Water and the Future of the San Joaquin Valley

Public Policy Institute of California (PPIC) | February 14th, 2019

The San Joaquin Valley—California’s largest agricultural region and an important contributor to the nation’s food supply—is in a time of great change. The valle

The San Joaquin Valley—California’s largest agricultural region and an important contributor to the nation’s food supply—is in a time of great change. The valley is ground zero for many of California’s most difficult water management problems—including groundwater overdraft, drinking water contamination, and declines in habitat and native species. Local water supplies are limited, particularly in the southern half of the region. To irrigate their crops, many farmers use water imported from the Sacramento–San Joaquin Delta. But in many places farmers have also relied on groundwater overdraft—pumping groundwater in excess of the rate at which it is replenished. Worsening droughts, increasing regulations to protect endangered native fishes, and growing demand by Southern California for Delta imports have compounded surface water scarcity. The state’s Sustainable Groundwater Management Act (SGMA) requires local water users to bring groundwater use to sustainable levels by the early 2040s. This will have a broad impact on valley agriculture and the regional economy in coming years—likely including some permanent idling of farmland. This report explores three key challenges facing the San Joaquin Valley and reviews the most promising approaches to address them:  Balancing water supplies and demands. To close the groundwater deficit, groundwater sustainability agencies in the valley’s overdrafted basins will have to augment supplies, reduce demands, or use some combination of these two approaches. A range of options are under consideration but they are not equally effective or practical.  Addressing groundwater quality challenges. Poor groundwater quality impairs drinking water supplies in disadvantaged rural communities, reduces long-term agricultural prosperity, and degrades ecosystems. Providing safe drinking water is an urgent priority. Over the longer term, parties will also need to manage water quantity and quality together, to take advantage of synergies and avoid unintended consequences. The necessary coordination will be challenging because the various programs addressing valley water quality issues are carried out by numerous local and regional entities, whose lines of responsibility and geographic boundaries do not neatly align.  Fostering beneficial water and land use transitions. Effectively addressing water scarcity and the resulting land use changes in the San Joaquin Valley offers opportunities to put lands coming out of production to good use—and gain “more pop per drop” from limited water resources. Multiple-benefit approaches to water and land management can enhance groundwater recharge and improve air and water quality. They can also promote healthier soils, new recreational opportunities, additional flood protection, improved habitat, and new revenue streams for private landowners engaging in conservation-oriented management. Addressing these complex and intertwined issues requires significant changes in water and land management and a major ramp-up in cooperation and coordination among a wide circle of stakeholders. Pursuing solutions that deliver multiple benefits will boost the chances of success overall. The entire region—and California as a whole—will benefit if solutions to these challenges are cost-effective and support the valley’s economy while improving public health and the natural environment.

Water Available for Replenishment 2018

California Department of Water Resources (DWR) | April 12th, 2018

Water Blueprint for the San Joaquin Valley Economic Impact Analysis: Phase One Results

Water Blueprint for San Joaquin Valley | February 15th, 2020

Water Budget Development for SGMA Compliance, Case Study: Ukiah Valley Groundwater Basin

Universities Council on Water Resources Journal of Contemporary Water Research & Education | December 28th, 2017

The Sustainable Groundwater Management Act (SGMA) is the first comprehensive legislative effort to reform groundwater management in the state of California after years of

The Sustainable Groundwater Management Act (SGMA) is the first comprehensive legislative effort to reform groundwater management in the state of California after years of uncoordinated and voluntary governance of this resource. The objective of this study is to: a) describe the SGMA in California, b) describe a method for estimating a water budget, and c) present the implementation of this method for the Ukiah Valley Groundwater Basin (UVGB). An estimated water budget, done on a monthly time step from 1991 to 2015, was developed in order to characterize the UVGB. Results suggest that the groundwater basin is not in overdraft, and that a portion of the Russian River is a gaining river (approximately 18,952 AF/y) from November to June, and a losing river (approximately 393 AF/y) from July to October. Furthermore, lateral groundwater movement is identified through the groundwater mass balance. Based on previous work and the results of this study, the observed later groundwater losses signify connectivity between the UVGB and the Sanel Valley Groundwater Basin (SVGB). Local groundwater managers and users can use this information to inform proposed action plans and monitoring protocols that will allow them to achieve and maintain groundwater sustainability in the UVGB by the year 2040.

Water Budgets: Foundations for Effective Water-Resources and Environmental Management

U.S. Geological Survey (USGS) | August 30th, 2007

Water budgets provide a means for evaluating availability and sustainability of a water supply. A water budget simply states that the rate of change in water stored in an

Water budgets provide a means for evaluating availability and sustainability of a water supply. A water budget simply states that the rate of change in water stored in an area, such as a watershed, is balanced by the rate at which water flows into and out of the area. An understanding of water budgets and underlying hydrologic processes provides a foundation for effective water-resource and environmental planning and management. Observed changes in water budgets of an area over time can be used to assess the effects of climate variability and human activities on water resources. Comparison of water budgets from different areas allows the effects of factors such as geology, soils, vegetation, and land use on the hydrologic cycle to be quantified. Human activities affect the natural hydrologic cycle in many ways. Modifications of the land to accommodate agriculture, such as installation of drainage and irrigation systems, alter infiltration, runoff, evaporation, and plant transpiration rates. Buildings, roads, and parking lots in urban areas tend to increase runoff and decrease infiltration. Dams reduce flooding in many areas. Water budgets provide a basis for assessing how a natural or human-induced change in one part of the hydrologic cycle may affect other aspects of the cycle. This report provides an overview and qualitative description of water budgets as foundations for effective water-resources and environmental management of freshwater hydrologic systems. Perhaps of most interest to the hydrologic community, the concepts presented are also relevant to the fields of agriculture, atmospheric studies, meteorology, climatology, ecology, limnology, mining, water supply, flood control, reservoir management, wetland studies, pollution control, and other areas of science, society, and industry. The first part of the report describes water storage and movement in the atmosphere, on land surface, and in the subsurface, as well as water exchange among these compartments. Our ability to measure these phenomena and inherent uncertainties in measurement techniques also are discussed. The latter part of the report presents a number of case studies that illustrate how water-budget studies are conducted, documents how human activities affect water budgets, and describes how water budgets are used to address water and environmental issues.

Water Stress and a Changing San Joaquin Valley

Public Policy Institute of California (PPIC) | March 1st, 2017

The San Joaquin Valley—California’s largest agricultural region, and an important contributor to the nation’s food supply—is in a time of great change and growing

The San Joaquin Valley—California’s largest agricultural region, and an important contributor to the nation’s food supply—is in a time of great change and growing water stress. Agriculture is a leading economic driver and the predominant water user. The region’s farms and related manufacturing businesses account for 25 percent of the valley’s revenues and 16 percent of local jobs—and 89 percent of annual net water use. The latest drought underscored valley agriculture’s vulnerability to water scarcity and long-term declines in groundwater reserves. The region has a greater abundance of productive farmland than local water supplies for irrigation. In most years since the mid-1980s, groundwater has been used faster than it is being replenished (“groundwater overdraft”). Over the past three decades, overdraft has averaged nearly 2 million acre-feet per year, or 13 percent of net water use. This has contributed to increased pumping costs, dry wells, sinking lands, and declining reliability of this vital drought reserve.

Water Use in California

Public Policy Institute of California (PPIC) | April 19th, 2023

Water Year 2017: What a Difference a Year Makes

California Department of Water Resources (DWR) | October 3rd, 2022

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwate

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwater level data (not available until the end of the calendar year) should show the effects of the substantial recharge water available

Westside Subbasin Groundwater Sustainability Plan

Westlands Water District | January 23rd, 2020

Westside Subbasin Groundwater Sustainability Plan (Clarified and Amended GSP)

Westlands Water District | July 18th, 2022

Due to size, this file has been divided into 11 parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11

Due to size, this file has been divided into 11 parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11