Land Subsidence Along the California Aqueduct
Science Center Objects
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.
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Date published: October 17, 2018Status: ActiveLand 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
Water 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,...
Faunt, Claudia C.; Sneed, Michelle; Traum, Jonathan A.; Brandt, Justin T.
Land 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...
Sneed, Michelle; Brandt, Justin T.; Solt, Mike
Groundwater 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...
Faunt, Claudia C.-
Date published: November 1, 2016Central 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.
California Aqueduct, San Joaquin Valley
The California Aqueduct flowing near Huron, CA in the San Joaquin Valley. This spot is near one of several USGS land subsidence monitoring stations in the San Joaquin Valley. Land subsidence has reduced the conveyance capacity of the Aqueduct and other water
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California Aqueduct - Central Valley
California Aqueduct through San Joaquin Valley, CA (2006)
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Date published: March 16, 2017Extensometer Hunters: Searching for Long-Lost Technologies in San Joaquin Valley
San Joaquin Valley: the final frontier. These are the voyages of the U.S. Geological Survey. Its weeklong mission: to explore strange new locations, to seek out abandoned scientific technologies, to boldly go where no scientist has gone before (at least in a few decades).