RESPONSE CHARACTERISTICS OF GRAVEL BEACH FROM THE VIEWPOINT OF SHALLOW WATER WAVES AND MOVEMENT OF GRAVELS

Abstract

 The purpose of this study is to elucidate the process of massive erosion and the subsequent recovery of a gravel beach. Wave observation, topographic survey and monitoring of gravel migration were carried out during the typhoon season in 2019. The beach morphology and shoreline response were discussed in terms of wave characteristics in shallow waters with 4 m water depth, which is considered as the closure depth. Massive beach erosion was caused by the waves with about 4m height in the early stage of the typhoon, and the beach recovery was caused by waves from the north. The offshore wave height does not significantly affect the beach deformation if the wave height exceeds 3m – 4m.