Tropical Cyclone Vulnerability Mapping Using Geospatial Techniques: Application to a Coastal Upazila in Bangladesh

Abstract:

Cyclones are one of the most catastrophic natural disasters. Globally, many coastal regions are vulnerable to different categories cyclones. In Bangladesh, disasters from tropical cyclones are annual occurrences in coastal areas. The intensity and extent of damage due to tropical cyclones are very high. An appropriate mapping approach is essential for producing detail vulnerability assessments to deliver useful information for reducing the impacts of cyclones on people, property and environment. The present study developed and tested a vulnerability mapping approach for tropical cyclone impacts in Sarankhola upazila a 151 km² local government area located in coastal Bangladesh. The study applied the approach by integrating remote sensing, field data and multi-criteria evaluation at regional scales covering <1000 km². Seven criteria concerned with cyclone impacts were considered for the study: elevation, slope, geomorphology, proximity to coastline, proximity to cyclone track, land uses and population density. Thematic raster map layers were prepared for every criterion and weighted using Analytical Hierarchy Process (AHP) with sensitivity analysis. Weighted Linear Combination (WLC) technique was used for overlaying standardized criteria maps with their weights to produce the vulnerability map. Our results indicated that 15% of the study area had very high vulnerability; mostly close to the river and densely populated areas, with 40 % area as high vulnerability on cropped grounds. Around 25% area was classified at moderate vulnerability covering most of the forests. The low and very low vulnerable area accounts the 12% and 8% respectively. This approach provided very promising result and it was verified by field survey. The result provides the strong applicability of this approach to assess the vulnerability of coastal Bangladesh to tropical cyclones.