Flood forecast and flood vulnerability modeling in case of Wadi Fez, Morocco

The Wadi Fez basin, part of the Great Sebou Basin in northern Morocco, is located in the North part of the Tabular Middle Atlas and the central part of the Saïs plain. Its physiographic and morphological study contributes to a better knowledge of its functioning. It allows proposing solutions to the decision makers for better socio-economic management of the region. We conduct our research based on the hydrological regime, the analysis of extreme flows frequency, the volume of precipitation, the concentration time, and the return periods of floods. Our results have determined that the Wadi Fez basin is rainy and sometimes torrential in winter, often generating floods in Fez and its surroundings. Moreover, the parameters of the substrate induce a large volume of water resources from upstream. However, the weak structure of the Wadi Fez hydrographic network and the water balance has highlighted a considerable loss of water resources, which handicaps the irrigation system of the vegetables and plantations of the basin. Furthermore, the hydrological modeling of the Wadi Fez basin by the HEC-HMS platform and the use of the HEC-RAS software have allowed the definition of the flood vulnerable areas and thus a better understanding of the one and two-dimensional modeling peak flow. Finally, the annual modulus and the different coefficients show hydroclimatic fluctuations of semi-arid climatic conditions, with a temperate winter and a hot summer. Therefore, our results suggest that it is necessary to decrease the infiltration/flooding ratio. For this reason, we recommend monitoring water runoff, protecting surface soils from flooding and active erosion by planting trees, and installing dikes and small dams to recharge groundwater in this basin.