Spatial risk assessment of tropical cyclone for disaster mitigation in a coastal district of India using geospatial technology

Abstract

Frequent cyclones in the Bay of Bengal (BoB) cause substantial loss to property and human lives. This asserts for the systematic vulnerability assessment to mitigate their adverse impact. Odisha is one of the most vulnerable states in India exposed to the tropical cyclones. Most of the studies related to tropical cyclone risk mapping and identification of evacuation route in Odisha are limited at scale greater than district level. This study investigated risk of the tropical cyclone Yaas in the Balasore district of Odisha (India) at block level using Fuzzy Analytical Hierarchical Process (FAHP) and Geographic Information System (GIS) based spatial analysis methods. A total number of 15 parameters classified under physical (6), social (6) and mitigation (3) were used for this purpose. The weight of these parameters was determined using FAHP. However, categorization of weights into the high, medium and low was performed using a Weighted Overlay Analysis (WOA). Further, a spatial vulnerability risk map was generated by dividing the multiplication of physical and social vulnerability indices with that of the mitigation capacity. Analysis of results show that about 44.6 % and 49.3 % of study area are covered under the category of the ‘high’ and ‘moderate’ risks, respectively, while ∼6 % under the ‘low’ risk category. The high-risk zones are predominantly situated in the western, south-western, central and eastern regions of the study area. These are not only close to the cyclone track and coastlines but also have revealed poor mitigation capacity. Additionally, network analysis was used to determine the evacuation routes (shortest route path) from the outlets/settlements to the cyclone shelters based on the developed risk map. These spatial data (e.g., vulnerability risk map and evacuation routes) can be used by district's emergency administration and management authorities to develop efficient cyclone mitigation plans in the Balasore district. Thus, the study has demonstrated methodological robustness through the integration of FAHP and geospatial techniques in spatial risk assessment for the tropical cyclone at district level.