River bank erosion vulnerability demarcation based on the sensitivity analysis of geotechnical parameters: Majuli Island, India

Abstract

The present study assesses the vulnerability of the river bank area most sensitive to erosion by combining the data obtained from existing literature and performing numerical simulation using finite element-based numerical code. Various geotechnical parameters, like average particle size (D50), Plasticity Index (PI), Elastic Modulus (E), Dry Unit Weight (γd) or Saturated Unit Weight (γsat), Coefficient of Permeability (k), Undrained Shear Strength (cu), Moisture Content (w%) and soil types based on the Unified Soil Classification System (USCS), were taken into account. Weighted Ranking Analysis (WRA) was performed based on the sensitivity of relevant geotechnical factors affecting bank erosion. The results indicate that the areas influenced by the Subansiri River (western bank) and the Brahmaputra River (southern bank) fall in the highly vulnerable zone category, while the Luhit and Kherkutia Suti Rivers (northern bank) fall in the moderately vulnerable category to river bank erosion.