EROSION OF RYUYO COAST DUE TO LONGSHORE SAND TRANSPORT REVERSED FROM NORMAL CONDITION

Abstract

 During T1919 landed Shizuoka Prefecture on October 12, 2019, severe beach erosion occurred east of No. 6 detached breakwater on the Ryuyo coast. Due to the past history of beach erosion on this coast, beach erosion seemed to be caused by eastward longshore sand transport. When analyzing the change in longitudinal profiles along transects at 200 m intervals alongshore, it was found that westward longshore sand transport reversed from the normal condition occurred because of oblique wave incidence from counterclockwise direction relative to the direction normal to the shoreline. The beach changes due to this longshore sand transport were analyzed.