Scenarios for the Development of Floods in the Upper Danube Basin

Abstract

The projected future impact of climate change on flood peak discharge and return period in the Upper Danube basin is analysed for a broad range of climate change scenarios based in a stochastic climate generator or on results of regional climate simulations. The analysis was carried out from 2011 to 2060 for the outlet gauge at Achleiten and for the two adjacent gauges in the main tributaries. In addition, the spatial distribution of the 100-year return period annual peak discharge was analysed. The result for the outlet gauge of the Upper Danube shows no significant changes of annual peak discharges with climate change until 2060. This is the result from a complex interaction of a slight decrease in the Alpine forelands and an increase in the Inn, which originates in the Alps. Spatially large increases of flood peaks in the Alpine headwaters, which are caused by rainfall-induced snowmelts, contrast with decreases in flood peaks in the forelands. The results are summarised in three key statements.