The Effects Of Regulation And Reclamation In Qiantang Estuary On Storm Surge At Hangzhou Bay

The effect of large-scale regulation and reclamation projects in Qiantang Estuary on the tide, particularly storm surge at Hangzhou Bay, is studied based on the numerical model. The study provides guideline for decision-making on development and resource conservation of Qiantang Estuary and Hangzhou Bay.Firstly, the evolvement of reclamation projects is described, and the research on the impact of the reclamation is reviewed. The Mike21 model is applied in East China Sea to build a two-dimensional nonlinearized numerical model of coupling between storm surge and astronomical tide. The model's minimum grid spacing is set as 300m. The boundary conditions are determined by tide levels composed of eight main constituents. As the wide bottomland is at the coastland of Zhejiang province, the problem of moving boundary is solved by using the flooding-drying technique. Cartesian coordinates is adopted in the model. To minimize error of coordinates transformation, all grids, bathymetry and typhoon location are set in Beijing 1954 coordinates system. Five-case typhoons passing through Zhejiang province are used to verify the model. Nine stations in Zhejiang province are employed in the verification, which are located in 900m grid area except Zhapu in 300m grid area.Based on the model built, several computational schemes are proposed to simulate tide and storm surge at Hangzhou Bay. At first the major factors of the impact of reclamation are analyzed by applying approximate bathymetry. Then the real bathymetry are used to simulate the tide's change under the condition of spring and middle tide, and the storm surge's change under the condition of extremeness and probability of 1% due to existing reclamation. Finally...