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Publication Date

2017

Keywords

DEM, Satellite image, Inundation simulation, Flood risk map

Abstract

Recent advances in Geographic Information Systems (GIS) and hydrological modeling techniques allow their powerful integration. Since flood modeling has greatly improved it is believed that these advances will provide for a more efficient and a more accurate alternative to traditional methods for studying watersheds. In this paper, assessment of flood risk by developing a Flood risk map for eastern Dhaka was carried out by hydrodynamic simulation with the integration of satellite image (DigitalGlobe image; Date of imagery: 7th March 2007), DEM data from SRTM and the hydrologic field observed data. As the topography of the area has been considerably changed due to rapid land-filling by land developers which was observed in recent satellite image, the acquired DEM data was modified to represent the current topography. The inundation simulation was conducted using hydrodynamic program HEC-RAS for flood of 100-year return period and a flood inundation map was prepared according to the simulation result using the software ArcGIS. Finally, to assess the flood risk of that area, a Risk map was prepared where risk was defined as the product of hazard (i.e. depth of inundation) and vulnerability (i.e. the exposure of people or assets to flood). This map should be helpful in raising awareness of inhabitants, in assigning priority for land development and for emergency preparedness including aid and relief operations in high risk areas in the future.

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