Impact of climate change on groundwater availability in Germany (GW_Impact)

To investigate the increasing spatio-temporal variability of groundwater recharge in the future, both locally and regionally, and its specific effects on groundwater resources in Germany, local numerical groundwater models from different regions of Germany are used and calculated with different climate projections and the associated changes in groundwater recharge.

The hot and dry summers of recent years and their impact on water supply have brought climate change to the attention of the German water industry and society. Scientific studies on the effects of climate change show that the natural water cycle will continue to change in the future, posing major challenges for water management. While climate simulations show a clear upward trend in temperature and heat indicators in the future, they also show both increases and decreases in annual precipitation. According to the climate study of the Helmholtz Centre for Environmental Research (UFZ), the most probable development (median of the scenario ensembles) for Germany is a slight increase in annual precipitation and an associated slight increase in mean annual runoff and groundwater recharge. However, the duration and intensity of dry periods will increase and the duration of the groundwater recharge period will decrease.

The GW_Impact project will select several model regions representative for Germany and run and analyse groundwater models with standardized climate input data in order to translate scenarios of future climate change impacts, in particular on groundwater recharge, into forecasts of groundwater levels and availability. The model results will then be harmonized and analyzed with regard to the derivability of general statements, e.g. depending on aquifer type, region and climate. These results will provide a basis for decision-making on adaptation to climate change for the participating German water utilities, as well as information on the expected impacts of climate change in Germany as a whole.