Vulnerability Assessment of the Inherent Hazards of Climate Change on the Coastal Environment of the Mahanadi Delta, East Coast of India

Abstract

This study makes a vulnerability assessment of the coastal hazards of the Mahanadi delta across Bay of Bengal using coastal hazard wheel model which is a multi-hazard assessment and management tool in a changing global climate. This paper analyses the coastal environment of the Mahanadi delta to evaluate the vulnerability profile by assessing its inherent hazards such as ecosystem disruption, gradual coastal inundation, intrusion of salt water into the freshwater aquifers, coastal flooding and beach erosion. The study uses the bio-geophysical parameters such as geomorphological layout, nature of wave exposure, range of tidal amplitude, coastal vegetation, balance and deficit of coastal sediments and presence or absence of storm climate which are also used in assessing hazards of climate change which are inherent to a coastal zone. The model has used remote sensing data from the open sources and a GIS framework to assess the problem from the management perspective. The study has generated data and maps about the degree to which a particular location along the coast is vulnerable to the hazards inherent to the coast dividing the coastline into several morphological segments. The study reveals that the deltaic and pro-grading shoreline of the Mahanadi delta has undergone erosion and accretion in a phased manner with erosion exceeding the rate of accretion. The rate of erosion has varied from 4 m to 15 m per year at different sites along the delta front. The study has generated vulnerability data and maps for the different coastal hazards inherent to the coast, i.e. saltwater intrusion, saline inundation, coastal erosion, flooding, ecosystem disruption and associated risk levels at the regional level for the 279 km of coastline of the delta. The study reveals that 28.6% of Mahanadi delta’s coastline has a very high risk, 47.6% has high risk, 16.99% has moderate risk and 6.81% has a lower risk in respect of different inherent hazards. The study reveals an increasing magnitude of vulnerability to the coastal environment from the inherent hazards than previous assessments by different researchers. The study has also identified a number of possible environmentally adoptable management interventions as a part of its sustainable solutions. The findings of this study are significant in understanding the retardation in the growth of the delta and environmental problems arising out of the inherent hazards of the coastal zone in a deltaic region. The study also suggests the significance of using open-source satellite data and geo-informatics-based CHW and DSAS in assessing the vulnerability of environmental degradation for integrated coastal zone management.KeywordsBiophysical environmentClimate changeCoastal hazard wheelGeographic information systemIntegrated coastal zone management