Surface sediment resuspension and suspended sediment transportation mechanism in the waters around Miaodao Strait

Based on the hydrological and sediment measurement data, characteristics of spatiotemporal distributions and variations of suspended sediment concentration and particle size around Miaodao Strait in Bohai Sea were analyzed. By using formulas of suspended sediment settlement, sediment incipient velocity, resuspension flux, and settlement flux, and the flux mechanism decomposition method, the resuspension flux, sedimentation flux, and suspended sediment transport capacity in the study area were calculated. The characteristics and dynamic mechanism of surface sediment resuspension and suspended sediment transport were analyzed. Results reveal a strong relationship between the periodic changes in the suspended sediment concentration and the tidal current velocity. The bottom layer responds obviously to high velocity while the surface layer responds obviously to low velocity. The phenomenon of single particle sedimentation of suspended sediment is not obvious. The hydrodynamic conditions in the sea areas are suitable for flocculation and sedimentation of suspended sediments except for the Miaodao Strait, and are mainly dominated by middle and bottom flocculation and sedimentation. The effect of surface sediment resuspension on the concentration of suspended sediment in the nearshore shallow water area and the sea area around the Miaodao Strait is significantly higher than that in other sea areas. The transport of suspended sediment is mainly advection transport and supplemented by vertical net circulation. In the southern side of Miaodao Strait, sediments are transported to the Yellow Sea, while those on the northern side to the Bohai Sea. The net transport of suspended sediment is mainly from the waterway to the shoals on both sides.