Abstract: Under the joint influences of the Changjiang River and ocean, the significant sandbar system has been produced in the river mouth, and the submarine delta in the outer deep region. Hengsha Shoal is one of the most important components in this sandbar system. The suspended sediment concentration is not only influenced by the upstream sediment input, but also affected by the storm surge and strong wind. The SSC during spring tide is mainly bigger than that during neap tide. And the SSC of wintertime is higher than summer. The averaged SSC at the 5 m isobath is about 0.459 kg/m3. The SSC shows a significant decreasing trend at the seaward direction. Under the decreasing input from the Changjiang River recently, some part of the seabed shows a erosion pattern. The bed of Hengsha Shoal is mainly composited of silt, and the submarine delta is consisted of silt and clay. The submarine delta could be excavated for harbor and channel, which is favorable for the construction of planed harbor.

Key words: Changjiang Estuary, Hengsha Shoal, Submarine delta, SSC, sedimentation