Influence of Hengsha Passage on Sediment Deposition in the Upper Reach of the Deepwater Navigation Channel in the Changjiang River Estuary

Based on the data of water depth in the South Branch and the Hengsha Passage, and the flow spilt ratio of the North Passage and the South Passage, the reasons for the sediment deposition in the upper reach of the Deepwater Navigation Channel in the Changjiang River Estuary are explored. The study shows the influence of the development of the Hengsha Passage is significant. The development of Hengsha Passage causes the increase of sediment and water exchange between the North Channel and the North Passage, which weakens the sediment and water exchange between the North Channel and the North Passage, and enhances the sediment silting in the upper reach of the Deepwater Navigation Channel. The development of Hengsha Passage also causes the scour of the upper reach of the South Passage, which weakens the ebb tide entering into the North Passage and further strengthens the sediment deposition in the upper reach of the Deepwater Navigation Channel. On the other hand, the Coriolis force and V-shaped diversion dike at the head of the Deepwater Navigation Channel also contribute the sediment deposition in the upper reach of the Deepwater Navigation Channel.