Study On The Siltation In Dock Harbor In The Strong Tidal Bore Reach Of Qiantang Estuary

Based on the analysis of hydrographic dynamical conditions and sediment character of Qiantang estuary, for studying to build a dock harbor in the strong tidal bore section of the Qiantang estuary, using physical model experiments to study the siltation in the harbor, and discussing possible dredging measures. The results provide the technical basis for design and operation of the dock harbor.After comprehensive consideration, to determine the scale of the physical model asλl,=200 andλh=80, to study the siltation of two project plans in the condition of composed tidal current.The results of physical model experiments show that,10-day deposition thickness was less than 0.10m in the harbor basin on average, about 0.15-0.25m in chamber, while the deposition thickness in the entrance varied according to plans and areas with an average of over 0.50m and a maximum of 1.90m. The results of calculating methods show that, the average deposition thickness of spring tide, ordinary tide and neap tide could be 0.18m per day in the approach channel. Siltation in approach channel was so heavy that dredging was needed every one or two days. This paper proposes that jetting dredging is possible with building canals to conduct tidal flow so as to output the suspended sediment in the approach channel.