Analyzing Channel Planform Dynamics through Geospatial Approaches over Gandak River Basin, India

The Gandak River, a significant transboundary river in the Indo-Gangetic plains, exhibits complex fluvial processes with frequent planform adjustments. This study examines the river’s morphological dynamics from 1975 to 2024, focusing on changes in total length and sinuosity index to analyze spatiotemporal variations. The river’s length fluctuated significantly, ranging from 309.79 km in 2010 to a peak of 343.88 km in 2005, highlighting patterns of elongation and contraction influenced by natural and anthropogenic factors. The sinuosity index declined from 1.57 in 1975 to 1.04 in 2024, indicating a shift toward a more linear flow regime. These changes reflect the interplay of sediment transport, hydrological variations, erosion, tectonic influences, and human activities, such as land use changes and infrastructure development. The reduced sinuosity suggests declining floodplain connectivity and altered sediment transport, with implications for river basin management, water resources, and habitat stability. This study underscores the importance of geospatial and hydrological assessments in understanding long-term river morphology trends and informing sustainable river management strategies. Keywords: River morphology, Sediment transport, Hydrological variations, Floodplain connectivity, River management.