Rhône floods under climate change (RhoClim)

River floods are changing in size and frequency with climate change. This also affects the Rhône in Switzerland. A better understanding of the frequency of floods and the processes that trigger them under changing climate conditions is essential to develop sustainable adaptation measures for floods in the Rhône. However, the quantification of flood characteristics under future climate conditions poses a challenge because floods exhibit large interannual variability and are among other processes caused by localised intense precipitation, which is not optimally represented in climate simulations. To quantify this variability and identify significant long-term changes in different flood types, large and high-resolution simulation ensembles are required. These are available via Single Model Initial condition Large Ensembles (SMILEs) and convection-resolving climate simulations. This project relies on these two types of climate ensembles and the hydrological model WaSim to quantify changes in peak flows in the Rhône until the end of the century. 

Specifically, it has the following three objectives: 

1. to produce a climate data set for the Valais based on a SMILE and convection-resolving climate simulations; 
2. to estimate future peak discharges for the five FOEN monitoring stations along the Rhone, including their uncertainty; 
3. to analyse the processes that determine extreme floods in the future and how these differ from today's processes. These results provide information crucial for decision-making related to how to incorporate allowances for climate change in flood protection and adaptation in the Canton of Valais.