GIS-Based Flood Hazard Mapping and Spatial Analysis in North Luwu Regency, Indonesia

Floods are among the most frequent and destructive natural disasters in Indonesia, severely affecting human settlements, infrastructure, and regional development. North Luwu Regency, particularly Masamba, experienced a catastrophic flash flood in 2020 that caused loss of life, significant infrastructure damage, and long-term disruption to community livelihoods, emphasizing the urgent need for resilient and sustainable flood mitigation strategies aligned with the Sustainable Development Goals (SDGs), especially SDG 11 and SDG 13. Previous mitigation efforts relying primarily on structural infrastructure have proven insufficient due to sedimentation, inadequate maintenance, and rapid land-use change. Therefore, a holistic and evidence-based approach is required to address hydrological, ecological, and socio-spatial interactions in flood-prone regions. This study applies GIS-based spatial analysis using four primary datasets: Digital Elevation Model (DEM), flow direction, flow accumulation, and flood hazard maps. The integration of these datasets provides a systematic framework for developing spatially informed flood mitigation strategies in North Luwu Regency. Spatial overlay and hydrological modelling identified high-risk downstream zones, critical upstream catchments, and demonstrated strong relationships between topography, flow concentration, and hazard distribution. Findings reveal that low-lying downstream areas near the coast and river confluences are most susceptible to flooding, overlapping significantly with densely populated settlements and agricultural zones. The study recommends a dual mitigation strategy integrating structural measures (retention basins, drainage enhancement, and sediment control) with non-structural actions (ecosystem restoration, community-based early warning systems, and land-use regulation) within an Integrated Flood Management (IFM) framework. This integrated approach is essential for enhancing regional resilience, supporting sustainable spatial planning, and strengthening disaster risk reduction policies in accordance with the SDGs.