Abstract: Diaoyuzui Shoal, located in a large curved passageway in the fluctuating backwater area of the Three Gorges Reservoir, was featured with curved and dangerous waterway and rapid current. A maintenance dredging project was first carried out in 2018. In this paper we analyzed the rationality, adaptability and sustainability of the dredging work based on summarizing the characteristics of shoals obstructing navigation, the dredging plan and the implementation process, etc., and then evaluated the effect of the dredging work and summarized its problems and shortcomings. Results demonstrated that the dredging design was well adaptive to riverbed evolution and annual water-sediment transport rules; the dredging was conducted when the water level of the Three Gorges storage reach rose, which not only alleviated the contradiction between construction and navigation, but also doubled the effect by taking the advantage of post-flood scouring. Nevertheless, the stability and sustainability of the channel are difficult to be maintained because the dredging project does not change the water and sediment conditions and boundary conditions that cause the riverbed evolution. Therefore, we suggested to strengthen the underwater terrain observation of the reach and carry out waterway regulation works in time according to the evolution trend of the shoal.

Key words: maintenance dredging, Yangtze River waterway, design of dredging scheme, timing of dredging, fluctuating backwater area of reservoir, Diaoyuzui shoal