Abstract
Flash floods are one of the most common and destructive natural hazards, and recent flood events show their severe impact on Saudi Arabia. Flash floods are increasing year by year in duration and intensity, resulting in huge destructive impacts for the nation concerned. Anticipating the spatial patterns and occurrence of rainfall-induced floods is in high demand. Recent technique-based studies and their comprehensive results aid in understanding the flood potential of the drainage basins and in minimizing the risks of a threat to humans and of economic damage. Jeddah City is located at the western coast of the Red Sea in Saudi Arabia and is one of the most important coastal cities in the Arabian Kingdom. It has experienced several destructive flash flood events, particularly in 2009 and 2011, causing serious damage and significant loss of life. An analysis of the morphometric parameters using geospatial techniques provides significant insights into the hydrological response of the drainage basins to major heavy rainfall events. In this paper, two relative flood susceptibility scenarios were produced: drainage basin levels and very accurate pixel-level conditions. The morphometric comparison levels suggest that basins 1 and 7 are very high, whereas the other basins have moderate and low levels. The derived flood susceptibility map was integrated with the topographic position and wetness algorithms (TPI and TWI) through overlay processing. The integration analysis aids in realizing the relationship between the general basin morphometric characteristics and the in situ relief for producing the flood susceptibility spots over the entire basins. Thus, the method of this paper can be applied to evaluate the site-specific plan minimizing the effects of flash flood risks in similar areas.