GROUNDWATER DEPLETION AS A GLOBAL PHENOMENON

Over 2 billion people rely on groundwater as their primary source of water for domestic, industrial and agricultural needs. Ironically however, monitoring groundwater use remains challenging, even in the developed world. In the developing world, it is often non-existent. Over the last decade, advances in satellite remote sensing are providing new means for monitoring groundwater storage changes in the world’s large aquifer systems. Specifically, NASA’s Gravity Recovery and Climate Experiment (GRACE) mission provides monthly data on terrestrial water storage changes (i.e. for all of the snow, surface water, soil moisture and groundwater) in regions that of at least 200,000 square kilometers. Combining GRACE data with independent observations of snow, surface water and soil moisture has proven to be an effective means of characterizing groundwater storage changes. In this presentation, the GRACE-based methodology will be reviewed, and groundwater storage changes in the world’s major aquifer systems will be presented. Current rates of groundwater depletion will be discussed in the context of a sustainable water future.