Impacts du changement climatique sur la gestion multi-objectif de réservoirs : cas d'étude sur le bassin versant de la Seine, France

International audienceAdaptation strategies will be needed to cope with the hydrological consequences of projected climate change. In this perspective, the management of many artificial reservoirs will have to be adapted to continue to fulfil downstream objectives (e.g. flow regulation). This study evaluates the sustainability of the management rules of the artificial reservoirs on the Seine River basin, France, under climate change scenarios. The Seine River basin at Paris (43,800 km2) has major socio-economic stakes for France, and the consequences of droughts and floods may be dramatic. In this context, four large multi-purpose reservoirs were built on the basin during the twentieth century for low-flow augmentation and flood alleviation. A hydrological modelling chain was designed to explicitly account for reservoir management rules. It was calibrated in current conditions and then fed by the outputs of seven climate models in present and future conditions, forced by the A1B IPCC scenario, downscaled using a weather-type method and statistically bias-corrected. The results show that the hydrological model performs quite well in current conditions. The simulations made in present and future conditions indicate a decrease in water availability and summer low flows, but no significant trends in high flows. Simulations also indicate that there is room for progress in the current multi-purpose management of reservoirs and that it would be useful to define proper adaptation strategies