Flood Risk Assessment in the Eastern Part of Dhaka City, Bangladesh : An application of hydro-dynamic model and other geo-informatics tools

Dhaka City is surrounded by a network of rivers which makes the city vulnerable to flooding. The present study provides an assessment of flood risk of eastern part of Dhaka City. In the risk assessment task, following flood frequency analysis, flood inundation map is produced using geo-informatics tools. Then secondary depth-duration-damage function of various land use classes is used to produce raster-based vulnerability map. Present monetary value of various land use classes is collected through survey. Then expected damage map is generated as a mathematical product of vulnerability, property value and area in GIS environment. Finally expected damage value is classified into several classes where each class represents risk of the study area. In comparison to the classical inundation maps, produced expected damage map generates more information about the flooding event because they bring into account the effects of flooding. These maps can be useful to evaluate policy alternatives and the results of this study may be used for future flood damage mitigation plan in the study area.