This year, groundwater levels in many wells in California’s Central Valley are at or below historical low levels. In addition, from 2007 through 2015, land subsidence that correlates to areas with large groundwater level declines has strongly increased in two large agricultural areas near the towns of El Nido and Pixley, according to a new article by the U.S. Geological Survey.
http://www.spinics.net/lists/usgs/msg00990.html