Influence of Water Exchange in Tide and Wave for Large Harbor with One Entrance

For the large coastal harbor with one entrance attacked badly from the waves and sands from the sea, it is advantaged to break waves and produce sands, but not advantaged for the water exchange flux, especially when a point source appearing inside the harbor, the polluted water is difficult to flow into the sea in time and be diluted by the water from outside. The water flow in estuary presents the character of to-and-fro flow, and the polluted source will flow into harbor with the flood tide and pollute the harbor secondly, although it has been outside the harbor at least with the ebb tide. For the harbor with one entrance against waves, the polluted source will be more difficult to be transported to the outside when waves coming, and the water environment capacitance will decline rapidly for the polluted water not to be absorbed. It is Taizhou Wenling harbor for example in Zhejiang province, and the movement of water particle is simulated in tidal current and wave to describe the movement of the point source transported not diffused. The rusults show that the capacity of water exchange for the large harbor wih one entrance will be declined in both tidal current and wave.