International audienceIn semi-arid regions such as the Mediterranean basin, floods usually represent a largecontribution to water resources. In addition, climate scenarios indicate a possible increase in extremeevents in the Mediterranean region. Therefore, it is necessary to model floods to better understand theprocesses involved and predict these risks. The Moroccan catchments flowing downstream of theHigh-Atlas Mountains are among the areas most vulnerable to flooding. The Issyl catchment (170km²)is located at the foothills of the High Atlas Mountains, with altitudes ranging from 632 to 2295m, andproducing floods that directly affect the city of Marrakech. The Rheraya catchment is a mountainousbasin with altitudes ranging from 1000m to 4165m, and affected by violent floods that constitute athreat for the villages located in low elevation areas. This paper compares the efficiency of two modelstructures, based either on the Soil Conservation Service - Curve Number (SCS-CN) method or theGreen and Ampt model. In addition, the comparison is also performed using global and semidistributed model structures to account for the spatial variability of rainfall. A total of 21 flood eventsthat occurred between 2008 and 2014 were tested for the two watersheds. The results of the globalapproach show a good reproduction of the maximum discharge with both models, but the flood volumeare not adequately reproduced for the Rheraya catchment. The results of the semi-distributedapproach show a clear improvement for several events, with better Nash criterion values on averagewith the SCS-CN model. In conclusion, we found that the Green and Ampt model outperforms theSCS-CN model in global mode, and it is the opposite in semi-distributed mode. Since the parametersof the Green-Ampt model can be successfully approximated using soil information, this model appearsadequate for climate changes studies or real time flood forecasting
