Application of remote sensing and GIS for assessing and proposing mitigation measures in flood-affected urban areas, Egypt

This study investigates the impact of the October 2016 flash floods in urban areas located in selected catchments along the Nile Valley and Red Sea regions for the assessment and the proposal of feasible mitigation measures. Optical and radar satellite images acquired before and shortly after flash flood events were analyzed to detect and map the active contributing channels, the interfering urban areas, the response of natural depressions and storage areas, and the conveying channels to the flash floods. The quantitative estimates of October 2016 flash floods parameters including total rainfall depths, the active channel cross-sectional areas, and the spatial extent of storage areas of the accumulated flood water were measured. Various hydrological parameters were extracted using the Digital Elevation Model (DEM) for the estimation of water volumes of largely inundated depressions. It was determined that the October 2016 flash floods were devastating in the Ras Gharib area; however, these floods were properly managed at both the New El Minya and New Qena urban areas. In contrast, the flash floods at the Al-Saaf and Atfih urban area require urgent mitigation measures given that wastewater depressions and sanitary facilities are prevalent in the downstream reaches of the studied drainage basins.