Study on Numerical Simulation and Prediction of Silt Return in Hangzhou Bay Beach

Aiming at the problems of siltation promotion and siltation return in the beach area of Hangzhou Bay, a numerical calculation model of hydrodynamic and scour and siltation in the south bank of Ningbo Bay was constructed, and the reliability of the short-term scour and siltation numerical calculation model was verified by combining with the field measured scour and siltation data, so as to obtain the natural siltation situation in this area under a longer time scale in the future. Meanwhile, the siltation promotion scheme was selected by comparing with artificial embankment construction. The research results show that the restoration effect of natural silt beach under the action of excavation diversion is remarkable, and the construction of barrier has a significant effect on the retention and sedimentation of sediment in the trench. After the construction of the barrier with a height of -2.22m, the average thickness of sediment promotion in the low-lying area reaches 0.22m, and the elevation of seabed in the low-lying area can reach about 2.5m. Therefore, it is particularly effective for the sediment deposition in low-lying areas in the high sediment content sea area to adopt the method of natural diversion and separation embankment.