GIS application on Flood Vulnerability Mapping Based on Land Use Change in Manado City

Manado City, situated on the shore of the Sulawesi Sea, serves as the hub of activity, and the capital of North Sulawesi Province frequently encounters flooding. One of the hypotheses regarding the frequent floods is attributed to the decrease in vegetated areas. The research aims to use GIS to map flood vulnerability related to land use change in Manado City (Tuminting, Wanea, and Wenang Districts). The approach employed is the map overlay analysis method, utilizing scoring to ascertain the water absorption capacity and identify locations vulnerable to flooding. Land use at the research location showed substantial changes between 2013 and 2023, with vegetated land conditions declining by 77.25 hectares (4.49%) while settlements expanded by 226.83 hectares (13.18%). The water absorption area at the research site is categorized as low and very low, measuring 66%, while the absorption capacity for moderate, high, and very high is 34%. Overlay of maps of land use, slope, soil type, river density, and rainfall used to determine five flood vulnerability levels. The results show areas classified as very vulnerable: $\mathbf{5 7 5. 5 2}$ hectares (33%), vulnerable: $\mathbf{5 1 5. 6 9}$ hectares (30%), slightly vulnerable: 361.02 hectares (21%), slightly safe: 177.79 hectares (10%), and safe: 94.44 hectares (5%). GIS successfully solves problems in urban and regional planning by mapping disaster-prone areas, i.e., flood vulnerability areas based on land use changes.