Posters 1

[Poster 1-25] Application of ROMS-CSTMS to Analyze Sediment Transport Dynamics in the Northern Bay of Bengal

*Mohd Imaran¹ (1. IIT KHARAGPUR AND SWANSAT (India))

The monsoonal rivers of India at its head are contributing to the sediment load and massive freshwater inflows into the Northern Bay of Bengal (NBoB). The integrated community sediment transport modelling system (CSTMS), a submodule of the Regional Ocean Modelling System (ROMS), was applied to analyze the spatial dispersal of cohesive (silt) and noncohesive (sand) sediment. We simulated the model under three alternative scenarios: (1) river-influenced, (2) non-river-influenced, and (3) non-tidal-influenced to understand the sediment dynamics close to the coast. The Ganges-Brahmaputra, Mahanadi, and Irrawaddy Rivers revealed a very high vertically averaged silt and very low sand at their mouths while the presence of the river was in simulation. Additionally, where the averaged silt concentration is very high, the bottom stress brought on by wave-current interaction is also strong. Furthermore, bottom stress is the major factor of sediment migration near the coast. Moreover, the averaged silt and sand are also noticeably less where the Ganges and Brahmaputra meet, as are the Mahanadi and Irrawaddy rivers when the rivers are not in the simulation. The ROMS-CSTMS model for the NBoB is then used to perform numerical simulations under three scenarios: with and without rivers and without tide. The findings show that patterns of sediment transport, erosion, and accretion are strongly impacted by bottom stress brought on by the interaction of waves and currents. A high sediment load can impact water quality and marine life; therefore, to manage the shoreline, plan the harbour, and dredge the silt deposited for the ship passages to the port, erosion and accretion of the shore and the sea bottom are crucial.