Abstract:The mode of sediment transport is complex in a fine sediment tidal estuary.The different forms of sediment transport are very important for the study of estuarine evolution and channel siltation.Under tidal and wave conditions,this paper discusses the characteristics of bedload transport of non-cohesive sediment,movement of near bed high concentration suspended cohesive sediment layer and fluid mud layer,and characteristic,occurrence condition and transport rule of other sediment.Based on the hydrodynamic condition in the South Channel of the Yangtze Estuary and the result of previous flume study,this paper estimates the transversal sediment transport of high concentration suspended sediment from the nearby shoals into the channel when the salinity of the main channel is higher than that of the shoal.The result is basically in agreement with the actual result of channel sedimentation.