Author(s): Weiqi Dai, Jianfeng Tao, Kun Zhao, Qin Zhang, Yu Kuai
Linked Author(s): Weiqi Dai
Keywords: Tide flat reclamation, hydrodynamic characteristics, seabed evolution, wave-current effect
Abstract: Jiaojiang Estuary is a typical tidal-dominated estuary. With the increasing demand of land resource, a series of large-scale tidal flat reclamation has been conducted along the coast of Jiaojiang Estuary, which may lead to the changes of hydrodynamic characteristics, suspended sediment transport and local topography. A two-dimensional mathematical model is developed to simulate the tidal current, suspended sediment transportation and wave in Jiaojiang Estuary in this study. Results of the tidal current field and suspended sediment concentration (SSC) are compared before and after the tidal flat reclamation. The effect of large-scale reclamation on the hydrodynamic characteristics are discussed based on a 2-d numerical model coupling processes of tide current, wave, and sediment-transport, and the impact of reclamations are explored. Results show that the tidal prism of the estuary is reduced after the reclamation, which leads to the decrease of tidal velocity. The reduction of tidal prism also diminishes the tidal level. Besides, the reclamation narrows the cross-sections of the channel, so that the seabed is eroded at the mouth and then accumulates in the inland river region. As a result, the suspended sediment concentration increases, despite that the tidal flow is weakened. Compared with seabed after the reclamation when considering tide current only, more topographic change of the river bed is observed when combining wave and tide current. Waves play important roles in shaping the topography in Taizhou Bay which is a macro-tidal sea area. The changes of hydrodynamics and sediment concentration are the main dynamic mechanism in scouring and silting evolution of the Jiaojiang Estuary
Year: 2017