Which is the reason for the land subsidence in the San Joaquin Valley in California?
Land subsidence caused by groundwater pumping has been observed in the San Joaquin Valley for decades. Increased reliance on aquifers during the last decade resulted in subsidence rates in excess of a foot per year in some parts of the region.
Where is most of the land subsidence occurring in California?
San Joaquin Valley
Half of all of the subsidence that has occurred in the United States has occurred in California. The most severely affected areas were in southern and western portions of the San Joaquin Valley as irrigated agriculture expanded.
What caused land subsidence in the San Joaquin Valley of California What impact did it have on the aquifer?
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.
What happened in the San Joaquin Valley of California as the result of excessive groundwater withdrawal?
The withdrawal of groundwater near Lucerne Lake (dry) in San Bernardino County, Mojave Desert, California has caused the land to subside, with the results being the formation of fissures on the landscape. In some instances, the fissures were more than 1 meter (3.3 feet) wide and deep.
How fast is the valley sinking?
In rolling out the research, the California Department of Water Resources said, “Land in the San Joaquin is sinking faster than ever before, nearly two inches per month in some locations.” And while subsidence can have a number of causes, the San Joaquin is sinking because more water is being pumped out of the …
How bad is subsidence in California?
Land subsidence can damage critical infrastructure, including water delivery systems, levees, roads, and bridges. In 2017, DWR worked with NASA to release a report on San Joaquin Valley subsidence citing areas along the California Aqueduct that have experienced almost two feet of subsidence over three years.
Is the California valley sinking?
California’s Central Valley subsides when groundwater is pumped faster than underground aquifers can be recharged. The Central Valley has been sinking at differing rates since the 1920s and is estimated to have sunk up to 28 feet.
What happens when air subsides?
Subsidence, or sinking of air, may happen instead, forming an area of high pressure, an anticyclone. Warming of the air as it subsides increases evaporation, causing clear skies. That is why high pressure systems are usually associated with fair weather.
Is California Central Valley sinking?
What was cause of subsidence in San Joaquin Valley?
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.
Is the San Joaquin Valley in California unsustainable?
“The rates of San Joaquin Valley subsidence documented since 2014 by NASA are troubling and unsustainable,” said DWR Director William Croyle. “Subsidence has long plagued certain regions of California. But the current rates jeopardize infrastructure serving millions of people.
How did the importation of water affect the San Joaquin Valley?
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 pumping, recovery of water levels, and a reduced rate of compaction in some areas of the San Joaquin Valley.
Where is the subsidence of the California Aqueduct?
The U.S. Geological Survey, in cooperation with the California Department of Water Resources, assessed more recent land subsidence near a 145-kilometer reach of the California Aqueduct in the west-central part of the San Joaquin Valley as part of an effort to minimize future subsidence-related damages to the California Aqueduct.