Flooding in the Air Bengkulu Watershed is related to the physical characteristics of the area, particularly the topographic differences between the upstream and downstream regions. Downstream areas with low elevation and gentle slopes tend to have higher potential for surface runoff accumulation. This study aims to map topography-based flood susceptibility using the Geographic Information System and Analytical Hierarchy Process (GIS-AHP) as preliminary information for identifying flood-prone areas in the Air Bengkulu Watershed. The parameters used were elevation and slope, derived from the National Digital Elevation Model (DEMNAS), then reclassified into five susceptibility classes and weighted using AHP. The weighting results showed that elevation had a weight of 0.667, while slope had a weight of 0.333. The integration of both parameters through weighted overlay produced a topography-based flood susceptibility map, with the very high class covering 121.21 km² or 24.27% and the high class covering 104.49 km² or 20.92% of the classified area. Combined, both classes covered 225.70 km² or 45.19% of the classified area, mainly distributed in the downstream to middle parts of the watershed. Spatial validation using verified flood occurrence data showed spatial agreement between documented flood locations and areas identified as flood-prone based on the mapping results. Therefore, this study provides preliminary spatial information to support the identification of priority areas for flood mitigation, particularly in the downstream part of the Air Bengkulu Watershed. However, the resulting map represents an initial topography-based susceptibility assessment, not a complete representation of all flood-causing factors.
Copyrights © 2026