PROCUREMENT OF MATERIAL FOR BEACH NOURISHMENT FROM CUSPATE FORELAND BEHIND DETACHED BREKWATER - FIELD EXPERIMENT IN ARAMATA AREA ON SHIMONI-IKAWA COAST

Abstract

 On the Shimoni-ikawa coast, the procurement of sand for beach nourishment is required at present. A large amount of sand is excessively deposited around No. 1 detached breakwater in Aramata area, causing the discharge of sand into the deep sea. Therefore, if the beach material excessively deposited around No. 1 detached breakwater is excavated for the procurement of beach nourishment sand, it may be effective for preventing sand from discharging into the deep sea. To investigate this method, the excavation of the cuspate foreland behind the detached breakwater was started since May 2017, and excavated material was transported downcoast. In this study, bathymetric survey data, photographs by UAV (drone), and CCTV imageries were analyzed along with the analysis of data set of wave observation. The redeposition process of sand behind the detached breakwater was investigated.