Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence. More than 80 percent of the identified subsidence in the United States is a consequence of human impact on subsurface water.
There are concerns that fluctuating land-surface elevations due to subsidence and uplift in the valley could cause serious operational-maintenance and design construction problems for the California Aqueduct surface-water delivery system.
Surface-water imports via the California Aqueduct in the late 1960's and early 1970's, and the associated decrease in groundwater pumping, resulted in a steady recovery of water levels and a reduced rate of compaction. During the droughts of 1976-77, 1987-92, and 2007-09, diminished deliveries of imported water prompted increased groundwater pumping to meet irrigation demands. This increased pumping resulted in water-level declines reaching near historic lows and periods of renewed compaction. Following each of these droughts, recovery to pre-drought water levels was rapid and compaction virtually ceased.
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Land Subsidence in the San Joaquin Valley
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Selected USGS California Land Subsidence Publications
Land subsidence along the California Aqueduct in west-central San Joaquin Valley, California, 2003–10
Water availability and land subsidence in the Central Valley, California, USA
Land subsidence along the Delta-Mendota Canal in the northern part of the San Joaquin Valley, California, 2003-10
Groundwater availability of the Central Valley Aquifer, California
Below are data or web applications associated with this project.
Central Valley: Drought Indicators
During the recent droughts of 2007-2010 and 2012-2017, groundwater pumping has increased from the combined effects of the drought and land-use changes, re-initiating land subsidence. In order to document historical subsidence and monitor continued changes, the USGS has gathered and interpreted data from a variety of sources.
Below are news stories associated with this project.
- Overview
Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence. More than 80 percent of the identified subsidence in the United States is a consequence of human impact on subsurface water.
Map showing estimated regions of subsidence derived from interferograms for 2008–2010 and selected surface-water conveyance infrastructure in the San Joaquin Valley area of the Central Valley, California. (Public domain.) There are concerns that fluctuating land-surface elevations due to subsidence and uplift in the valley could cause serious operational-maintenance and design construction problems for the California Aqueduct surface-water delivery system.
Surface-water imports via the California Aqueduct in the late 1960's and early 1970's, and the associated decrease in groundwater pumping, resulted in a steady recovery of water levels and a reduced rate of compaction. During the droughts of 1976-77, 1987-92, and 2007-09, diminished deliveries of imported water prompted increased groundwater pumping to meet irrigation demands. This increased pumping resulted in water-level declines reaching near historic lows and periods of renewed compaction. Following each of these droughts, recovery to pre-drought water levels was rapid and compaction virtually ceased.
- Science
Below are other science projects associated with this project.
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. - Multimedia
Below are multimedia items associated with this project.
- Publications
Selected USGS California Land Subsidence Publications
Land subsidence along the California Aqueduct in west-central San Joaquin Valley, California, 2003–10
Extensive groundwater withdrawal from the unconsolidated deposits in the San Joaquin Valley caused widespread aquifer-system compaction and resultant land subsidence from 1926 to 1970—locally exceeding 8.5 meters. The importation of surface water beginning in the early 1950s through the Delta-Mendota Canal and in the early 1970s through the California Aqueduct resulted in decreased groundwater pumWater availability and land subsidence in the Central Valley, California, USA
The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern tLand subsidence along the Delta-Mendota Canal in the northern part of the San Joaquin Valley, California, 2003-10
Extensive groundwater withdrawal from the unconsolidated deposits in the San Joaquin Valley caused widespread aquifer-system compaction and resultant land subsidence from 1926 to 1970—locally exceeding 8.5 meters. The importation of surface water beginning in the early 1950s through the Delta-Mendota Canal and in the early 1970s through the California Aqueduct resulted in decreased pumping, initiaGroundwater availability of the Central Valley Aquifer, California
California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the - Web Tools
Below are data or web applications associated with this project.
Central Valley: Drought Indicators
During the recent droughts of 2007-2010 and 2012-2017, groundwater pumping has increased from the combined effects of the drought and land-use changes, re-initiating land subsidence. In order to document historical subsidence and monitor continued changes, the USGS has gathered and interpreted data from a variety of sources.
- News
Below are news stories associated with this project.