Abstract: The aim of this research is to obtain the evolution characteristics of Chongqing segment of Wujiang River and its influence on navigation in recent years. On the basis of prototype observation of sediment from 2016 to 2020 together with the change of runoff and sediment characteristics, the characteristics of sediment erosion and deposition and the law of river evolution are analyzed. The research findings are presented as follows: 1) In addition to the main flood season, the water level fluctuation period of the Three Gorges Reservoir and the end of flood season see most sediment transport. 2) In Wulong Gorge segment in the upstream, the river bed showed a declining trend, while the estuary bed an upward trend, and the river channel slope in general a gentle trend. 3) The annual sediment scouring and silting in wide reaches changes more significantly than that in canyons. 4) Perennial backwater channel is subjected to inferior sand conditions, basically in siltation. 5) The erosion and deposition of river sediment in the upstream of the fluctuating backwater area is mainly controlled by river morphology. In conclusion, from the perspective of evolution trend, the current incoming water and sediment conditions are conducive to reducing river sediment deposition. The erosion and deposition in some critical dangerous shoal segments develops gently, the river regime is generally stable, and the river evolution has little impact on shipping.

Key words: sediment erosion and deposition, fluvial processes, navigation, prototype observation, downstream of Wujiang River