend deferring action on both proposals, without prejudice. These policy issues do not have budget implications. Deferring action would allow the

LAO Bottom Line: We recommend deferring action on both proposals, without prejudice. These policy issues do not have budget implications. Deferring action would allow the Legislature more time and capacity for sufficient consideration of the potential benefits, implications, and trade-offs. Below, we describe the proposals and note some key issues for the Legislature to keep in mind when it considers these proposals.

McMullin Area Groundwater Sustainability Agency Groundwater Sustainability Plan

McMullin Area Groundwater Sustainability Agency (MAGSA) | November 6th, 2019

McMullin Area Groundwater Sustainability Agency Groundwater Sustainability Plan (Revised)

McMullin Area Groundwater Sustainability Agency (MAGSA) | July 6th, 2022

Mean and Extreme Climate Change Impacts on the State Water Project

California Department of Water Resources (DWR) | August 27th, 2018

Warming temperatures, shifting hydrology, and rising sea levels will challenge management of California’s water resources. This study quantifies climate change risks t

Warming temperatures, shifting hydrology, and rising sea levels will challenge management of California’s water resources. This study quantifies climate change risks to California’s State Water Project (SWP) and federal Central Valley Project (CVP). This study uses the California Department of Water Resources’ (DWR’s) newly developed water planning model, CalSim 3.0, as a risk assessment tool. Impacts were assessed for 20 climate change scenarios (10 global climate models and two emission scenarios, representative concentration pathway (RCP) 4.5 and RCP 8.5). Water supply and water quality metrics evaluated include Delta exports, North of Delta Carryover storage, reservoir dead storage (i.e. when reservoir levels fall below the lowest outlets), and Delta salinity. Results for the driest future scenario were also analyzed to examine future drought impacts. In addition, a series of sensitivity tests were implemented to assess individual impacts of four climate change factors: flow seasonal pattern shift, sea level rise, annual flow volume change, and water demand change on the State Water Project and Central Valley Project operations. It was found that flow seasonal pattern shift will become a major climate change factor and sea level rise a secondary factor, leading to a half million‐acre feet of Delta export reduction as well as a roughly 25% decrease of North‐of‐Delta carryover storage by around 2060. The results also indicate that the extra runoff from early snow melting and higher percentage of rain in the winter and early spring is not conserved in reservoirs and thus cannot be used to meet the higher summer demand in the current SWP/CVP system. This extra water is released as flood water in the winter and early spring to become Delta outflow.

Measuring and Interpreting Multilayer Aquifer-System Compactions for a Sustainable Groundwater-System Development

American Geophysical Union (AGU) | March 23rd, 2021

Ever decreasing water resources and climate change have driven the increasing use of groundwater causing land subsidence in many countries. Geodetic sensors such as InSAR

Ever decreasing water resources and climate change have driven the increasing use of groundwater causing land subsidence in many countries. Geodetic sensors such as InSAR, GPS and leveling can detect surface deformation but cannot measure subsurface deformation. A single‐well, single‐depth extensometer can be used to measure subsurface deformation, but it cannot delineate the depths of major compaction and provide insight about the deformation mechanism throughout a complex aquifer system, unless man extensometers at different depths are used. We present a multilayer compaction well (MLCW), installed in a borehole, that uses magnetic rings to detect stratum compaction at 25 depths as deep as 300 m below land surface. Our laboratory and field assessments indicate 1 mm precision and accuracy for one single‐depth magnetic reading. We tested the performance of MLCW by measuring aquifer‐system compaction over the proximal, middle, and distal fans of the Choushui River Alluvial Fan (CRAF) that has long experienced severe land subsidence. The MLCW measurements were used to create time‐depth diagrams of compaction, showing different compaction rates at different layers of aquifers and aquitards to identify the depths of major compactions. The elastic (reversible) and inelastic (irreversible) compactions from MLCW were used in stress‐strain analyses to estimate skeletal specific storages and the safe groundwater levels, below which groundwater extractions have caused irreversible compactions. The hydrogeological parameters derived from MLCW measurements can help governmental agencies to determine effective land‐use and water‐use policies, and ascertain the best strategy for utilizing artificial recharge to prevent land subsidence and achieve sustainable groundwater management.

Measuring Cost-Effectiveness of Environmental Water Transactions

Klamath Riverkeeper | August 4th, 2016

The diversion, storage and consumptive use of water in the western United States (US) has drastically altered streamflow, water quality and a raft of ecological, social a

The diversion, storage and consumptive use of water in the western United States (US) has drastically altered streamflow, water quality and a raft of ecological, social and economic goods and services. Over the last fifty years, western states have begun to address this problem through a range of approaches. Water quality regulations, endangered species protections, application of the public trust doctrine to water allocations and other regulatory approaches reflect an effort to prevent further degradation of streamflow and associated values. For example, in Oregon, minimum streamflow requirements created in the 1950s were converted into full-fledged instream water rights in the 1980s and 1990s to limit further appropriations of water for out-of-stream use. Unfortunately, as junior (or low) priority rights, these rights do not serve to restore flow to already dewatered streams. In other cases, both large and small, regulatory enforcement has led to real improvements in water for the environment. In California, the protections afforded to Mono Lake water levels and the re-dedication of contract water to environmental uses under the Central Valley Project Improvement Act, are but two examples. However, the controversy, costs and lengthy time span of dedicating water to the environment through litigation and regulatory approaches are unappealing to some conservation groups, particularly those that prefer to collaborate and purchase water rather than litigate to achieve streamflow restoration. An alternative approach to meet streamflow restoration needs is to proactively negotiate in the “water market” for the acquisition of existing out-of-stream rights or for changes in water use and management in order to benefit the environment. These transactions result in “environmental flows,” including the dedication or protection of water instream or the provision of water to Roughly 80% of California’s developed water supply is used for agricultural irrigation.*

Measuring Land Subsidence from Space

U.S. Geological Survey (USGS) | April 13th, 2000

Interferometric Synthetic Aperture Radar (InSAR) is a powerful new tool that uses radar signals to measure deformation of the Earth’s crust at an unprecedented level of

Interferometric Synthetic Aperture Radar (InSAR) is a powerful new tool that uses radar signals to measure deformation of the Earth’s crust at an unprecedented level of spatial detail and high degree of measurement resolution. InSAR is now being used by the USGS and others to map and monitor subsidence caused by the compaction of aquifer systems. Geophysical applications of radar interferometry take advantage of the phase component of reflected radar signals to measure apparent changes in the range distance of the land surface (Gabriel and others, 1989; Massonnet and Feigl, 1998). Ordinary radar on a typical Earth-orbiting satellite has a very poor ground resolution of about 3 to 4 miles because of the restricted size of the antenna on the satellite. Synthetic Aperture Radar (SAR) takes advantage of the motion of the spacecraft along its orbital track to mathematically reconstruct (synthesize) an operationally larger antenna and yield high-spatial-resolution imaging capability on the order of hundreds of feet.

Measuring Progress Toward Universal Access to Water and Sanitation in California Defining Goals, Indicators, and Performance Measures

Pacific Institute | September 13th, 2018

Most people in California take for granted the water and sanitation in their homes. They turn the tap and clean, relatively inexpensive, abundant water flows out.

Most people in California take for granted the water and sanitation in their homes. They turn the tap and clean, relatively inexpensive, abundant water flows out. They flush the toilet, and waste vanishes. Yet there are communities in California who do not have these basic necessities in their homes. In January 2018, over half a million Californians were served by water utilities that were out of compliance with the Safe Drinking Water Act (SDWA). The worst outbreak of Hepatitis A in recent memory occurred in 2016-2018 due to open defecation and lack of handwashing facilities for persons experiencing homelessness. California’s tribes continue to face problems of poor housing and water and sanitation service, with two-thirds of tribal communities reporting inadequate home plumbing in 2015. And the cost of water has increased for many, particularly among small and medium size systems, with 39 community water systems in the state charging more than $100 a month for 12 CCF of water. In response to the problem, California enacted the Human Right to Water in 2012, declaring that “Every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” The California State Water Resources Control Board (State Water Board) further recognized the need to address water and sanitation for disadvantaged communities when it adopted a resolution directing staff to “develop performance measures for the evaluation of the board’s progress towards the realization of the human right to water, evaluate that progress, and explore ways to make that information more readily available to the public,” and to “work with... stakeholders to develop new or enhance existing systems to collect the data needed to identify and track communities that do not have, or are at risk of not having, safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” This report offers a unified framework on how to measure progress toward universal access to water and sanitation in California.

Measuring Progress Toward Universal Access to Water and Sanitation in California: Defining Goals, Indicators, and Performance Measures

Pacific Institute | September 15th, 2018

In January 2018, over half a million Californians were served by water utilities that were out of compliance with the Safe Drinking Water Act (SDWA). The worst outbreak o

In January 2018, over half a million Californians were served by water utilities that were out of compliance with the Safe Drinking Water Act (SDWA). The worst outbreak of Hepatitis A in recent memory occurred in 2016-2018 due to open defecation and lack of handwashing facilities for persons experiencing homelessness. California’s tribes continue to face problems of poor housing and water and sanitation service, with two-thirds of tribal communities reporting inadequate home plumbing in 2015.1 And the cost of water has increased for many, particularly among small and medium size systems, with 39 community water systems in the state charging more than $100 a month for 12 CCF of water. In response to the problem, California enacted the Human Right to Water in 2012, declaring that “Every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.”

Measuring What Matters: Setting Measurable Objectives to Achieve Sustainable Groundwater Management in California

Union of Concerned Scientists | September 1st, 2015

Groundwater supplies between 30 and 50 percent of California’s water supply, depending on precipitation, and represents a storage reservoir that is over three times gre

Groundwater supplies between 30 and 50 percent of California’s water supply, depending on precipitation, and represents a storage reservoir that is over three times greater than available surface water storage. The California Water Action Plan (CNRA, CDFA, and CEPA 2014) identifies groundwater as “a critical bu?er to the impacts of prolonged dry periods and climate change on our water system.” Many groundwater basins have historically experienced significant chronic overdraft and related negative impacts. California’s ongoing drought helped spur the state to enact legislation to strengthen local control and management of groundwater basins. Governor Jerry Brown signed the threebill package (AB 1739, SB 1168, SB 1319), known as the Sustainable Groundwater Management Act (SGMA), into law on September 16, 2014. SGMA represents California’s attempt to regulate groundwater comprehensively for the first time in the state’s history. SGMA, which went into e?ect on January 1, 2015, lays out a process and a timeline for local agencies to achieve sustainable management of groundwater basins (see Box 1). It also provides tools, authorities, and deadlines meant to lead to achievement of the legislation’s purpose. For local agencies involved in implementation, the requirements are significant and are expected to take many years to accomplish. While setting measurable objectives is a new requirement, it is by no means a new concept in natural resource management. This report summarizes the theory and practice of setting measurable objectives for groundwater management, using examples from California and elsewhere. The goal is to begin to develop a shared knowledge base and to identify key features of e?ective measurable objectives.