Vulnerability and risk assessment

Abstract

Using census and spatial databases, this chapter demonstrates the assessment of flood vulnerability and risk zoning in the megacity of Dhaka. A place-based approach was adopted to evaluate flood vulnerability at the community level. A method comprising the AHP and the WLC was used to operationalize the conceptual model within a GIS framework. A number of biophysical variables were used to derive the physical vulnerability index (PVI). In addition, nine variables were extracted from diverse sources to derive the social vulnerability index (SVI). To determine the coping capacity of a community, five variables were employed and a coping capacity index (CCI) was developed. Using the PVI, SVI, and CCI, a composite vulnerability index (CVI) was prepared, which revealed that 28 and 14% of the population in the study area were located between high and very high vulnerable zones, respectively. Thirty-six percent were in katcha housing units, which are largely home to marginal people and were in the very high vulnerable zone, revealing the susceptibility of human settlements to floods. Flood hazard data were multiplied with the CVI to delineate the flood risk zone. A total of 18.5% of people lived in high and very high flood risk zones, which was further compounded by the number of females, young, elderly, and illiterate persons. At least 25.8% of housing units were located in these zones. The flood risk map developed in this study could be used as baseline information for the development of pertinent mitigation measures to ameliorate flood loss in the days ahead.