Land Subsidence in California

Sustainable Groundwater Management Act (SGMA)

In 2014, the State of California adopted historic legislation to help manage its groundwater, the Sustainable Groundwater Management Act (SGMA) . According to the act, local Groundwater Sustainability Agencies (GSAs) must be formed for all high and medium priority basins in the state. These GSAs must develop and implement Groundwater Sustainability Plans (GSPs) for managing and using groundwater without causing undesirable results: significant groundwater-level declines, groundwater-storage reductions, seawater intrusion, water-quality degradation, land subsidence, and surface-water depletions; these are also referred to as sustainability indicators.

Filter Total Items: 15
Date published: January 30, 2019
Status: Completed

Cuyama Valley Water Availability Study

Currently, groundwater is the only source for domestic, agricultural and municipal water use in the Cuyama Valley groundwater basin in Santa Barbara County, California. Groundwater withdrawals, mainly to irrigate agricultural crops, have resulted in water-level declines of as much as 300 feet in the area since the 1940s. To plan for sustainable future use of the groundwater, the U.S....

Contacts: Claudia C Faunt
Date published: December 18, 2018
Status: Active

Water-Level, Water-Quality and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins

Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273,000 in 1990 (...

Date published: December 13, 2018
Status: Active

Continuous Global Positioning System (CGPS) Stations

Measurements of elevations, aquifer-system compaction, and water levels are used to improve our understanding of the processes responsible for land-surface elevation changes. Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using continuous GPS (CGPS) measurements and campaign global positioning system (GPS) surveying. ...

Contacts: Michelle Sneed
Date published: December 7, 2018
Status: Active

Spirit Leveling

Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using interferometric synthetic aperture radar (InSAR), continuous GPS (CGPS) measurements, campaign global positioning system (GPS) surveying, and spirit-leveling surveying. The most precise measurements tend to be made using spirit-leveling surveys and extensometers. 

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Contacts: Michelle Sneed
Date published: December 7, 2018
Status: Active

Interferometric Synthetic Aperture Radar (InSAR)

Interferometric Synthetic Aperture Radar (InSAR) is an effective way to measure changes in land surface altitude. InSAR makes high-density measurements over large areas by using radar signals from Earth-orbiting satellites to measure changes in land-surface altitude at high degrees of measurement resolution and spatial detail (Galloway and others, 2000).

Synthetic Aperture...

Contacts: Michelle Sneed
Date published: December 6, 2018
Status: Completed

Land Subsidence in the Santa Clara Valley

Throughout the late 1800s and into the 1920s when two thirds of the Santa Clara Valley had been irrigated, water flowed freely from wells. Water-level declines of more than 200 ft occurred in the Santa Clara Valley from the early 1900's to the mid 1960's (Fowler, 1981). Land subsidence was first detected in 1933 (...

Contacts: Michelle Sneed
Date published: November 7, 2018
Status: Active

Mojave Land-Subsidence Studies

Land subsidence has been ongoing in the dry lake beds throughout the Mojave and Morongo groundwater basins since the 1960s. In a study conducted from 2004 - 2009, continuous GPS stations were added to interferometric synthetic aperture radar (InSAR) methods to measure changes in land surface altitude.

Date published: November 7, 2018
Status: Active

Land Subsidence in the Coachella Valley

Groundwater is an important water-supply source in the Coachella Valley. The demand for water has exceeded the deliveries of imported surface water, and groundwater levels have been declining as a result of increased pumping. A network of GPS stations has been set up in the valley to monitor subsidence resulting from declining groundwater levels.

Contacts: Michelle Sneed
Date published: November 6, 2018
Status: Active

Delta-Mendota Canal: Using Groundwater Modeling to Analyze Land Subsidence

A numerical modeling approach was used to quantify groundwater conditions and land subsidence spatially along the Delta-Mendota Canal. In addition, selected management alternatives for controlling land subsidence were evaluated.

Date published: November 5, 2018
Status: Completed

Delta-Mendota Canal: Evaluation of Groundwater Conditions and Land Subsidence

In areas adjacent to the Delta-Mendota Canal (DMC), extensive groundwater withdrawal from the San Joaquin Valley aquifer system has caused areas of the ground to sink as much as 10 feet, a process known as land subsidence. This could...

Date published: October 22, 2018
Status: Completed

Piezometers and Groundwater Levels

Measurements of elevations, aquifer-system compaction, and water levels are used to improve our understanding of the processes responsible for land-surface elevation changes. Elevation or elevation-change measurements are fundamental to monitoring land subsidence.

Contacts: Michelle Sneed
Date published: October 19, 2018
Status: Completed

Simulating Land Subsidence

The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.

Contacts: Claudia C Faunt