Tropical cyclone risk mapping for a coastal city using geospatial techniques

摘要

Tropical cyclone associated storm surges and their disastrous influences are becoming a major concern amongst the worldwide coastal community. The detailed risk modelling study seems an urgent need to support the storm surge mitigation actions. Using a Geographic Information System (GIS) based risk model, this study attempted to obtain both present and future storm surge wave heights in the Cox's Bazar Sadar Upazilla in Bangladesh. Linear storm surge model setup was done for the different return periods includes 5, 10, 20, 50, and 100 years. Also, to assess climate change effects, a 0.34 m sea-level rise in 2050 was tested using the regional scale surge models. The simulated storm surge model provided a time series dataset for the risk model and obtained risk maps comprised of the relationship among risk zone and the return periods. With the present inundation depth trend, the acquired risk maps of 50 and 100 year return period showed that 10.13% and 36.4% of the study area belongs to very high-risk zone respectively. Conversely, for future inundation depth conditions 30.83% and 49.9% of the study area would be within a very high-risk zone in 50 and 100 year return period respectively. This is envisaged that a detailed historical inundation dataset could enrich the adopted approach considering both present and future storm surge risk modelling for the Decision Support System (DSS). Also, this approach might be adopted for other identical coastal environments to aid mitigation programs and strategies.