Abstract: The impoundment of the Three Gorges Project (TGP) has altered water and sediment transport dynamics in the downstream channel.Based on series hydrological and river channel topography data, we analyze the evolution of major sandbars and discuss the underlying mechanisms in the Jingjiang River reach after TGP impoundment. Our findings reveal several key points: 1) In the two decades since TGP impoundment, suspended load significantly decreased in the Jingjiang River reach, leading to observable riverbed erosion and retreat of most sandbars, particularly those near the mainstream. 2) In major bifurcations, most branches deposited, with individual branches expanding. 3) Changes in water and sediment downstream of the TGP primarily influenced the retreat of sandbars. 4) Human activities, such as river sand excavation and channel regulation projects, have impacted branch evolution in the Jingjiang River in recent years. 5) Due to ongoing alterations in water and sediment, sandbars are expected to continue their current evolutionary trends over an extended period.

Key words: Three Gorges Project, Jingjiang River, sandbars, evolution characteristics, influencing factors