Morphological changes in the hazardous zones of the Ganga and the Brahmaputra Rivers in East and Northeast India

The Ganga–Brahmaputra river basin is the second-largest hydrological region in the world. This is an integrated, trans-boundary drainage system with a common terminus of two major river systems, i.e., the Ganga and the Brahmaputra. Both the rivers are undergoing a process of shifting in their courses over time, thereby making certain stretches in their respective flow paths hazardous in nature. This study analyzes the factors that influence these shifting patterns at the two most hazardous sites located along both these rivers. The study focuses on the morphological changes in these hazardous zones (Malda along the Ganga in West Bengal and Morigaon along Brahmaputra in Assam) by calculating the bank-line migration, erosion-accretion, lateral shift, land loss, and related issues. Topographical map and multispectral Landsat imageries were used for certain time periods (1955 to 2020) to analyze the chronological changes in the river morphology. Remote sensing (RS) and geographic information system (GIS) were used to evaluate and analyze the scenario in the study area.