Threats to coastal communities of Mahanadi delta due to imminent consequences of erosion - Present and near future

Abstract

Coastal erosion is a natural hazard which causes significant loss to properties as well as coastal habitats. Coastal districts of Mahanadi delta, one of the most populated deltas of the Indian subcontinent, are suffering from the ill effects of coastal erosion. An important amount of assets is being lost every year along with forced migration of huge portions of coastal communities due to erosion. An attempt has been made in this study to predict the future coastline of the Mahanadi Delta based on historical trends. Historical coastlines of the delta have been extracted using semi-automated Tasselled Cap technique from the LANDSAT satellite imageries of the year 1990, 1995, 2000, 2006 and 2010. Using Digital Shoreline Assessment System (DSAS) tool of USGS, the trend of the coastline has been assessed in the form of End Point Rate (EPR) and Linear Regression Rate (LRR). A hybrid methodology has been adopted using statistical (EPR) and trigonometric functions to predict the future positions of the coastlines of the years 2020, 2035 and 2050. The result showed that most of the coastline (≈65%) is facing erosion at present. The predicted outcome shows that by the end of year 2050 the erosion scenario will worsen which in turn would lead to very high erosion risk for 30% of the total coastal mouzas (small administrative blocks). This study revealed the coastal erosion trend of Mahanadi delta and based on the predicted coastlines it can be inferred that the coastal communities in near future would be facing substantial threat due to erosion particularly in areas surrounding Puri (a renowned tourist pilgrimage) and Paradwip (one of the busiest ports and harbours of the country).

Keywords: Coastal communities; Coastal erosion; DSAS; EPR; LRR; Mahanadi Delta.