Vulnerability assessment of flash floods in Wadi Dahab Basin, Egypt

Floods are considered one of the most severe natural disasters worldwide. They impact vast areas, particularly in arid/semi-arid regions, causing serious damages with thousands of human casualties and billions of Euros in economic losses. This study contributes to a comprehensive evaluation of flash flooding occurrences, impacts, and possible mitigation. In this study, The Dahab region in southern Egypt’s Sinai Peninsula was selected for flash flooding vulnerability assessment. Although located in an arid region, it suffers from frequent and severe flash floods. Here, a straightforward workflow was applied to simulate the impact of flash flooding and assess the vulnerability of the Dahab area via consideration of a maximum storm event as a worst- case scenario. Originally, morphometric analysis was performed to determine the most hazardous sub-basins susceptible to flash flooding. The highest recorded storm event in the region was selected to calculate the maximum volume of surface runoff for the model simulation. Then, the hydrologic model and River Analysis System (HEC-RAS) software were used to calculate the inundation level across the entire city of Dahab. Despite some data limitations, this study shows clearly that the Dahab area would have problems incurring from flash flooding if no mitigation measures were to be considered. Results indicate that the area of Dahab is greatly vulnerable to flash flooding with approximately 72% of the total infrastructure being negatively impacted in the worst-case scenario. The adopted approach used in this study can be applied efficiently in similar regions in the Sinai Peninsula or elsewhere.