FLASH FLOOD SUSCEPTIBILITY ANALYSIS IN JEDDAH, SAUDI ARABIA, USING A GIS-BASED AHP APPROACH

Floods are among the most devastating natural hazards, threatening human society worldwide, even in arid regions like Saudi Arabia. As the severity and frequency of floods increase, there is a growing need for improved flood risk awareness to minimize damage to life and property. Given the complexity of flood evaluation and prediction, a criteria-based approach that organizes key flood parameters offers an effective solution, such as the Analytical Hierarchy Process (AHP). This study integrates AHP with GIS to model flash flood risk in Jeddah, Saudi Arabia. Key parameters include precipitation, elevation, slope, distance to drainage networks, land cover, and geology. A pairwise comparison was conducted to rank these criteria by their contribution to flood risk. Four risk scales were developed to represent the likelihood of flood hazards (ranging from low to very high). The results show that the eastern and central parts of Jeddah, particularly areas leading to the coast, are the most vulnerable due to their proximity to natural water channels and low-lying, intermittent topography that forms valleys. In contrast, the western and northern zones, which feature higher elevations and fewer paved surfaces, exhibit low to moderate flood susceptibility. Urbanization in Jeddah further exacerbates flash flooding during seasonal downpours. Our findings suggest that authorities should implement mitigation strategies, such as widening the drainage systems and reducing the paved surfaces in high-susceptible areas, to better control future flood events.