Assessing the Impact of Anthropogenic Factors on Flash Floods in a Coastal City of Saudi Arabia

In recent years, coastal cities around the world have been facing an increase in flash floods, causing catastrophic effects on people, properties, and socioeconomic activities. However, the existing literature on this topic focuses disproportionately on the natural factors that trigger floods, such as hydrological, geotechnical, and environmental factors. To achieve a more comprehensive and effective understanding and management of floods, it is crucial to also consider the human factors that contribute to floods and their mitigation strategies. This study employs an expert-based Analytic Hierarchy Process (AHP) model to assess the human factors that contribute to flash floods in Jeddah, Saudi Arabia. The findings reveal that the highest-ranked factor contributing to flash floods was the inadequate open drainage systems (IODS) (29%), followed closely by the presence of impermeable surfaces (IS) (25%) and topography flattening (TF) (21%). Infrastructure failure (IF) and vegetation clearance (VC) were the least-rated factors, with priority weights of 17% and 7%, respectively. The study recommends stormwater management (SM) and the provision of open drains (POD) to mitigate flash flood risks in the study area and similar geographical regions resulting from anthropological factors contributing to flash floods. This study can help decision-makers to understand flash flood causes and design appropriate prevention measures.