Regarding the potential threats to the stability of riverbeds of existing hydraulic structures caused by changes in the regional topography and sediment conditions in the Fujiangsha Waterway of the Yangtze River due to the deepwater channel project,especially local scouring risks from historical pile foundations.This study focuses on the residual pile groups at Tian Gang Wharf.A two-dimensional hydro-sediment model for the Ligang-Tianshenggang river reach is developed to predict the trend of riverbed erosion and deposition.The research results show that:1)In normal sediment-water years,sedimentation dominates in the shoal area near the wharf and within 200 m upstream and downstream,the upstream side experiences erosion,the downstream shoal area shows slight sedimentation,and a strip-shaped sedimentation zone appears about 300 m offshore.2)In high-flow years,scouring in the nearshore shoal area is more extensive than in normal hydro-sediment years,but sedimentation still primarily occurs within 100 m of the wharf front.The modeling technique involved in this study can provide references for numerical simulations of residual pile groups at similar wharves,and the research results can provide scientific support for pile groups treatment plan in renovation and expansion projects of similar wharves.