Groundwater Footprint
"The area required to sustain groundwater use and dependent ecosystems" (Gleeson et al. 2012)
Sources
Gleeson, Tom, Yoshihide Wada, Marc FP Bierkens, and Ludovicus PH Van Beek. "Water balance of global aquifers revealed by groundwater footprint." Nature 488, no. 7410 (2012): 197-200.