Land subsidence due to ground-water withdrawal Arvin-Maricopa area, California

The Arvin-Maricopa area is the southernmost of three principal areas of widespread subsidence in the San Joaquin Valley. As of 1970, 700 square miles of irrigable land, roughly 60 percent of the area, has subsided due to the intensive pumping of ground water. Maximum subsidence exceeds 9 feet, and the total volume of subsidence (1926-70) is about 1 million acre-feet. Subsidence results from the compaction of water-yielding deposits as intergranular stresses are increased by water-level declines. Also, scattered local areas are affected by the hydrocompaction of moisture-deficient surficial deposits and by subsidence due to the extraction of oil-field fluids.