Potential evolution of the Seine River flood regime under climate change

We regionalized 12 different scenarios of anthropogenic climate change in the Seine River basin, which were used as input to 5 different hydrological models. The resulting hydrological scenarios all agree on a marked depletion of the water resources during the 21. century, with an annual mean decrease in both water table level and river discharge. At the seasonal scale, the reduction of river flow is more marked on low than on high flows, the decrease of which is also less robust. The response of extreme flows is even more contrasted, and the QJXA10 high-flow quantile (annual daily maximum with an average return period of 10 years) would not change significantly during the 21. century. Our results also suggest that the 100-year flood, extrapolated using the Gradex method, would remain of the same order of magnitude as today. (authors)