A coupling of hydrologic and hydraulic models appropriate for the fast floods of the Gardon river basin (France): results and comparisons with others modelling options

Abstract

Mediterranean catchments are regularly affected by fast and flash floods. Numerous hydrologic models were developed, and allow to reconstruct these floods. However, these approaches often concern average size basins, of some hundreds km2. At more important scales (>1000 km2), a coupling of hydrologic and hydraulic models appears to be an adapted solution. This study analyses the performances of a coupling of models and compares them with those of others modelling strategies. The distributed SCS-LR hydrologic model implemented in the ATHYS modelling platform ( http://www.athys-soft.org ), and the MASCARET hydraulic modelling code, based on full Saint-Venant equations, are employed. The coupling is applied to the Gardon river basin (2040 km2), in the southeast of France. The results are satisfactory at the downstream stations. Furthermore, the coupling has few parameters, expecting interesting perspectives for flood forecasting.