Land Subsidence in California

Measuring and Monitoring

Measurements of land-surface elevations, aquifer-system compaction, and water levels are used to improve our understanding of the processes responsible for changes in the elevation of the land's surface.  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. Aquifer-system compaction is measured by using extensometers; these measurements have the added benefit of being depth-specific because extensometers are anchored at specific depths of interest. So, while each extensometer measures some fraction of total subsidence, the measurements can help us better understand the depths at which compaction is occurring. The most precise measurements tend to be made using spirit-leveling surveys and extensometers. The least precise measurements tend to be made by using GPS surveying, with CGPS and InSAR measurements falling somewhere in the middle with regard to preciseness.

Filter Total Items: 12
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: November 30, 2018
Status: Active

Extensometers and Compaction

Extensometers measure the compaction and expansion of the aquifer system, providing depth-specific data that can help CAWSC scientists better understand the rate, extent, and at what depths in the system subsidence is occurring. 

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
Date published: October 17, 2018
Status: Active

Land Subsidence in the San Joaquin Valley

The San Joaquin Valley is one of the most productive agricultural regions in the nation. Beginning around the 1920's, farmers relied upon groundwater for water supply. Over time, overpumping caused groundwater-level declines and associated aquifer-system compaction and land subsidence that resulted in permanent aquifer-system storage loss.

Contacts: Michelle Sneed