In the context of global warming, hydrological regimes in mountain areas
are likely to be modified and will therefore result in significant
impacts to the supply mechanisms for hydropower and other end-uses of
water, both in the mountains themselves and in the lowland regions
downstream. The main objective here is to attempt a fine and continuous
analysis of the impacts of such changes on runoff and glaciers in a
largely ice-covered catchment in the Swiss Alps: the Findelen watershed.
The simulated daily discharge values have been obtained with a
semi-distributed hydrological model called Routing System 3 (RS3.0). A
stochastic weather generator has been used to generate a 110 year
sequence of meteorological input datadescribed in a companion
articlethat have been further perturbed in order to simulate a
progressively warmer climate by the end of the century. The amplitude of
atmospheric change is suggested by regional climate model simulations,
under the A2 greenhouse-gas emissions scenario. Results show at first an
increase of discharge (19.4% in about 60 years) due to the rapid melt
of the glacier, followed by a large decrease in runoff at the end of the
period (28% from the beginning to the end of the studied timeframe),
primarily due to the depletion of the solid water reservoir. The glacier
is indeed projected to lose 91% of its surface area. In parallel, a
seasonal shift in flow patterns is also observed: the discharge values
are high earlier in spring due to advanced snow and ice melt, while the
rest of the curve flattens out. Copyright (c) 2012 Royal Meteorological
Society