GEOMORPHIC APPROACH FOR MITIGATING IMPACT OF HARBOR CONSTRUCTION ON SANDY BEACHES

摘要

Some harbors constructed on sandy shore have interrupted littoral drift, resulting in updrift beach accretion, siltation in navigation channel, or downdrift erosion. Conventional harbor design procedures have focused on water tranquility in the basin and prevention of sediment into the harbor, using scaled hydraulic experiments or numerical modeling which could not precisely determine the effect of breakwater orientation and its tip on adjacent beaches. After having discussed a wide range of field cases of harbors in Japan, Korea, and Taiwan, this paper then demonstrates the potential of a quantitative approach based on the static bay beach concept for mitigating the impact of harbors on sandy beaches. With this alternative, the most preferred location of a breakwater tip to minimize the adverse effect on adjacent shorelines can be readily devised with a freeware MEPBAY on a computer screen. This approach could benefit the work of experimentalists and numerical modelers on planning a new harbor or improving an existing one in many countries.