Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River Estuary and its adjacent waters

The detailed analysis of suspended sediment concentration variations over a year period is presented from eight observation stations within the Yangtze River estuary and its adjacent waters, combined with hydrodynamic regime of the estuary. Spatially, the suspended sediment concentration from Xuliujing downward to Hangzhou Bay increases constantly, and the suspended sediment in the inner estuary shows higher concentration during summer than during winter, while in the outer estuary it shows higher concentration during winter than during summer, and the magnitude is greater in the outer estuary than in the inner estuary, and greater in the Hangzhou Bay than in the Yangtze Estuary. The sediments from the Yangtze River are resuspended due to marine dynamic actions including tidal current and wind wave. Temporally, the suspended sediment concentrations show a neap-spring tidal cycle and seasonal fluctuations. Furthermore, it is concluded that wind waves and tidal currents are the two predominant factors related to sediment resuspension and control of the changes of suspended sediment concentration, in which tidal currents control the neap-spring tidal cycle, and wind waves control the seasonal fluctuation. The river water discharge and marine dynamics control spatial distribution of suspended sediment concentrations.