Risk assessment of coastal erosion for Odisha coast along Bay of Bengal, India using coastal hazard wheel model

This paper makes an assessment of the coastal erosion hazard of the Odisha state with the use of ‘Coastal Hazard Wheel’ methodology which is a multi-hazard assessment as well as a management tool in a changing global climate. This study analyses the coastal environment to assess the vulnerability profile of coastal erosion by using bio-geophysical parameters such as geological layout, tidal range, exposure to waves, balance or deficit of sediments, characteristics of flora and fauna and exposure to storm climate. These are also used in analysing climate change hazards of the coast which are inherent to an area like saline flooding, gradual inundation, ecosystem disruption and salt water intrusion. CHW framework has generated information about the degree to which coastal erosion is inherent in a particular coastal location along the coast. This application has used remote sensing data from the public domain and a GIS approach to screen the problem with an appropriate scale as suitable for regional and national planning purposes with a management perspective because of limited data availability. The study has generated coastal erosion data and maps for the 480 km of the coastline dividing the coast in to 14 different morphological segments. Assessment of this hazard shows that 50 percent of Odisha's coastline is vulnerable to a high or very high inherent hazard of erosion, 45 percent exhibits a lower level of erosion presence and 5 percent is moderately vulnerable to erosion. This study has revealed increasing magnitude of coastal erosion than previous assessments by different researchers which were mostly based on coastal vulnerability indices. The study also identifies a number of possible erosion hazard management and mitigation options which can be used depending on their location specific field data and coastal characteristics. The finding of the study is significant in view of its contribution towards a first step in understanding coastal erosion at the regional level for their management. However, input of local data and manmade structures along the coast in the model would enhance the results for the site-specific mitigation measures.