Index-Based Spatial Assessment of Flood Hazard and Multi-Sectoral Vulnerability in Flood-Prone Areas

Floods are among the most frequent and damaging natural hazards in Indonesia, particularly in flood-prone subdistricts. This study conducts an index-based spatial assessment of flood hazard and multi-sectoral vulnerability in Momunu Subdistrict, Buol Regency, Central Sulawesi. Using Geographic Information Systems (GIS), flood hazard mapping reveals that the total flood-prone area covers 3,022.02 hectares, consisting of low (1,674.18 ha), medium (958.05 ha), and high (389.79 ha) hazard classes. The most affected villages include Panimbul (low hazard), Pinamula (medium), and Lamadong I (high hazard), especially in areas with flat topography near river systems. The vulnerability analysis incorporates social, physical, economic, and environmental indicators. Social vulnerability is highest in villages such as Potugu, Pomayagon, and Guamonial. Physical vulnerability is generally low to moderate but increases near rivers and in settlements with non-permanent structures. Economic vulnerability shows significant variation, with the highest index value of 0.565568, indicating substantial exposure to potential economic losses. Environmental vulnerability peaks at an index value of 0.633431, reflecting ecological stress due to land-use changes and diminished protected areas. Furthermore, the exposed population in Momunu Subdistrict is estimated at 8,637 people, including 39 persons with disabilities, 4,461 males, and 4,176 females. Estimated flood-related losses reach IDR 49.063 billion, comprising IDR 49.025 billion in physical damage, IDR 38.32 billion in economic losses, and environmental degradation over 869 hectares. These findings underscore the urgent need for targeted flood mitigation strategies and resilience planning based on spatially explicit risk assessments.