Recent Applications of Flash Flood Hazard Assessment Techniques: Case Studies from Egypt and Saudi Arabia

Flash floods are severe natural disasters due to their suddenness, frequency, and destruction. Every year, flash floods occur in Egypt and Saudi Arabia, which are located in the heart of the Middle East. Extensive areas in Egypt and Saudi Arabia are covered by mountainous topography. Intense rainfall can generate flash floods with their magnitude dependent on geomorphology and storm characteristics. Flash flood hazard assessment is a feasible way to mitigate potential damage and losses. Illumination, review, and comparison of assessment techniques of flash flood hazards represent an urgent necessity to evaluate advances and challenges in this discipline. Google-scholar and Scopus were used to collect 50 recent scientific papers, most of them published between 2011 and 2021, using the keywords: floods, hazards, assessment, Egypt, Saudi Arabia. Remote Sensing (RS) and Geographic Information systems (GIS) are the cornerstones of these studies, which include the Digital Elevation Model (DEM) and geoprocessing tools. The two items facilitate the calculation of morphometric parameters. Dividing the area and determining the hazard level were the main steps in flash flood hazard assessment. The considered studies relied on varied sets of morphometric parameters that ranged from 3 to 24 morphometric parameters. Area, ruggedness ratio, basin shape index, stream frequency, slope index, and drainage density are the common parameters in the assessment of flash flood hazards. In a flood zone, buildings made from brick have better sustainability in terms of both global warming mitigation and life cycle cost than other materials. Future studies are essential to illustrate the relationships between different morphometric parameters and flash flood hazard degree through field data and define a reliable unified set of morphometric parameters to assess the flash flood hazard degree.