Runoff hazard analysis of Wadi Qena Watershed, Egypt based on GIS and remote sensing approach

The geomorphological characteristics of the basin are more commonly used for flood hazard mapping of the watersheds suffering from scarcity of data. In this study, Geographic Information System (GIS) techniques have been used to carry out the morphometric analysis of Wadi Qena watershed. The morphometric parameters considered for analysis are Drainage intensity (Di), Form factor ratio (FFR) and Circularity ratio (Rc). Each parameter has been categorized into five grades ranking from 1 for the lowest hazard grade to 5 for the highest hazard grade. The analysis shows that with respect to the values of Di, FFR, and Rc, the highest three hazard degree areas covered about 24.2%, 56.9%, and 46.82% of the total area respectively. Consecutively, the number of sub-basins which are classified at the highest three hazard degrees equals 6, 32 and 38 sub-basins. The overall assessment map indicates that the sub-basins with hazard degree from moderate to high are equal 34 sub-basins with total area equals 9779.04 km2 (about 63.14% of the total area of Wadi Qena watershed). The final developed flood hazard map can initiate appropriate measures to mitigate the flood hazards in the area and helps for watershed management.