A first assessment of the impact of climate change on discharge and groundwater recharge in a catchment in Northeastern Germany

Future climate changes might have some impacts on the discharge regime regarding e.g. longer low flow periods due a decreased precipitation and higher evapotranspiration in summer months in many countries in Europe. An assessment of such impacts is required to derive adaptation strategies for future water resources management. For that purpose, in a case study, we applied a hydrological catchment model in the Ucker catchment with an area 2415 km(2) located in the Northeastern German lowlands for a first assessment of the impact of climate change on discharge regime using meteorological time series from 1951-2055. These time series were generated by the Potsdam Institute of Climate Impact Research based on the A1B-Scenario with an increase of 1.4 degrees C of the mean annual temperature in Europe. After model calibration, the comparison of simulated and observed daily discharge rates from 1989-2003 led to a Nash-Sutcliffe-Index NS = 0.63. The results of this simulation study indicated, that the amount of days with low flow conditions in the Ucker river will increase and groundwater recharge especially at forested areas will decrease in an order of magnitude of 44-94%.