This image shows umulative groundwater losses (cubic km and million acre-ft) in California's Central Valley since 1962. The red line shows data from USGS calibrated groundwater model simulations from 1962-2003. The green line shows satellite-based estimates of groundwater storage losses produced by the UCCHM at UC Irvine. Background colors represent periods of drought (white), of variable to dry conditions (grey), of variable to wet conditions (light blue) and wet conditions (blue). Groundwater depletion mostly occurs during drought; and progressive droughts are lowering groundwater storage to unsustainable levels. After Figure B9 from USGS Professional Paper 1766. USGS data courtesy of Claudia Faunt. Satellite data courtesy of NASA and the National Center for Atmospheric Research.
Figure credit: Figure by UCCHM, after Figure B9 from Faunt, 2009. USGS data courtesy of Claudia Faunt.