Sediment Transport Associated with the Baroclinic Term in the 3D-Hydrodynamic Circulation Model: Study Case for Idealized Estuary

This work provides a general hydrodynamic circulation model that can be used to understand density driven flows, which may arise in the case of suspension of fine-grained materials. The research is expected to provide a better understanding of the characteristics of spatial and temporal variability of current, which is to be associated with the period of ebb and flood tidal cycles with the inclusion of baroclinic term. The understanding of this process provides a basis for determining how the water circulation three-dimensionally controls the hydrodynamics of the system and ultimately the transport of suspended material and soluble materials. The model development includes extending the existing three-dimensional (3D) ADCIRC Hydrodynamic Model with (1) baroclinic forcing term and (2) transport module of suspended and soluble materials. The transport module covers the erosion, material suspension and deposition processes for both cohesive and non-cohesive type sediments. In the study case of an idealized rectangular basin, the model provides less than 6% error of mass conservation for eroded, suspended and deposited material sediment. The influence of the baroclinic forcing on the distribution of suspended sediment, mainly for cohesive type sediment, under influence of the tidal current and normal flux fresh riverine water was demonstrated. The inclusion of the baroclinic term might increase the total net transport of suspended cohesive sediment.