Analysis of Flood Susceptibility Using Frequency Ratio Method in Paremang Watershed

Abstract

The flood in the Paremang Watershed caused damage to the road that connected several districts in South Sulawesi. In addition, it also inundated rice fields and residential areas, causing losses to residents. Therefore, this research was carried out to identify floods, find out the causes of floods that influence the occurrence of floods in the Paremang Watershed, and make a flood hazard map in the Paremang Watershed. This study uses SAR Sentinel-1 imagery to identify floods that occur in the Paremang watershed and frequency ratio analysis to look at the causative factors that influence flooding in the Paremang watershed and project a flood susceptibility map based on the causes of flooding. The results of this study show that in 2017–2021, an area of 3,446.12 ha was affected by flooding from the Paremang Watershed area of 92,717 ha. The land cover factor in the paddy field class with a frequency ratio value of 4.83, the slope factor in the 0-8% class with a frequency ratio value of 4.32, and the altitude factor in the 0-200 masl class with a frequency ratio value of 4.08 are the factors that most frequently occur in that factor. The flood hazard map in the Paremang watershed shows that the downstream part of the Paremang watershed is an area of high and very high susceptibility.