Google Map Based Morphodynamics Analysis of Selected Reaches of the Teesta River

Abstract Understanding spatial and temporal variability of river morphodynamics is essential for sustainable river management, particularly in highly dynamic alluvial rivers. The present study investigates zone-wise morphodynamic behavior of a 6.42 km reach of the Teesta River using multi-temporal Google Earth Pro imagery and secondary hydrological data. The study reach was divided into three zones based on changes in plane form characteristics and channel behavior. Zone-wise analyses of river width, longitudinal slope, stream power, specific stream power, bank migration, and erosion–deposition dynamics were carried out for the periods 2011–2016, 2016–2021, and 2021–2025. Bank line positions were manually digitized to quantify lateral migration, while erosion and deposition areas were delineated using polygon overlay techniques. Stream power and specific stream power were estimated using representative discharge values and zone-wise slope and width measurements. Results indicate pronounced spatial variability in morphodynamic processes along the study reach. Zone 2 exhibits the highest stream power and bank migration rates, corresponding to dominant erosion, whereas Zone 3 shows relatively lower energy conditions with localized deposition. Temporal analysis reveals increasing bank instability in recent years, particularly in the middle reach. The study demonstrates the effectiveness of Google Earth Pro as a low-cost tool for river morphodynamic assessment and provides valuable insights for riverbank management and planning in braided river systems. Keywords: Teesta River, River Morphodynamics, Bank Migration, Stream Power, Erosion–Deposition, Google Earth Pro.