<p>Sediment transport plays a critical role in shaping river morphology, influencing flood risk, navigation, and infrastructure stability especially in large alluvial rivers like the Ganga. This study presents a two-dimensional (2D) numerical simulation of suspended sediment transport for the Patna and Bhagalpur reaches of the Ganga River, regions severely affected by siltation and erosion. The primary objective was to quantify the spatial and temporal patterns of sediment dynamics and evaluate their implications for river management. A two-dimensional (2D) hydrodynamic and sediment transport model was applied using the MIKE 21 FM (2D) platform to simulate flow and sediment dynamics in the Ganga River between Patna and Bhagalpur. The model was calibrated and validated using field observations of water levels, flow velocities, and sediment concentrations. Simulation results reveal that high flow velocities during monsoon lead to significant sediment mobilization, while lateral floodplains experience deposition due to low-velocity conditions. The sediment transport patterns exhibit strong seasonal variation, with deposition hotspots identified near channel bars and inner bends. Sensitivity analysis highlights the importance of parameters such as settling velocity and sediment input concentration, which substantially influence deposition rates. The findings suggest that localized siltation near Patna and Bhagalpur could hinder navigation and exacerbate flood risks. The study emphasizes the need for continuous sediment monitoring and adaptive management practices to maintain channel capacity and minimize flood hazards. This work demonstrates the utility of 2D modeling for understanding sediment dynamics in complex river systems and offers actionable insights for improving sediment management strategies in the Ganga Basin.</p>