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A case study of bottom topography variation under wave current interaction in the vicinity of KinmenLin, Q.Yih 14 February 2008 (has links)
The bottom sediments near the coast of Taiwan Strait are mainly terrestrial origins. The sediment transport processes are controlled by the meteorology hydrology factors, including winds, waves, flows and sea level variations. This study is aimed to investigate the influence of wave-current interaction to the sediment dynamics in the vicinity Shuitou Harbor of Chinmen. Emphasize is placed on analysis of observed meteorology and hydrology data and the bottom topography.
The data used in this study are from the field observations during the development of Shuitou Harbor. The hourly data include winds, currents, waves and tides. Additional bottom topography surveys were carried out twice per year, one in April and the other in October. The period of time series data is between October, 2001 and April, 2006.
The results of the analyses showed that (1) During the period of northeast monsoon, deposit dominated in the northern part of the study area (Shuitou Harbor vicinity), while erosion dominated in the southern part. The deposition and erosion phenomena reversed during the period of southwest monsoon. (2) The bottom topography variations had higher correlation with the large waves and flows in the winter northeast monsoon season. (3) Winds correlate well with the large waves and flows in the winter, while the correlation is weak in the summer. (4) Resuspension of bottom sediments seems play a major role in the sediment transport, especially in the winter large wave condition. During persistent northeast monsoon, wave height increased significantly that bottom sediments were eroded and transported by the southward mean flow, erosion occurred (in the southern part of the study area). (5) There are two likely sources of sediment. The major source of sediment is from the north, brought by the southward China coastal current in winter. The second source of sediment is from the south, Jiulong River, which occurred mostly in the summer. (6) The long term analysis of topography variations in the vicinity of Shuitou Harbor showed that there is a balance of deposition and erosion. The depositions in the northern part of the study area during the northeast monsoon were eroded and moved north during the period of southwest monsoon. On the other hand, in the southern area, the erosions during the winter were supplied by northward sediment movement in summer. In the long term, the seabed terrain of Shuitou Harbor has no significant change.
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