Geospatial assessment on the changing pattern of geomorphology: A case study on the world’s largest river island Majuli

Abstract

Majuli, the world’s largest inhabited river island, is bounded by the river Brahmaputra in the south, river Subansiri in the northwest, and the Kherkatia Suti (an anabranch of the river Brahmaputra) in the northeast. Because of its unique geographical occurrence and part of the vast dynamic river system of the Brahmaputra basin, it has faced erosion problems since historical times and possesses a significant concern. The paper aims to study the historical changes in bank line shifting around Majuli and the associated geomorphic changes using multi-temporal satellite remote sensing data spanning from 1975 to 2021. The observation has revealed a dramatic bank line shifting with an erosion rate of 2.41 km2/year and a deposition rate of 0.75 km2/year. An enormous shrinking of the geomorphic area occurs around the island, with 563.69 km2 in 1975 to 422.10 km2 in 2021. The annual rate of land degradation of Majuli island between 1975 and 2021 of 3.07 km2/ year. There is an urgent need for multifaceted approaches of effective spatial planning to protect this geoheritage from being further engulfed by the river Brahmaputra and Subansiri.