Assessing and Mapping the Flood Susceptibility of the Krueng Aceh River Basin in Indrapuri District, Aceh Besar Regency, Aceh Province, Indonesia Using GIS-Based Hierarchical Criteria Analysis

Abstract

Extreme weather, such as the Senyar cyclone in November 2025, generated river flooding in the Krueng Aceh River Basin. River flooding is a major natural hazard in river basin areas, particularly where low-lying topography, fluvial geomorphology, and intensive land use increase flood susceptibility. Indrapuri District, Aceh Besar Regency, is susceptible to flooding from the Krueng Aceh River due to its location within the downstream transition zone of the Krueng Aceh River Basin, which is predominantly characterized by fluvial landforms. This study aims to evaluate and spatially delineate flood susceptibility in the Krueng Aceh River Basin through an integrated Analytical Hierarchy Process (AHP) and Geographic Information System (GIS) approach. Nine physical-environmental parameters were incorporated into the analysis, comprising rainfall, elevation, slope, curvature, Topographic Wetness Index (TWI), distance from river channels, drainage density, land use, and landform. The AHP-based weighting revealed that proximity to river channels exerted the greatest influence on flood susceptibility, followed by landform and elevation. The resulting susceptibility index indicates that part of the area is classified as highly susceptible (303.38 ha), moderately susceptible (412.03 ha), and low susceptibility (1,282.87 ha) to flooding. The highly susceptible areas are concentrated primarily in low-elevation zones adjacent to river channels, where elevated TWI values and the floodplain create favorable conditions for water accumulation and prolonged inundation. Conversely, areas with low susceptibility are generally situated at higher elevations and exhibit comparatively favorable drainage conditions, reducing the likelihood of surface-water accumulation. Overall, the findings demonstrate that the integrated AHP-GIS framework can effectively capture the spatial variability of flood susceptibility within the Krueng Aceh River Basin. The resulting map provides a spatially explicit basis for flood mitigation planning, risk-informed land-use management, and the prioritization of vulnerable areas by local authorities. Furthermore, the assessment can support community-based disaster preparedness and contribute to sustainable regional development by promoting land-use decisions that are better adapted to existing geomorphological and hydrological conditions.