2022 Volume 78 Issue 2 Pages I_745-I_750
On the Niigata Port Coast (west coast), a costal erosion countermeasure by the integrated shore protection system was conducted in combination with submerged breakwater, jetty, and beach nourishment. The authors studied the measurement technique which enables them to understand the topographic status after the beach has been nourished in a rational and appropriate manner, while tentatively measuring the coastal landform using Airborne Laser Bathymetry (ALB). ALB can measure the depth from the sea surface up to 8 m below, which is the threshold depth of sediment movement of the relevant sea area. The average of the depth difference at the same point, which was measured by the traditional bathymetric and shoreline survey, was 0.14 m (absolute value), so ALB ensured the same level of accuracy as the former measurement. This result demonstrates the effectiveness of ALB as a monitoring technique to understand surface topographic changes of the relevant nourished beach on a large scale. In addition, as a result of pilot evaluations of beach width soundness, it was found to be able to confirm, in a single approach, the immobile points on both the sea and land sides as well as both the foreshore and backshore slopes, which are necessary for sandy-beach monitoring.
