Effects On Hydrodynamic Environment Of The Large-scale Reclamation Projects In The Oujiang Estuary

The Oujiang Estuary is the economically developed, populous area in our country, with the development of the economy development, the problem of shortage of land resources and population growth has become increasingly prominent in recent years. At the same time, the beach resources are very broad in the Oujiang Estuary, which are important extended areas of Wenzhou City. So land reclamation is the good choice for Wenzhou City, which can ease this problem of increased population and decreased land. Though land reclamation provides valuable resource, it will also change the local topography, and bring influence to local hydrodynamic environments. Therefore, under the premise of minimizing the effect on the hydrodynamic characteristics of the surrounding waters, reasonable reclamation has a very important significance for the sustainable development of the Wenzhou City. Based on the MIKE technology platform, the paper simulates the hydrodynamic characteristics in the project of Oujiang Estuary Reclamation, which provides strong technical support for the feasibility of coastal reclamation. The main contents in this paper are as follows:(1) The runoff, tide, wave, and wind characteristics in the Oujiang Estuary were analyzed systematically, revealing the estuarine topography, hydrodynamic characteristics. And make a brief description of Oujiang development status.(2) The hydrodynamic module MIKE21Flow Model FM and wave module MIKE21SW in the MIKE software were made a detailed introduction. By the MIKE21/3platform, wave module coupled with the hydrodynamic module to establish the Oujiang two-dimensional mathematical model, which considering wind, waves, runoff and tide under unstructured grid.(3) Based on measured data, the model was verified, and the calculated results are in good agreement with the measured data. On the basis of the above, wave-current coupling mechanism in the Oujiang Estuary was studied. The studied show that, considered the effect of the wave-current coupling, the model reflect the hydrodynamic characteristics more realistically. To analyze the impact of the waves off the coast waters near the Oujiang, the propagation of the sea wave in Oujiang area was simulated. The studied show that, because of the role in the cover of many islands in the Oujiang estuary, most of the incident waves have little effect on the estuary waters, only the E and the S directional waves have larger effect. (4) The model was applied to the numerical simulation on hydrodynamic environment in the Wenzhou Shoal project, the changes of hydrodynamic characteristics in the Engineering surrounding waters was systematic analyzed. The analysis showed that, the cofferdam built by the project, Ling-ni levee and Wenzhou Shoal consistent with the strike. So the project will not have a large impact on the scope of the hydrodynamic characteristics in the Oujiang Estuary, only have impact on the vicinity of the project, but not obviously. In addition, the project also cut off the Wenzhou Shoal sediment channel sediment to waterways, which play a role in further reducing silt on the Oujiang waterway to the sea. Therefore, the engineering is not only feasible, but also advantageous.