Shoreline Changes Along Bhitarkanika Sanctuary, North Odisha Coast, India

This study focuses on the long-term and decadal changes to the shoreline along the coast of the Bhitarkanika Sanctuary (BS). The statistical parameters such as net shoreline movement (NSM) and linear regression rate (LRR) were computed along 37.8 km stretch of the BS coast using the Digital Shoreline Analysis System (DSAS) software. About 81.7% of the shore eroded between 1975 and 1989, but between 1989 to 2005 and 2005 to 2020, this percentage significantly increased. However, there is a downward trend in the accretion percentage. The rate of erosion was highest between 2010 and 2020, followed by 1989–2000 and 2000–2010. However, accretion was greater during the period 1975–1989 than the recent decadal cyclic changes. The study revealed that the BS coast’s shoreline is rapidly eroding over time. The BS coast is eroding overall, except a small section at the Hansua River mouth that shows accretion at a maximum rate of 12.43 m/yr from 1975 to 2020. This river system’s massive sediment load could be the cause of nearby coastal expansion. The BS coast experienced a maximum erosion of 748.4 m at Pentha and a maximum accretion of 486.5 m north of the Hansua River between 1975 and 2020. The coast from Pentha to Satabhaya is heavily eroded (69.35%), with accretion making up a very small portion of the coastline. The study found that the Bhitarkanika coast experiences year-round coastal erosion as a result of the S and SE wave approach, northerly longshore transport, and episodic events.