The Characteristics And Simulation Of Tidal Hydrodynamics And Suspended Sediment In Winter In The Luotou Strait Of Zhoushan Islands Area

Sediment movement is an important natural phenomenon in the estuarine and coastal areas,so there has an important significance to learn and find out the characteristics and the law of motion of sediment for the development of these areas and the protection of the marine environment.Based on the hydrology and sediment data in the Luotou strait of Zhoushan Islands in2005winter, the characteristics of hydrodynamics and suspended sediment transport were discussed,then establish a2D tidal current and suspended sediment model which including the Changjiang estuary and Hangzhou Bay and take the Luotou strait as the key research area, further discussed the characteristics of hydrodynamics and suspended sediment distribution and transport.The tidal current condition is compelx in the northern and southern nearshore area of the Luotou strait because of the special topography.Based on the analysis result of suspended and bottom sediment,the net suspended sediment transport direction in the strait is the ebb tidal current direction,but there is an opposite suspended sediment transport direction in the nearshore area because of the unbalanced flood and ebb tidal current.The flow in the strait shows the obvious characters of a to-and-fro current,there is a difference between the main streams of flood and ebb tidal current because of the special topography.For the same reason, the residual current is also having an opposite directions in the strait,which separately pointed to the Hangzhou Bay and open sea.The sediment concentration is decreased from the west part to the east part of the Luotou strait,there are two opposite trends of the net sediment transport in the strait because of the difference between the main stream of the flood and ebb tidal current. Based on the computed result of the profile sediment transport at the two entrances of the strait,it is showed that the total net sediment transport direction is the ebb tidal current direction.There is a good correlation of the sediment concentration and the process of flood and ebb curremt which means that the advective sediment transport is the major function of the sediment transport in the strait and make the Luotou strait as the main channel of sediment transport from the Changjiang Estuary and Hangzhou Bay.to the open sea.