Flood Modelling Using Integration of Multi-data Analysis and HEC-RAS Model in Mata Allo River, Sulawesi

¹ Department of Geography, Faculty of Mathematics and Natural Sciences, Makassar State University, 90244 Indonesia
² Informatics and Computer Engineering, Faculty of Engineering, Makassar State University, 90244 Indonesia
³ Master in Remote Sensing, Faculty of Geography, Gadjah Mada University, 55281, Indonesia

^* Corresponding author: ucasideng@unm.ac.id

Abstract

The amount of rainfall in a watershed with steep slopes, small cross-sectional areas, and less water catchment areas. This will cause an increase in water discharge in the river which can cause flooding. These characteristics can be found in Mata Allo River, Enrekang Regency. To identify the most flood-hit areas, the simulating model can be done utilizing the HEC-RAS program. Use of Satellite Imagery Data such as Sentinel-2 for extracting land use data information, and Sentinel-1 for data extraction of actual water bodies/rivers. The analysis is carried out by integrating the interpretation results from multi-sensor images with the results of modeling the flood inundation area using HEC-RAS. Based on the analysis results, the land use classification accuracy is 82.9% for Sentinel-2 data using the random forest algorithm. While for the actual extraction of water bodies using Sentinel-1 imagery was 89.6%. Approaching the threshold value between water and non-water bodies is taken using -13.39. The inundation area in the study area reached 87.66ha at the largest discharge model. The most affected land use after integrating each data is built-up land, most of which are settlements covering an area of 47.26ha.