Earth Observation-Based Analysis and Modelling of Coastline Erosion and Accretion Along the Parts of the East Coast of India

Abstract. This study examines the patterns and processes of coastal erosion and accretion along the West Bengal coast of India from 1990 to 2020, a region characterized by its dynamic geomorphology and significant socio-economic importance. The West Bengal coast, stretches approximately 157.5 km parallel to latitude along the northern Bay of Bengal, Over the past three decades, this region has experienced considerable changes. To assess the coastal changes, a multi-temporal analysis was conducted using satellite imagery from Landsat images, supplemented by Geospatial techniques, and GIS, which were employed to map and quantify the rates of erosion and accretion. Shoreline positions were delineated at decadal intervals, and changes were analyzed using the Digital Shoreline Analysis System (DSAS) to calculate erosion and accretion rates. The analysis revealed significant spatial and temporal variability in coastal erosion and accretion along the West Bengal coast. The South 24 Parganas is combined with multiple islands and the mainland. We have only considered the specific coastal islands and coastal locations where the historical shorelines were extracted. Ghoramara Islands, Sagar Islands, Jambaudwip Islands, and other islands are taken into four divisions. The East Medinipur district is divided into six divisions and Nayachar Island was also calculated separately. The total erosion of the study area is 2.62 km per year in 30 years and the total accretion of the study area is 1.18 km per year. In 1990 the length of the entire study area was 51.16 km and in 2000 the shoreline length was 52.72 km and the length of the shoreline in 2010 was 50.68 km lastly in 2020 the shoreline length of the study area was 45.51 km. It is the entire study area facing erosion rather than accretion. The study highlights the geographical areas where erosion and accretion take place.