Calculating recharge of groundwater more precisely

A team of international researchers led by University of Freiburg hydrologist Dr. Andreas Hartmann suggests that inclusion of currently missing key hydrological processes in large-scale climate change impact models can significantly improve our estimates of water availability.
The study shows that groundwater recharge estimates for 560 million people in karst regions in Europe, the Middle East and Northern Africa, are much higher than previously estimated from current large-scale models.
The team has published their research findings in the scientific journal Proceedings of the National Academy of Sciences (PNAS).
Groundwater is a vital resource in many regions around the globe.
The researchers have compared two hydrological models that simulate groundwater recharge.
One is a long-established global model with limited accounting for subsurface heterogeneity.
The other is a continental model the researchers have developed themselves that includes, for example, variability in the thickness of soils and different subsurface permeabilities.
A comparison of the models’ calculations with independent observations of groundwater recharge at 38 sites in the regions has shown that the model that accounts for heterogeneity produces more realistic estimates.
The researchers explain the reason for the difference between the two models as follows: In simulation, their newly developed model shows reduced fractions of surface According to the new model, a farmer in the Mediterranean region would potentially have up to a million liters more groundwater for extraction available in a year than the established model estimates, dependent on actual subsurface composition and the water demands of the local ecosystems.
Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity.

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