Global scale groundwater analyses: An invisible part of the Earth System

Fig. 1: Top) Simulated average water table depths (averaged for the period 1960–2010) in meters below the land surface on the upper aquifer under natural conditions (without human water withdrawal) for the maximum confining scenario and the best parameter set. Bottom) head different; heads in bottom minus top layer. For water under pressure in the confined aquifer (bottom layer) a positive value is shown. When heads in the confining layer are higher, negative values are shown Quelle: de Graaf et al., 2017