Proc. Natl Acad. Sci USA 114, 2842–2847 (2017)


Global-scale hydrological models used to estimate hydrological characteristics — such as groundwater recharge — from climate model projections mostly assume simple uniform subsurface properties.

To investigate the implications of this simplifying assumption, Andreas Hartmann from the University of Freiburg, Germany, and co-authors investigate groundwater recharge in highly heterogeneous limestone regions of Europe, Northern Africa, and the Middle East. These areas constitute about 25% of the total land area investigated and are disproportionately important aquifer regions.

They compare simulations from two large-scale hydrological models, one accounting for subsurface heterogeneity and one using conventional assumptions of uniform subsurface conditions. Results show that heterogeneity enhances recharge rates by up to four times for present conditions and changes by up to five times under climate change. These differences in recharge rates suggest that management strategies in areas with heterogeneous subsurface features need to be adapted to account for fast transit of water into aquifers.