Impacts of channel dredging on hydrodynamics and sediment dynamics in the main channels of the Jiaojiang River Estuary in China  

作　　者：Yanming Yao Xueqian Chen Jinxiong Yuan Li Li Weibing Guan 

机构地区：[1]Ocean College,Zhejiang University,Zhoushan 316021,China [2]Hangzhou Xi’ao Environmental Science and Technology Company Limited,Hangzhou,310011,China [3]State Key Laboratory of Satellite Ocean Environmental Dynamics,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310058,China

出　　处：《Acta Oceanologica Sinica》2023年第9期132-144,共13页海洋学报（英文版）

基　　金：The National Key Research and Development Program of China under contract No. 2020YFD0900803;the National Natural Science Foundation of China under contract Nos 41976157 and 42076177;the Science Technology Department of Zhejiang Province under contract No. 2022C03044;the State Key Laboratory of Satellite Ocean Environment Dynamics of the Ministry of Natural Resources of China under contract No. QNHX1807。

摘　　要：Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effects of different dredging schemes on siltation were assessed through numerical modeling. The sediment model of the Jiaojiang River Estuary utilized an optimized bottom boundary layer model that considered the bed sediment grain size and fluid mud, and this model was calibrated using field data. Result reveal that channel dredging modifies the flow velocity inside and around the channel by changing the bathymetry;subsequently, this affects the residual current, bed stress, suspended sediment concentration, and sediment fluxes. Increasing the dredging depth and width increases the net sediment fluxes into the channel and dredging depth has a greater influence on the channel siltation thickness. When the dredging depth is 8.4 m or11.4 m, the average siltation thickness of the channel is 0.07 m or 0.15 m per mouth respectively. The parallel movement of the channel has small effects on the siltation volume during the simulation period. The sediment deposits in the channel primarily originates from the tidal flats, through bottom sediment fluxes. Vertical net circulation has a dominant impact on siltation because the difference of horizontal current of each layer on the longitudinal section of the channel increases, which intensifies the lateral sediment transport between the shoal and channel. The influence of vertical frictional dissipation on the lateral circulation at the feature points accounts for more than 50% before dredging, while the non-linear advective term is dominant after dredging. Tidal pumping mainly affects the longitudinal sediment fluxes in the channel. These results can be used for channel management and planning for similar estuaries worldwide.

关 键 词：sediment dynamics channel dredging bottom boundary layer SILTATION Jiaojiang River Estuary 

分 类 号：P73[天文地球—海洋科学]