A Study of Suspended Sediment Transport Characteristics in the Offshore of Yangtze Estuary

Estuarine offshore area is the gathering area of sediment which is from watershed into sea. There has important theoretical and practical significance about researching the transport characteristics and the variation trend of the suspended sediment concentration (SSC) in this area. On the basis of analyzing the long data about recent 50 years to the Yangtze estuarine offshore area, there are some results: in time aspects, the SSC in dry season is higher than it in flood season, and the SSC in spring tide is higher than it in neap tide; in longitudinal distribution aspects, there is a decreasing trend about SSC from west to east, and the decreasing level of the SSC is ever-reduced from west to east until the SSC remains basically low and unchanged in the east of 123 E; in transverse distribution aspects, the SSC has high locations. Furthermore, there has a preliminary discussion for the variation of the SSC in the offshore area with the reduce of the sediment from watershed, comparing with the last century(1950s, 1970s, 1980s, 1990s), the SSC in the offshore area has a reductive trend, it shows good consistency between the variation of the SSC in the estuarine offshore area and the decrease of sediment from the Yangtse River into sea.