Effect of climate change on overland flow generation: a case study in central Germany

The impact of global climate change on runoff components, especially on the type of overland flow, is of utmost significance. High-resolution temporal rainfall plays an important role in determining the hydrological response of quick runoff components. However, hydrological climate change scenario analyses with high temporal resolution are rare. This study investigates the impact of climate change on discharge peak events generated by rainfall, snowmelt, and soil-frost induced runoff using high-resolution hydrological modelling. The study area is Schafertal catchment (1.44km(2)) in the lower Harz Mountains in central Germany. The WaSiM-ETH hydrological model is used to investigate the rainfall response of runoff components under near future (2021-2050) and far-distant future (2071-2100) climatic conditions. Disaggregated daily climate variables of WETTREG2010 SRES scenario A1B are used on a temporal resolution of 10min. Hydrological model parameter optimization and uncertainty analysis was conducted using the Differential Evolution Adaptive Metropolis (DREAM_(ZS)) uncertainty tool. The scenario results show that total runoff and interflow will increase by 3.8% and 3.5% in the near future and decrease by 32.85% and 31% in the far-distant future compared to the baseline scenario. In contrast, overland flow and the number and size of peak runoff will decrease moderately for the near future and drastically for the far-distant future compared to the baseline scenario. We found the strongest decrease for soil-frost induced discharge peaks at 79.6% in the near future and at 98.2% in the far-distant future scenario. It can be concluded that high-resolution hydrological modelling can provide detailed predictions of future hydrological regimes and discharge peak events of the catchment. Copyright (c) 2014 John Wiley & Sons, Ltd.