RAPID EROSION DURING TYPHOON NO. 19 IN 2019 AND BEACH RECOVERY ALONG SAGARA COAST

Abstract

 Beach changes in an event in which rapid beach erosion due to offshore sand transport under the storm wave conditions superimposed with the beach changes by longshore sand transport, and the recovery of the beach after the storm were investigated, taking the coast with a stretch of 16 km between Point Omaezaki and the Katsumata River in Suruga Bay as an example. It was found that although the beach was severely eroded by storm waves associated with Typhoon No. 19 that hit the area on 12 October 2019, sand returned to the shoreline by shoreward sand transport during the calm wave condition after the storm in Susuki area south of Sagara Port, where longshore sand transport is blocked by the Sagara Port breakwater. On the other hand, in the Sagara-Katahama area in northern part, both seaward sand transport and northward longshore sand transport occurred during the storm wave condition, and then the beach recovered due to shoreward sand transport under the calm wave condition and southward longshore sand transport.