A geospatial approach for environmental risk susceptibility mapping of Khulna city in Bangladesh

Abstract

The entire coastal region of Bangladesh is highly susceptible to multiple disasters and hazards. With the increased pace of urbanization and change in climatic events, the hazard induced environmental risks are likely to increase in coastal cities and towns. Therefore, the identification of environmentally susceptible zones is very important for disaster risk reduction planning and building city resilience. This research aims to prepare the risk profile of coastal Khulna – a fast-growing metropolis and highly susceptible to multiple hazards. Three sets of Landsat images of 10 years intervals during 2000–2020 were analyzed against a dozen climatic, hydrological, geographical, and biophysical parameters/indicators derived from the literature survey. Eleven factors have been considered through the simple average method, where unequal weightage was assigned to the indicators depending on their relative role to make an area susceptible to risk. Hence, the environmental risk zones were identified after applying the Weighted Overlay Method. The finding shows that during the period the build-up areas increased by 27%, and the temperature by 2 °C. Additionally, an enormous increase in carbon outflows has made about 41% of additional areas susceptible to environmental risk during 2000–2020. The deterioration of environmental parameters and the risk profile is not uniform throughout the city, yet if the current trend of environmental degradation continues, it would seriously affect the resilience of Khulna city. The policy implication of this research is that the city authorities could take targeted intervention to lower specific risk and composite risk of a particular area based on informed choice.