Peak groundwater depletion in the High Plains Aquifer, projections from 1930 to 2110

Peak groundwater depletion from overtapping aquifers beyond recharge rates occurs as the depletion rate increases until a peak occurs followed by a decreasing trend as pumping equilibrates towards available recharge. The logistic equation of Hubbert's study of peak oil is used to project measurements at a set of observation wells, which provide estimates of saturated thickness and changes in groundwater storage from 1930 to 2110. The annual rate of depletion in High Plains Aquifer of the central USA is estimated to have peaked at 8.25 x 10(9) m(3)/yr in 2006 followed by projected decreases to 4.0 x 10(9) m(3)/yr in 2110. The timing of peaks follows a south-north progression, with peaks occurs in 1999 for Texas, 2002 for New Mexico, 2010 for Kansas, 2012 for Oklahoma and 2023 for Colorado; peaks do not occur before 2110 for Nebraska, South Dakota and Wyoming. The manifestation of peak groundwater depletion contributes towards the more comprehensive understanding necessary to assess potential vulnerabilities in the water-food nexus posed by aquifer depletion. (C) 2015 The Authors. Published by Elsevier B.V.