Kajian Risiko Banjir Kawasan Kota Medan Bagian Timur dalam Bentuk Peta Risiko Banjir Berbasis Sistem Informasi Geografis

Abstract

According to the Technical Implementation Unit of the Medan City Bina Marga Bina Konstruksi Water Resources Office, the Eastern Medan City Area, which includes three sub-districts, is one of the areas in Medan City that often experiences flooding. The cause of flooding is often caused by the overflow of the Deli River and the high intensity of rainfall. The occurrence of flooding causes a decrease in the quality of the urban environment. Flooding in Medan City is often caused by natural factors such as flooding due to upstream submissions, rainfall intensity, limited capacity of drainage and rivers, sedimentation erosion and non-natural factors such as poor condition and management of drainage channels. In reducing the impact caused by flooding, flood risk mapping is needed to map areas at risk. The level of flood risk is influenced by the results of the analysis of the level of flood hazard and vulnerability. Flood hazard level parameters are in the form of return period rainfall values. Furthermore, flood vulnerability parameters are divided into two aspects, namely physical and social vulnerability aspects. 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. In determining the level of social vulnerability, it is influenced by the population density of the Village. This research is a quantitative research with scoring, overlay and Geographic Information System (GIS) methods. Based on the GIS results, information obtained on the 10-year return period flood risk map, the high flood risk level is 15.896 km2or (80.95%), the medium flood risk level is 3.74 km2 or (19.05%). On the 25-year return period flood risk map, the high flood risk level covers an area of 15.99 km2 or equal to (81.43%) and the medium flood risk level covers an area of 3.646 km2 or equal to (18.54%). On the 50-year return period flood risk map, the high risk level covers 16.457 km2 or equivalent to (83.8%) and the medium risk level covers 3.179 km2 or equivalent to (16.2%). With the information on the level of flood risk obtained, it can be a guideline for making decisions in flood disaster mitigation efforts