2023 Volume 79 Issue 17 Article ID: 23-17100
In Hishinuma area of the Chigasaki coast, beach nourishment was adopted as a measure against beach erosion and the recovery of sandy beach is now in progress. In this area, detailed beach survey has not been carried out, and the lack of basic data caused the difficulty in understanding the mechanism of beach changes. Therefore, on 25 April 2022 and 22 November 2022, beach survey using a UAV was carried out in this area. Moreover, the Narrow Multi-Beam (NMB) surveys were also conducted in January in 2022 and 2023. Using these survey data, the topographic changes of the area were investigated. During the field observation, waves were incident from the easterly direction, being the reversed direction against the normal wave direction, causing westward longshore sand transport. Faithfully given the observed wave intensity and wave direction, the reproduction calculation of the beach topography was carried out. Measured topographic changes were well reproduced by the calculation using the BG model.
