Pajaro Valley Water Management Agency Revised Management Plan

Pajaro Valley Water Management Agency (PVWMA) | February 14th, 2002

Paso Robles Subbasin Groundwater Sustainability Plan

Paso Robles Subbasin Cooperative Committee | November 13th, 2019

Pixley Irrigation District Groundwater Sustainability Plan

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | January 21st, 2020

Pixley Irrigation District Groundwater Sustainability Plan (Revised)

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | July 27th, 2022

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimat

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimated annual average overdraft within the Tule Subbasin is 70,000 acre-feet per year. The overdraft conditions have caused issues for those reliant on groundwater pumping, which include municipal, domestic, and agriculture users. Other issues generated from the overdraft include areas of land subsidence, which predominantly occur in the northwestern portion of the Agency. A sample of the Pixley GSP is displayed below. Due to size, this full 2,421-page document must be downloaded from the Department of Water Resources.

Post-Drought Groundwater Storage Recovery in California's Central Valley

American Geophysical Union (AGU) | October 5th, 2021

California's Central Valley has experienced chronic groundwater depletion over the past few decades, the rate of which was amplified by droughts in 2007–2009 and 2012â€

California's Central Valley has experienced chronic groundwater depletion over the past few decades, the rate of which was amplified by droughts in 2007–2009 and 2012–2016. There is limited knowledge as to how much of the drought-caused groundwater depletion has recovered during post-drought years and how climate and water management affect overdraft recovery times. We address these issues by estimating groundwater storage changes using four methods and conducting numerical experiments with varying climatic conditions and water management options. We find that less than one-third of the groundwater overdraft from the most recent droughts was recovered during post-drought years. Projected overdraft recovery times vary greatly depending on the climate scenarios and water management strategies, and future droughts are likely to cause overdrafts from which recovery is unlikely given the current level of groundwater extractions. However, management measures such as capping groundwater pumping could reduce recovery times by a factor of two or more depending on the groundwater extraction cap and post-drought climate.

Potential Effects of Groundwater Pumping on Water Levels, Phreatophytes, and Spring Discharges in Spring and Snake Valleys, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

U.S. Geological Survey (USGS) | March 18th, 2011

Potential Impacts of Future Geological Storage of CO2 on the Groundwater Resources in California’s Central Valley: Southern San Joaquin Basin Oil and Gas Production Analog for Geologic Carbon Storage

California Energy Commission (CEC) | May 1st, 2013

This study investigated the potential impacts of the injection and storage of large quantities of carbon dioxide on shallow water resources in California’s southern San

This study investigated the potential impacts of the injection and storage of large quantities of carbon dioxide on shallow water resources in California’s southern San Joaquin Basin, including the possibility that if such injection was properly planned it might help mitigate the land subsidence impacts related to over-pumping of groundwater. The project used simulation studies to investigate whether the basin-scale pressure changes and brine displacement caused by future carbon dioxide storage in the deep sediments could impact the groundwater-surface water systems in the area. Two simulation models were developed. The Deep Basin Reservoir Simulation Model was developed for accurately simulating the multiphase processes of carbon dioxide and brine flow occurring in deep sequestration reservoirs. The Shallow Water Resources Impact Simulation Model was developed for accurately predicting the impact of deep carbon dioxide sequestration on a stressed water system, including evaluation of carbon dioxide-related impacts in the context of the long-term groundwater and subsidence trends occurring in the area as a result of other water stresses such as pumping and irrigation. The Deep Basin Reservoir Simulation Model showed that the caprock and overlying geological units had sufficient barrier attributes to prevent pressure propagation from the injection layer to the shallow aquifers. The Shallow Water Resources Impact Simulation Model simulation results showed that deep carbon dioxide injection would create only minor head change and surface uplift in the shallow model layers. Overall the simulation results suggested that even large carbon dioxide storage projects should have minimal impact on shallow groundwater and surface water systems if thick layers of shales and sands separated the deep CO2 injection layers from shallow aquifers. Researchers believed this study justified devoting resources to evaluating the potential impact from localized pathways or from induced seismicity to more thoroughly investigate the feasibility of carbon dioxide storage in the southern San Joaquin Basin. 

Preliminary Evaluation of Impacts of Potential Groundwater Sustainability Indicators on Future Groundwater Extraction Rates – Oxnard Plain and Pleasant Valley Groundwater Basins

United Water Conservation District (UWCD) | April 4th, 2017

This evaluation was performed to estimate the combined sustainable yield of the Oxnard Plain (including the Forebay) and Pleasant Valley groundwater basins (the study are

This evaluation was performed to estimate the combined sustainable yield of the Oxnard Plain (including the Forebay) and Pleasant Valley groundwater basins (the study area). The purpose is to provide supporting information to United Water Conservation District’s (United) management and Board of Directors in establishing groundwater management policies that are consistent with the mission of the agency. United recognizes that the compliance actions associated with the Sustainable Groundwater Management Act (SGMA), the formation of a Groundwater Sustainability Agency (GSA), and the creation and implementation of Groundwater Sustainability Plans (GSPs) have the potential to change how groundwater resources are managed in Ventura County. This report was prepared for the benefit of United’s Board of Directors and senior management, and is not intended to serve as a GSP, define how the sustainable yield should be determined by the GSA, or specify what value or range of values should be used as the sustainable yield. The analyses and results are meant to be used as a starting point in evaluating potential impacts to United’s operations as a result of sustainability planning already underway by the Fox Canyon Groundwater Management Agency (FCGMA) for the study area. Note: an addendum to this was published on November 7, 2017

Preliminary Evaluation of the Hydrogeologic System in Owens Valley, California

U.S. Geological Survey (USGS) | January 8th, 1988

Owens Valley is a major source of water for southern California and presently (1986) provides more than 60 percent of the supply for Los Angeles. Since 1970, ground-water

Owens Valley is a major source of water for southern California and presently (1986) provides more than 60 percent of the supply for Los Angeles. Since 1970, ground-water withdrawal from Owens Valley has increased, and a decline in the health of vegetation has been reported. In 1982, a cooperative project to study the hydrogeology and plant ecology of Owens Valley was begun by Inyo County, the Los Angeles Department of Water and Power, and the U.S. Geological Survey. As part of this project, the available data and present hydrologic concepts of Owens Valley were evaluated by using a ground-waterflow model. Results of this preliminary evaluation are being used to guide data collection and the development of more sophisticated hydrologic models.

Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

U.S. Geological Survey (USGS) | July 19th, 2017