Characteristics of recent flow and suspended sediment transport in beachs and channels of South Channel of Yangtze River Estuary

In order to understand the recent evolution trend of Yangtze River Estuary,according to the measured hydrological and sediment data on beach and channels of South Channel in flood and dry seasons of 2005,2006 and 2010,the hydrodynamic conditions and the temporal-spatial distribution of suspended sediment in main channel and shallow beach are analyzed.The mechanism decomposition method is adopted to study the sediment transport and exchange mechanism.The result shows that the flow is reciprocated and the ebb current velocity is larger.Flow velocity process changes with depth,resulting in different sediment-carrying capacity and sediment transport process in different areas.Sediment is transported mainly by advection term,but tidal pumping occupies an important position of suspended sediment transport in the south passage zone.The sediment flows out at main channel and comes in at shallow areas,which makes the front of Nanhui shoal deposit slowly.