Groundwater Depletion in the United States (1900−2008)
Leonard F. Konikow. Scientific Investigations Report 2013-5079 U.S. Geological Survey, Reston, VA, 2013
This USGS study evaluated absolute changes in storage for 40 major aquifers between 1900 and 2008. The study shows that the rate of groundwater depletion has increased markedly since about 1950. Maximum depletion rates occurred from 2000 to 2008 at three times the rate of depletion for the entire study time frame. In total, groundwater reserves decreased by nearly 1,000 cubic kilometers, or twice the amount of water in Lake Erie. Yet, aquifers in the Pacific Northwest – the Columbia Plateau and the Snake River Plain aquifers – actually saw a net increase in storage after 1900 due to imported river water for irrigation. Since the late 1970s, however, both have been declining. The reverse is true in Arizona, where groundwater reserves have increased since 1980 because of stricter management and new surface water supplies from the Colorado River.