FORMATION OF ARTIFICIAL COAST AND LOSS OF COASTAL ECOSYSTEM DUE TO CONSTRUCTION OF SEAWALL IN MIYAKO ISLAND

On the Urasoko coast in Miyako island, gently sloping revetment was built with the land reclamation behind the revetment and the natural sandy beach was buried under the concrete wall. The aim of this construction work was to enhance recreational usage of the coast, but in reality its purpose was not sufficiently attained because of the disappearance of sandy beach. On the Uchihama coast in the same island, very beautiful natural seashore with low vegetations and many animals was altered to the gently sloping revetment, killing natural ecosystem. These situations were investigated by the field observations. Appropriate measure is proposed regarding the method to build seawall instead of the above-mentioned methods, if necessary.