Flood vulnerability analysis using the frequency ratio method with the watershed ecosystem in Bulukumba Regency, South Sulawesi Indonesia

Abstract

Bulukumba Regency is located in the Province of South Sulawesi. It is one of the main tourist destinations and phinisi boat industry that provides much economic added value for the community and local government. Apart from these advantages, the problem of flooding is an obstacle and has a detrimental impact on the regional economy. Drainage problems, weather anomalies, and land function experts in the upstream area are factors in the occurrence of floods in Bulukumba Regency. This study used remote sensing and geographic information systems (GIS) combined with the Frequency Ratio (F.R.) method to create flood vulnerability maps. The parameters in this study are based on literature studies, data availability, and research site conditions such as rainfall, earth curvature, river distance, marbles, altitude, topographic wetness index (TWI), stream power index (SPI), soil texture, soil permeability, geology, and land use/land cover (LULC). The results of the identification of flood events obtained a total area of flood events, namely 6,345 ha, which was identified with the highest F.R. value in the closure of pond land and coastal sand beds, sand soil texture, and lithology, namely alluvium rocks. Validation was obtained for the success rate with a value of 0.895 and the prediction rate with a value of 0.887. It shows the weight that falls into the good category. The area of insecurity has a high of 7.20% and high of 1.69%.