Aiming at the problem of sedimentation in excavated basin,sediment model tests are conducted to investigate the siltation patterns of excavated basins under different water and sediment conditions.The results indicate that in the year of heavy water and sand,such as 1963,the sedimentation in the harbor basin reached 74,200 m3,with the average silting thickness was about 0.4-0.5 m.Sediment mainly accumulated near the entrance of the harbor basin and within the original main river channel,reaching up to 1.3 m in the local area.However,the sedimentation thickness within the harbor basin was only 0.1-0.2 m.After 13 years of operation,sedimentation occurred in the whole section of the river,with the average silting thickness was about 1.0 m and up to 2.0 m in some areas.The main areas of sediment accumulation remained unchanged.Specifically,an area of approximately 60 m at the entrance of the harbor basin experienced significant elevation after sedimentation,potentially causing navigation obstacles during periods of low water levels and small flow rates.As the years of operation increases,the sediment in the harbor basin accumulates cumulatively and depth of the harbor basin is gradually decreasing.In the mountainous river,it is feasible to construct excavated basins utilizing backwater eddies,and sediment accumulation can be controlled.