Groundwater and Urban Growth in the San Joaquin Valley

Public Policy Institute of California (PPIC) | September 20th, 2021

The San Joaquin Valley is ground zero for the Sustainable Groundwater Management Act (SGMA). It has the largest groundwater deficit in California and faces some of the

The San Joaquin Valley is ground zero for the Sustainable Groundwater Management Act (SGMA). It has the largest groundwater deficit in California and faces some of the worst impacts from overdraft, including land subsidence and drying wells. SGMA will help the region address these issues—while also building its climate resilience. But this will require hard work, not only by farmers—the largest groundwater users—but also by the valley’s urban water utilities, which serve a growing population while relying mostly on groundwater. As the valley confronts limits on groundwater pumping, urban utilities, local land use authorities, other water users, and state agencies must all engage to ensure a smooth transition for the region’s residents.

Groundwater Availability within the Salton Sea Basin

Lawrence Livermore National Laboratory (LLNL) | January 29th, 2008

Groundwater Conditions Report Water Year 2021

California Department of Water Resources (DWR) | March 15th, 2022

Groundwater depletion in California’s Central Valley accelerates during megadrought

Nature Portfolio (Springer Nature) | December 19th, 2022

Groundwater provides nearly half of irrigation water supply, and it enables resilience during drought, but in many regions of the world, it remains poorly, if at all mana

Groundwater provides nearly half of irrigation water supply, and it enables resilience during drought, but in many regions of the world, it remains poorly, if at all managed. In heavily agricultural regions like California’s Central Valley, where groundwater management is being slowly implemented over a 27-year period that began in 2015, groundwater provides two–thirds or more of irrigation water during drought, which has led to falling water tables, drying wells, subsiding land, and its long-term disappearance. Here we use nearly two decades of observations from NASA’s GRACE satellite missions and show that the rate of groundwater depletion in the Central Valley has been accelerating since 2003 (1.86 km3/yr, 1961–2021; 2.41 km3/yr, 2003–2021; 8.58 km3/yr, 2019–2021), a period of megadrought in southwestern North America. Results suggest the need for expedited implementation of groundwater management in the Central Valley to ensure its availability during the increasingly intense droughts of the future.

Groundwater Depletion in the United States (1900-2008)

U.S. Geological Survey (USGS) | June 1st, 2013

A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion in the Unit

A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion in the United States are not well characterized. This study evaluates long-term cumulative depletion volumes in 40 separate aquifers or areas and one land use category in the United States, bringing together information from the literature and from new analyses. Depletion is directly calculated using calibrated groundwater models, analytical approaches, or volumetric budget analyses for multiple aquifer systems. Estimated groundwater depletion in the United States during 1900–2008 totals approximately 1,000 cubic kilometers (km3). Furthermore, the rate of groundwater depletion has increased markedly since about 1950, with maximum rates occurring during the most recent period (2000–2008) when the depletion rate averaged almost 25 km3 per year (compared to 9.2 km3 per year averaged over the 1900–2008 time-frame). 

Groundwater Discharge by Evapotranspiration, Dixie Valley, West-Central Nevada, March 2009–September 2011

U.S. Geological Survey (USGS) | April 30th, 2015

Groundwater Management and Safe Drinking Water in the San Joaquin Valley

Water Foundation | June 2nd, 2020

Groundwater Management Plan Goleta Groundwater Basin

Goleta Water District (GWD) | May 11th, 2010

Goleta Water District (“GWD”) and La Cumbre Mutual Water Company (“La Cumbre”), the purveyors of groundwater in the Goleta Groundwater Basin, joined in developing

Goleta Water District (“GWD”) and La Cumbre Mutual Water Company (“La Cumbre”), the purveyors of groundwater in the Goleta Groundwater Basin, joined in developing a Groundwater Management Plan (“Plan”) for the basin. This Plan reiterates current adjudication and voter-passed components of groundwater management, addresses groundwater issues, adopts Basin Management Objectives, outlines management strategies for the basin, and recommends future tasks and timelines associated with these tasks.

Groundwater quality data in the Mojave study unit, 2008: Results from the California GAMA Program

U.S. Geological Survey (USGS) | July 1st, 2009

Groundwater Quality in the Yuba River and Bear River Watersheds, Sierra Nevada, California

U.S. Geological Survey (USGS) | September 27th, 2017

The Yuba River and Bear River Watersheds study unit (Yuba-Bear Watersheds) covers approximately 4,400 square kilometers on the western slope of the Sierra Nevada. Groundw

The Yuba River and Bear River Watersheds study unit (Yuba-Bear Watersheds) covers approximately 4,400 square kilometers on the western slope of the Sierra Nevada. Groundwater composes about 10 percent of overall water use in the region, but is the sole supply for many individual homes beyond the limits of public water supply infrastructure (Cosumnes, American, Bear, Yuba Integrated Regional Water Management Group, 2014). Recent drought conditions highlighted the vulnerability of private wells to diminished groundwater supplies in the study area and many wells required deepening (California Department of Water Resources, 2014).