Numerical Simulation Research On The Impacts Of Man-made Island On Flood Propagation And Erosion-deposition Of Estuary

With the rapid socio-economic development, the land resources becomeincreasing depleted. And the marine area on Earth is about71%of the earth’s surface.So the way that open up the available land resource from the ocean can relieve thepressure caused by the increasing depletion of land resource. To expending livingspaces in the ocean, exploiting man-made island with a variety of functions is one ofthe most important way for those countries and areas which has a comparativelylimited land resources to develop and use marine resources. However, theconstruction of the man-made island project has some influence on the particularitiesof flood and erosion-deposition in the estuary or near the project area. Therefore, it’svery important to study the influence of the construction of man-made islands on theparticularities of flood and erosion-deposition in the estuary or near the project area.In the paper, as the research background of the building man-made island in TangRiver Estuary, the2-D horizontal numerical model was built to simulate the variationprocess of hydrodynamic and sediment erosion-deposition before and after theconstruction of the man-made island. Then we summary the influence law of theconstruction of man-made islands on the particularities of flood anderosion-deposition in the Tang River estuary. The main results are as the following:(1) The hydrodynamic numerical model and the hydrodynamic coupled withsediment mathematical model were built and validated by measured data. And thesimulation results agree well with the measured data. Therefore, the two models canbe used to simulate and predict the hydrodynamic, sediment transport anderosion-deposition process in Tang River estuary. And the models provide thecomputational tools for further study.(2) The hydrodynamic process before and after the construction of the man-madeisland in Tang River estuary was simulated by the hydrodynamic model under thecircumstances of superposition of50-years frequency flood and tide level. Bycomparing and analyzing the water level, flow velocity and flow direction around theproject area and estuary before and after the construction of man-made island, westudy the backwater range and backwater height in the river channel, estuary and theproject area. Thus the influence law of the construction of man-made islands on theparticularities of flood in the river channel, estuary and the project area can besummarized. Then further study on the influence of desilting works before the construction and lighthouse on flood propagation in the estuary was made.(3) The hydrodynamic coupled with sediment model was used to simulate theprocesses of sediment erosion-deposition before and after the construction of theman-made island in Tang River estuary under the circumstances of superposition of50-years frequency flood and tide level. By comparing and analyzing the change ofscour and silting amount around the project area and estuary before and after theconstruction of man-made island, we could study the situation of erosion anddeposition around the river channel, estuary and project area. And summed up theinfluence law of man-made island in Tang River estuary. Then the impact oflighthouse located in the east of man-made island on the erosion-deposition variationaround the man-made island was further discussed.