GEOSPATIAL ASSESSMENT OF FLASH FLOOD SUSCEPTIBILITY IN MAKKAH, SAUDI ARABIA

Flash floods pose a significant hazard in regions like Makkah, Saudi Arabia, due to rapid urbanization, complex terrain, and limited drainage infrastructure. This study aims to map and assess flash flood susceptibility using a geospatial approach integrated with the Analytical Hierarchy Process (AHP), focusing on key factors such as elevation, slope, rainfall, geology, proximity to drainage networks, and land use/land cover. AHP is used to assign relative weights to these factors based on their influence on flash flood occurrence. These weights are then integrated into a Geographic Information System (GIS) to produce a susceptibility map, categorizing the region into low, moderate, and high susceptibility zones. The results show that the western part of Makkah is most at risk of flash flooding, driven by steep slopes, higher elevations, and limited infiltration capacity due to local geology and urbanization. Elevations ranging from 101 to 960 meters significantly influence water flow, with lower elevations acting as flow channels and higher elevations accelerating runoff. Urban areas with impervious surfaces near drainage networks are also critical areas of concern. These findings highlight the importance of geomorphological and urbanization factors in flood risk. The susceptibility map offers valuable information for urban planners and policymakers, emphasizing the need for targeted interventions such as improved drainage systems, slope stabilization, and revised land use planning to mitigate flash flood risk. These measures are essential for addressing flood challenges while supporting sustainable urban growth. This research contributes to enhancing flood risk management in Makkah and provides a practical model for assessing flood risk in other arid regions. By addressing both environmental and anthropogenic factors, the study supports sustainable development and informs strategies to reduce flash flood impacts.