Analisis Area Genangan Banjir di Sungai Babura Menggunakan Geomorphic Flood Index Modifikasi

Abstract

Flood disaster is one of the natural disasters that often occurs in Indonesia and the capital city of North Sumatra Province, Medan City, is no exception. For flood disaster mitigation that aims to minimize losses due to the impact of flooding, it is necessary to map vulnerable areas of natural disasters, especially flood inundation. This research aims to produce a flood inundation map of the Babura river that crosses the Medan city area due to the overflow of the Babura river using the Geomorphic Flood Index (GFI) method and the modified Geomorphic Flood Index (GFI) method from QGIS software. The input data of this tool is the processed data of Digital Elevation Model (DEM) data such as DEM Fill, Flow Direction, and Flow Accumulation for the final result of flood inundation map. In conducting this research, data collection was carried out which included rainfall data from BMKG, Digital Elevation Model (DEM) data, Babura Watershed digital map and land use data. From the modeling results, flood inundation occurs in various types of land cover with plantations as the largest area affected with an area of 236.79 ha. Inundation also occurs in residential areas and places of socio-economic activities with an inundation area of 76.06 ha. The analysis also showed that Medan Polonia and Medan Johor sub-districts experienced flooding with the largest impact of 25.67 ha and 18.19 ha, respectively. In addition, Pancur Batu Sub-district, New Medan Sub-district, Medan Tuntungan Sub-district, and Medan Maimun Sub-district were also affected by floods with an area of 3 ha to 10 ha, followed by Medan Selayang Sub-district, and Namorambe Sub-district with flood areas of less than 1 ha.