Stability Analyses of Alluvial Riverbanks of Majuli Island, Upper Assam, India

Riverbank erosion is a continuous process in which its stability is critical throughout the course of the river. The purpose of this study is to examine and assess the stability of the riverbanks of Majuli, the world's largest riverine island, which is encircled by the river Brahmaputra. Because the river Brahmaputra and its tributaries are primarily made up of alluvial composites, hence vast areas of riverbanks are vulnerable to instability and erosion. Riverbank stability evaluations are conducted utilizing Culman-type analyses of steep, cohesive riverbanks, as proposed by Osman and Thorne (J Hydraul Eng, ASCE,114(2):134–150 [1]). Bank angles ranging from 35° to 85° are evaluated for stability analyses. The factor of safety (FOS) for each riverbank and the critical bank angle (for FOS = 1) are computed using the appropriate formulas. The outcome of these analyses revealed that the banks are in a highly unstable state and thereby adopting a suitable factor of safety, necessary measures should be adopted for the protection of the riverbanks from future erosion.