California's Central Valley Groundwater Wells Run Dry During Recent Drought

American Geophysical Union (AGU) | February 27th, 2020

Declining water tables are causing wells to run dry in California, but the prevalence and spatial distribution of wells that have run dry are not known beyond anecdotal a

Declining water tables are causing wells to run dry in California, but the prevalence and spatial distribution of wells that have run dry are not known beyond anecdotal and voluntary reports. Here, we apply a new, simple, and measurement‐driven method to calculate a localized water table; we show, for the first time using observations, that up to one‐in‐five wells now runs dry in California's Central Valley. The spatial distribution of wells identified as having dried up replicates hot spots of wells identified as having run dry in a voluntary reporting system, while also capturing impacts on groundwater wells that have not reportedly run dry. We assess the rates of drilling throughout the Central Valley and find, surprisingly, that domestic wells are being drilled deeper at a rate that exceeds agricultural wells across much of the central Central Valley. Because new groundwater wells are costly (i.e., $10,000 to $100,000), we suggest explicitly considering dry wells in groundwater sustainability planning to protect homes and farms from the loss of access to reliable water supplies in the future.

California's Future

Public Policy Institute of California (PPIC) | January 18th, 2018

Water management in California has always been challenging. The state’s variable climate is marked by long droughts and severe floods, with stark regional differences i

Water management in California has always been challenging. The state’s variable climate is marked by long droughts and severe floods, with stark regional differences in water availability and demand. California has adapted by building a vast network of storage and conveyance facilities to deliver water from the wetter parts of the state to population and farming centers in the Bay Area, the San Joaquin Valley, and Southern California. The Sacramento–San Joaquin Delta is a fragile link in the state’s water supply network, and a plan to address supply reliability, known as California WaterFix, faces many hurdles. California’s extensive network of dams is aging. Agricultural demand is becoming less flexible, as farmers are increasing tree crops (especially nuts), which must be watered every year. Conflicts are growing between human water use and water needed to support fish and other wildlife. And the latest cycle of droughts and floods provides a glimpse of an uncertain future under climate change. California’s water management challenges are complex, but they can be addressed. Solutions will involve difficult and sometimes costly trade-offs, as well as contentious legal and political changes.

California's Groundwater Conditions Semi-Annual Update: March 2023

California Department of Water Resources (DWR) | March 15th, 2023

These updates are part of the informational resources associated with DWR’s California’s Groundwater (Bulletin 118). This report uses groundwater data received electr

These updates are part of the informational resources associated with DWR’s California’s Groundwater (Bulletin 118). This report uses groundwater data received electronically by DWR as of February 15, 2022, through the conclusion of Water Year 2022, and the start of Water Year 2023.

California's Groundwater Conditions: Semi Annual Update May 2024, Spring Bulletin 118

California Department of Water Resources (DWR) | May 6th, 2024

In WY 2023, increased surface water supply led to a significant reduction in statewide groundwater extraction, amounting to a total annual extraction of 9.5 million acre-

In WY 2023, increased surface water supply led to a significant reduction in statewide groundwater extraction, amounting to a total annual extraction of 9.5 million acre-feet, a stark contrast to the 17 million acre-feet extracted in WY 2022.

California's Groundwater Conditions: Semi-Annual Update May 2025

California Department of Water Resources (DWR) | June 24th, 2025

This semi-annual report presents data received by DWR as of April 2025 and reflects the impacts of a few wet years after a drought period. However, it should be noted tha

This semi-annual report presents data received by DWR as of April 2025 and reflects the impacts of a few wet years after a drought period. However, it should be noted that groundwater response is a slow process and may take months to years to fully respond to changes in surface water conditions. This report is the latest in a series of Semi-Annual Groundwater Conditions Updates, last published in October 2024. These updates are part of the informational resources associated with DWR’s California’s Groundwater (Bulletin 118). The most recent groundwater data is available on the California’s Groundwater Live website, which is updated daily as data is received by DWR. Additional data and information are available in the CNRA Open Data and Water Data Library websites.

California's Water Supply Strategy: Adapting to a Hotter, Drier Future

California Department of Water Resources (DWR) | August 16th, 2022

California’s Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California’s Central Valley

U.S. Geological Survey (USGS) | June 16th, 2009

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley’s population has nearly

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley’s population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento–San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource. The U.S. Geological Survey (USGS) has released results from a study on the largest water reservoir in the State of California, the Central Valley groundwater system. The findings show continued loss of stored groundwater in the southern part of the valley (see figure below). Since about 1960, groundwater has been depleted by almost 60 million acre-feet, which is, on average, enough to supply every resident of California with water for 8 years. In order to complete the study, the USGS developed an extensive, detailed three-dimensional (3D) computer model of the hydrologic system of the Central Valley (Faunt, 2009). The Central Valley Hydrologic Model (CVHM) simultaneously accounts for changing water supply and demand across the landscape, and simulates surface water and groundwater flow across the entire Central Valley. This new hydrologic modeling tool can be used by water managers to understand how water moves through the aquifer system, predict water-supply scenarios, and address issues related to water competition in California and the Central Valley including: Conjunctive water use (interdependent use of surface water and groundwater); Conservation of agricultural land; Land-use change, including environmental concerns and urbanization, and its effects on water resources; and Effects of climate change.

California’s Groundwater Conditions Semi-Annual Update: October 2022

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

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Wat

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Water Year 2022 groundwater data used in this report includes data received electronically by DWR as of August 31, 2022.

California’s Groundwater Conditions: Semi-Annual Update, October 2023, Fall Bulletin 118 Information Update

California Department of Water Resources (DWR) | October 12th, 2023

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquife

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquifer recharge. However, it should be noted that groundwater response is a slow process and takes months to years to fully respond to changes in surface water conditions.

California’s groundwater overdraft: An environmental Ponzi scheme?

Journal of Hydrology (Elsevier) | January 23rd, 2023

Groundwater levels have been decreasing in most agricultural areas, motivating research to find optimal solutions to balance socio-economical and environmental demands. T

Groundwater levels have been decreasing in most agricultural areas, motivating research to find optimal solutions to balance socio-economical and environmental demands. Traditionally, groundwater optimization aims at long-term profit maximization, while accounting for the extraction costs. Following this approach, we find exploitation protocols characterized by pumping rates that slowly decrease in time toward a long-term sustainable value. However, the comparison of the model prediction with water extraction data for the period 1985–2021 from Kern County in California points out the inconsistencies between real management and long-term optimal behavior. Rather, the observed trajectory resembles those obtained by finite-time optimization horizons, which provide short-term high profits by over-drafting, while leading to long-term dilapidation of the capital and the exhaustion of the aquifer. Such myopic planning results in a Ponzi scheme for groundwater extraction. Like the infamous fraudulent scheme, ‘more-than-optimal’ profits are achievable by excessive short-term consumption by the early investors (the past and current aquifer exploiters), leaving the later comers (the future generations) with an impossible cost to sustain. Including the environmental costs of aquifer over-exploitation, the myopic nature of human planning can be corrected and reconciled with a more sustainable use of groundwater.