California Subsidence and Groundwater Levels

The purpose of this map is to summarize recent and historical subsidence and estimate the potential for future subsidence. Specifically, the following documentation and associated interactive map is intended to be used as a screening tool to identify areas where the potential for subsidence due to groundwater extraction may persist and to act as a guide to focus future site-specific subsidence studies.
Click on features in the map or see below for more information:

Active Extensometers:This layer depicts the location and approximate trends (subsiding or not subsiding) of 27 active extensometers, monitored by DWR, USGS, and local agencies.For more detailed information see the summary report: Summary Report

CGPS Cumulative Subsidence:This layer depicts the location and cumulative subsidence at continuous GPS stations that have subsiding trends. (http://pbo.unavco.org/, accessed 4/30/2014).For more detailed information see the summary report: Summary Report

Subsidence Trends:This layer depicts the location and approximate trend (subsiding or not subsiding) of the vertical displacement data from 319 CGPS stations within groundwater basins. (http://pbo.unavco.org/, accessed 4/30/2014).For more detailed information see the summary report: Summary Report

Change in Groundwater Level: Groundwater level data from wells was used only if the period of record was 10 years or more (long-term monitoring wells). Data from all types of wells (ag production, M&I; production, and monitoring wells were used).In addition, data from all wells were used, regardless of well depth. Groundwater data were compiled and analyzed from the California Statewide Groundwater Elevation Monitoring (CASGEM) Program and the Water Data Library (WDL) groundwater level database as of May 19th, 2014. For more detailed information see the summary report: Summary Report

Reported Subsidence Location: A comprehensive review of historical areas of subsidence as well as new areas experiencing subsidence was recently completed by LSCE, Borchers and Carpenter (2014).For more detailed information see the LSCE report LSCE Report orsummary report: Summary Report

Large Areas of Subsidence: A comprehensive review of historical areas of subsidence as well as new areas experiencing subsidence was recently completed by LSCE, Borchers and Carpenter (2014).For more detailed information see the LSCE report LSCE Report orsummary report: Summary Report

Estimated Potential Subsidence:This layer depicts the Estimated Potential for Future Land Subsidence in California in each groundwater basin.For more detailed information see the summary report: Summary Report