Résumé
Floods have significant socio-economic impacts, particularly in the Mediterranean regions, and there is strong questioning about a possible increase in their intensity due to climate change. In the Mediterranean, it is now established that extreme precipitation could increase in future climate scenarios, following the trend already started in the observed data. Nevertheless, the trends observed in the South of France indicate a decrease in the frequency of floods in the majority of the basins, despite the increase in intense precipitation causing these episodes, due to the decrease in soil moisture which can strongly modulate the hydrological response of the basins. Conversely, a trend towards an increase in the intensity of the most extreme floods is observed in some basins. It is indeed imperative to differentiate the behavior of different types of basins, urban, natural or agricultural, at different scales, in the face of changes in the regime of extreme rainfall. Although a lot of work has been done to estimate future climatic conditions, we are not well aware of the possible modifications of hydrological variables and surface conditions, with complex interactions between precipitation and infiltration processes on hillslopes, which can strongly modulate the magnitude of floods. It is therefore necessary to better understand and quantify the hydrological response in a context of climatic and anthropogenic changes.