Effects of climate change on water resources and runoff in an Alpine basin

The combined influence of increased temperatures and changed precipitation on the seasonal snow cover and runoff is evaluated for the Upper Rhine Basin at Felsberg (3250 km 2 , 560-3614 m a.s.l.). The runoff regime reflects the snow accumulation in the winter half-year and snowmelt in the summer half-year. The method of predicting future runoff regimes is based on high resolution periodical snow cover mapping by satellites. The snow coverage is the main input variable for the snowmelt runoff model SRM-ETH (version of the Institute of Technology ETH). The model computes the present runoff and the climate-affected snow-covered areas, from which it computes the future runoff. Conditions of the present climate are represented by a normalized year. Snow conditions and yearly hydrographs are evaluated for the years 2030 and 2100 according to the given climate scenarios for this region. Quantitative results indicate the decrease of the snow accumulation on 1 April as well as the seasonal redistribution and changes of runoff.