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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.

Based on the measured data from the hydrological stations of Qilian, Zhamashik, Huangzangsi and Yingluoxia on the main tributaries, this paper analyzed the characteristics of water and sediment in the basin where the Huangzangsi Water Control Project is located, such as small inter-annual variation of water volume, large inter-annual variation of sediment volume, uneven distribution of water and sediment volume in the year and the fact that the sediment volume mainly comes from flood period. The sediment erosion modulus method was used to calculate the annual amount of suspended sediment deposited in the reservoir to be 1.697 million tons. The recommended annual amount of bed load sediment is 0.339 million tons. On the basis of the measured data of reservoir water and sand from 1968 to 2012, 5 a water and sand series were selected from the 5 a water and sand series to form 50 a water and sand series with 5 a sliding calculation. The one-dimensional hydrodynamics sediment erosion and sedimentation calculation model was adopted for calculation. The sediment discharge ratio in the calculated period of the reservoir was 22.6%, the total sediment deposition in 50 a was 62.8 million m3, and the maximum sediment concentration in the daily reservoir was 6.84 kg/m3. The reservoir siltation form is delta siltation and the siltation elevation in front of the dam is 2 557 m. [ABSTRACT FROM AUTHOR]