BEACH CHANGES ASSOCIATED WITH DEVELOPMENT OF A SAND SPIT AT HARAI RIVER MOUTH IN YUKUHASHI CITY

Abstract

 In 2012, a groin with a low crown height was constructed together with beach nourishment at the Harai River mouth on the Kutsuo coast. After the construction of a groin, longshore sand transport toward the mouth was blocked by the groin, resulting in severe beach erosion at the river mouth bar on the left bank of the river, which had been extending for a long time. At Kutsuo fishing port on the right bank of the river, the deposition of sand which was originary transported offshore by the river currents and then transported by waves continued, resulting in the deposition of the navigation channel. The beach changes around the Harai River mouth was investigated using satellite images and field observation was carried out. Finally, the results were compared with the results of the movable-bed experiment.