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

Abstract

The West Medan City area, which includes three sub-districts, is one of the areas in Medan City that often floods. The cause of flooding is often due to the high intensity of rainfall. In reducing the impact of floods, flood risk mapping is needed to map areas that are at risk of flooding. The level of flood risk is influenced by the results of the analysis of the level of danger and vulnerability of floods. The flood danger level parameter is in the form of a re-period rainfall value. Furthermore, flood vulnerability parameters are divided into two aspects, namely social vulnerability and physical vulnerability. In determining the level of social vulnerability, vulnerability is influenced by the population density of the village, while in determining the level of physical vulnerability, the level of vulnerability is influenced by four parameters, including the type of land use, slope, drainage density, and land form. This research is a quantitative research using the scoring method, overlay and Geographic Information System (GIS). Based on the results of GIS analysis, information was obtained that on the flood risk map for the 10-year recurrence period, the high flood risk level was 2,153 km2 or (2.51%), the medium flood risk level was 83,341 km2 or (97.48%). In the 25-year re-period flood risk map, the high flood risk level is 8.99 km2 or equivalent (10.51%) and the moderate flood risk level is 76.499 km2 or equivalent to (89.48%). On the 50-year recurrence flood risk map, the high risk level is 71,588 km2 or equivalent (84.02%) and the medium risk level is 13,613 km2 or equivalent (15.97%). The information on the level of flood risk obtained can be a basic guideline for stakeholders to make decisions in flood disaster mitigation efforts.