Digital elevation based flood hazard and vulnerability study at various return periods in Sirajganj Sadar Upazila, Bangladesh

The objectives of the study are flood hazard mapping and crops and settlement vulnerability assessment in a low laying riverine flood prone area of Bangladesh for different flood magnitudes. Flood hazard maps have been developed for different flood magnitudes integrating the Digital Elevation Model (DEM) data of Shuttle Radar Topographic Mission (SRTM) and interpolation of water level height of different water stations. Frequency analysis has been carried out to determine the water level of 2.33, 5, 10, 20, 50 and 100-year return periods flood. Landuse or land cover map has been generated from the LANDSAT satellite images supervised classification. Vulnerability functions of risk elements and flood hazard maps are analyzed in GIS environment to develop vulnerability maps. Most of the settlement vulnerable areas were found in low laying lands from the settlement and crops vulnerability maps. This flood hazard vulnerability map can be used for selecting the type of crops and area for cultivation during the monsoon period on the basis of magnitudes of inundation of different flood zones.