Spatial vulnerability assessment of floods in the coastal regions of Bangladesh

Vulnerability assessment is considered as a key step towards effective disaster risk reduction. It is multi-dimensional, and its assessment is complicated due to the social, economic, political, and institutional patterns of societies. The demand for comprehensive vulnerability assessments including a spatial differentiation of vulnerability is high. In this study, a methodology for the spatial vulnerability assessment of floods in the coastal regions of Bangladesh is developed. For a 706 km2 area in the Sundarbans Reserve Forest and its surroundings 12 vulnerability domains are defined and 44 indicators are developed. These indicators are ranked by 20 local experts through an analytic hierarchy process (AHP). All data-sets are transformed into 100 m resolution raster (grid) data-sets in a geographic information system (GIS). This grid approach surmounts the problems of data availability and different data scales, and allows the inclusion of indicators for the social dimension. A spatial vulnerability assessment is carried out using GIS weighted overlay. The resulting maps and figures reveal both the extents and levels of vulnerabilities. The assessment maps are validated by local experts visually, and by using maps of past floods. Ultimately, the transferability of this approach to other contexts is discussed.