Development of a Coupled Wave-Hydrodynamic Model for the Coastal Waters of Bangladesh using Delft3D

Amin, M.K. and Hasan, G.M.J., 2024. Development of a coupled wave-hydrodynamic model for the coastal waters of Bangladesh using Delft3D. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 639-643. Charlotte (North Carolina), ISSN 0749-0208. The study of water movement and its dynamics within the Bay of Bengal (BoB) is crucial for addressing challenges related to sea level rise, water pollution, coastal flooding, sediment movement, etc. This study discusses the development of a 2D coupled wave-hydrodynamic model covering the greater bay area. The study utilizes the model extent by digitizing the shorelines from Google Earth. The bathymetric data was collected from GEBCO. The curvilinear grid was designed utilizing the Delft3D modeling suite. Daily discharge data was collected from the BWDB at Baruria Transit station in the Padma River and Bhairab Bazar station in the Upper Meghna River, and both were considered as the northern open boundaries in the model. The model's southern open boundary was forced by hourly water level data which was collected from the PSMSL. The developed model was calibrated using available tidal gauge data. The water levels due to waves were validated using significant wave heights and wave periods collected from the ECMWF for a year. The model results of tidal water level were validated against tide gauge records and showed good results for both dry and monsoon periods. The model is finally applied to simulate the flow pattern covering the whole coastal region for a year. It shows seasonal fluctuations in higher water levels and depth-averaged current velocities during the wet monsoon season. The study provides a nuanced understanding of hydrodynamic processes in the BoB. This enables stakeholders to undertake informed future research and develop resilient coastal management plans.