Groundwater recharge under scenario conditions

Abstract

Although the Upper Danube region is currently not suffering under water scarcity and thus the availability of drinking water is not a key issue, it is important to investigate the potential impacts of climate change on groundwater recharge in the Upper Danube drainage, because more than 90 % of the drinking water in this region is sourced from groundwater. Therefore, all of the climate scenarios of the GLOWA-Danube project, including their four statistical climate variants, as well as the climate variants of the REMO downscaled and bias-corrected and MM5 downscaled and bias-corrected regional climate models for the Upper Danube basin were calculated with the DANUBIA model framework. This resulted in a total of 18 model scenario runs which all show a significant decrease in GWR particularly in the summer months due to the climate change-induced decline of rainfall and higher evapotranspiration rates in the summer. For example, the proportion of the total annual groundwater recharge in the summer months is approximately 29 % for the reference period and will decline to 17 % based on the REMO regional-Baseline scenario. The predicted decrease in GWR for the period 2011-2060 fluctuates between 33 and 125 mm. The results of DANUBIA show that there is a significant change in GWR due to climate change in the Upper Danube region based on the model scenarios.