Remote sensing of climate and management driven groundwater storage changes and land subsidence in the Central Valley, CA

The Gravity Recovery And Climate Experiment (GRACE) reveals a significant negative trend in total water storage for the Central Valley of California for the time period Nov 2003-March 2009. The human fingerprint was separated from the total water storage trend in GRACE using hydrologic models to account for climate driven changes in storage for the region. Supplementary observations of surface water, soil moisture, and snow water equivalent were used to vertically disaggregate total water storage and determine changes in groundwater storage. Results reveal insight on the dominant role of groundwater pumping in aquifer storage and the extension of evaporative fluxes throughout the summer growing season. Groundwater storage changes are compared with GPS observations of land subsidence in the region to determine relationships between groundwater pumping and land surface response.