中文摘要：

岛屿海岸所处的水动力泥沙环境以及工程实施后引起的相关变化都具有自身的独特性和复杂性。根据历史资料，在对嵊泗中心渔港海区已建工程影响下的水沙动力过程变化深入分析的基础上，利用波浪和潮流共同作用下的二维泥沙数学模型，对拟建工程引起的潮流场、含沙量场以及海床冲淤变化进行了分析和预测。研究表明，已建与拟建防波堤工程会引起港区水动力减弱，海床演变以淤积作用为主，年淤积强度0．1—0．3m；已围与拟围海造地工程则会柬窄潮流通道，导致水动力增强，海床以轻微冲刷为主。拟建工程与已建工程作用下的水沙动力过程具有良好的类比性。

英文摘要：

The hydrodynamic and sediment environments near island coasts and its changes caused by coastal structures both have their own characteristics and complexity. According to the historic data, the changes of the process of hydrodynamics and sediment in the Shengsi fishery port area, caused by the builting coastal structures, are analyzed systematically. On the basis above a 2D mathematical model for sediment transport by waves and tidal currents is developed, and the changes of the tidal current field, sediment concentration field and the deposition-erosion caused by the proposed coastal structures are predicted and analyzed by the model. After the implement of the built and the proposed breakwaters in the fishery port area, the hydrodynamic conditions are worse obviously and the seabed is deposited with a rate of 0.1 - 0.3 m per year. After the implement of the built and the proposed reclamation in the fishery port area, the hydrodynamic conditions are better and the seabed is eroded slightly. The effects on the hydrodynamic and sediment environments caused by both the built and the proposed coastal structures have a good consistency.