The Impacts Of Man-made Island Projects On Current And Sand Of Estuary And Coastal Environment

In recent years, with an enormous population growth and rapid economic development, the expansion of non-agricultural construction land and the sharp drop in the amount of cultivated land, environmental degradation, resource shortages and the growing demand of people's living standard, these contradictions become increasingly serious.; therefore, exploiting the ocean space pays a key role in mitigating those contradictions, optimizing the ecological environment and the protection of food security, maintaining and coordinating the sustainable social and economic development; However, the traditional methods-Coast reclamation cannot make full use of our precious marine beach, maintain the sustainable development ,what is more it also caused some degree of negative impact on the marine environment. Therefore, utilizing the sea in an appropriate way is a direction in the future. On the one hand, the development and utilization of Coast reclamation should be strictly controlled; on the other hand, constructing artificial island which render a relatively less impact on the ecological environment should replace the traditional way of coast reclamation, it also should be considered as the main mode of utilizing marine, and an important means of expanding living space.When compared to the traditional way of coastal reclamation, the construction of artificial island (group) pay more attention to marine hydrology, the change of marine power, the interaction between the artificial island (group) and the marine environment, the transporting of coastal sediment ,geomorphology evolution and other factors. Especially when build man-made island near the mouth (s) of the river, additional factors need to be considered, water and sediment environment become more complex; So more detailed research about the impact on the coastal water and sediment environmental should be explored when constructing artificial Island (s) near the estuary.This article summarize the status and development trends of the artificial island (group) firstly, on this basis, the author take a representative artificial islands (group) as an example, establish a comprehensive mathematical model to conduct some research on the runoff waters, wind flow, ocean trend which are near the artificial island (group) and the corresponding stream sediment movement, analyze the level of environmental impact on the estuary, coastal water and sediment which are engendered by the artificial island (group), explore the basic law of the estuary and the movement of sediment under the impact of artificial island (s), provide the basis for the planning and design the artificial island (group). The concrete results and conclusions are as follows:In order to make sure the mathematical model whether to fit the realities or not, I compare the result calculated from the mathematical model to the measured data of the three representative points around the artificial island (group) near the estuary. It verified that the mathematical model agrees well. It indicates that the model can be used to predict the laws of the estuarine sediment transport and the trends of the evolution of coastal to some extent.The results of the numerical simulation show that the ebb tidal current decide the direction of the overall sediment transport; When the artificial island(s) built, the pathway of the runoff discharging to the sea may be changed; Due to the effect of the artificial islands (group), a stable tidal inlet will come into being between the estuary and the artificial islands (group) and the evolution law of the shallow shoal outside the estuary shows as "Silting in the East and scouring in the West, mainly Silting "; The storm cross-sections of these coasts both sides of the estuary on presents the law respectively as " Narrow in the east and wide in the west,", while the normal wave cross-sections shows the law as "Advancing in the west and retrograding in the east "; The artificial island (group) has the most chance of evolving into a tombolo, meanwhile, the estuary channel will be also troubled by the sediment accumulation.