The project reach encompassing the Cao’e River ship lock features complex hydrological and sedimentary conditions.It is a meandering section subject to strong tidal bores,high sediment loads,and significant riverbed erosion and deposition.To address the severe siltation issue downstream of the lock resulting from high sediment concentrations,this study analyzes measured riverbed topography below the Cao’e River Gate,conducts flushing tests,and performs sediment deposition calculations.These analyses reveals the patterns of riverbed erosion and siltation,and investigates key issues such as the stability of the riverbed in the ship lock approach channel.On-site flushing test analysis indicate that during the initial phase of spring tide sedimentation within the area 115-200 m downstream of the Cao’e River Gate,the average sedimentation rate ranges from 20.8 to 21.8 cm/d.Using an empirical sedimentation formula,the calculated average siltation amplitude below the outlet lock reaches 17 cm/d.To mitigate the problem of intense siltation below the lock,the construction of a water storage and sediment flushing basin is proposed as an effective sediment control measure.Calculations estimate that with a monthly average flushing discharge of 8.13 million cubic meters,the approach channel riverbed can be maintained at an elevation of approximately -1.7 m.These findings provide reference for the future design and research of sedimentation prevention and reduction in similar ship lock projects.