Flood Inundation Mapping of Buriganga River Floodplain using HEC-RAS 1D/2D Coupled Model

Abstract

Bangladesh, as a low-lying country, is prone to flooding. Flooding has adverse effects on many social and economic aspects. This research has been constructed based on developing flood inundation maps in one of the main rivers of Bangladesh named “Buriganga”. The main purpose of these inundation maps is to depict the degree of flood damage based on flood depth classification. The inundation maps are based on different administrative Upazila. ArcGIS (Aeronautical Reconnaissance Coverage Geographic Information System) has been used for developing flood inundation maps. Results were obtained from the simulation of 1D/2D coupled hydrodynamic model in HEC-RAS (Hydrologic Engineering Center River Analysis System). Results acquired from the simulation were maximum flood depth, maximum flood flow velocity, and maximum inundation area for different historical flood events and return periods. The findings of the analysis showed that among all historical flood events, the event of 1988 was disastrous in nature. In 1988, the most and least affected areas during maximum inundation were Kadamtali Thana and Serajdikhan Thana. This study will aid in providing an overview of the degree of flood damage that has already occurred. Thus, it will help in planning different mitigation measures and managing future aspects of socio-economic vulnerability.