A combined approach for flood hazard assessment using hydrological, hydraulic and GIS modeling case study of El Hamiz Wadi, Algeria

Flood hazard is one of the most destructive natural phenomena causing a significant material damage and human losses in Algeria during the past decade. The aim of this study is to assess and characterize the flood hazard in El Hamiz watershed (Algeria). In addition, this study identifies areas and elements prone to this hazard to minimize the damages and losses. The methodology used in the present study is based on a combination of hydrological and hydraulic modeling using the Hec-Ras software and mapping techniques using a Geographic Information System (GIS). The flood hazard assessment model of El Hamiz wadi using different hydrological (rainfall / runoff transfer and return period), hydraulic (water level and flow velocity) and exposure (land use data and socio-economic data) parameters revealed that the downstream part of the studied area is the most susceptible to flood events. The mapping of flood-prone areas indicated the extent of this phenomena on the El Hamiz wadi banks, especially through heavy submersion of residential areas characterized by a high urban concentration including inhabitants, activities and infrastructures.