Kajian Risiko Banjir Kawasan Kota Medan Bagian Selatan Berbasis Sistem Informasi Geografis

Abstract

The Southern Medan City area, which includes six sub-districts, is one of the areas in Medan City that frequently experiences flooding. The cause of flooding is often caused by the overflowing of the Deli River and the high intensity of rainfall. In order to reduce the impact caused by flooding, flood risk mapping is required to map areas at risk of flooding. The level of flood risk influenced by the results of the analysis of the level of flood hazard and vulnerability. The flood hazard level parameter is in the form of return period rainfall values. Furthermore, flood vulnerability parameters are divided into two aspects, namely aspects of social vulnerability and physical vulnerability. In determining the level of social vulnerability, vulnerability is influenced by the population density of the Kelurahan, while in determining the level of physical vulnerability, the level of vulnerability is influenced by four parameters including land use type, slope, drainage density, and landform. This research is a quantitative study using scoring, overlay and Geographic Information System (GIS) methods. Based on the results of GIS analysis, it is found that on the 10-year return period flood risk map, the high flood risk level covers an area of 2,153 km2 or equal to (2,51%), the medium flood risk level is 83,341 km2 or (97,48%). On the 25-year return period flood risk map, the high flood risk level covers an area of 8,99 km2 or equal to (10,51%) and the medium flood risk level covers an area of 76,499 km2 or equal to (89,48%). On the 50-year return period flood risk map, the high risk level covers 71,588 km2 or equivalent to (84,02%) and the medium risk level covers 13,613 km2 or equivalent to (15,97%). With the information on the level flood risk obtained, it can be a basic guideline for stakeholders to make decisions in flood disaster mitigation efforts.