A Flow-Sediment Numerical Model Using One and Two Dimensions for the Yongding New Estuary

This paper derived the continuity and momentum equations of solid–liquid two-phase flows using infinitesimal body analysis and obtained well-posed equations of two-dimensional (2D) flow-sediment movement. Based on the theory of solid–liquid two-phase flow, the momentum equations of the bedload sediment were deduced and a closed form of the 2D total sediment model equations was established. Then, the exchange mechanism of suspended sediment and bedload sediment and their computational method were elaborated on in great detail. Combined with the basic theory of one-dimensional (1D) flow-sediment movement, a flow-sediment numerical model of one and two dimensions was established for the region of Yongding New Estuary. A series of model verifications were carried out, which showed that the model can be adopted to simulate the flow-sediment movement in this region. This model was then applied for the environmental assessment of Taida Sea Reclamation Project. The conclusions indicate that the backwater effects of the proposed construction scheme would be fairly small and that the deposition amount in the river would be greatly reduced owing to the source of alongshore sediment transport being blocked by the project. This study provides a scientific model and method for the feasibility study and environmental assessments of construction projects.