2019 Volume 75 Issue 2 Pages I_115-I_120
On National Route No. 232 along Rumoi coast in Hokkaido, the wave overtopping leads damaged along coast by the strong west wind. The ridgeline and shallow water survey are conducted at the damaged area as a countermeasure. This area is very challenging for surveyor because there are shallow reef zoon around 300m offshore and extensively developed bar around surf zone. Therefore, Airborne LiDAR Bathymetry(ALB) method was utilized for the survey. In this survey, ALB was able to detect maximum depth of 10m and the topography was well detected such as bar at water depth 3m and rocks above water distributed shallow area. In comparison with the prior survey method, the ALB are effective for shallow water survey: position accuracy was achieved within 15cm, and field and analysis work time are 2.3 times efficient, cost effective when the survey track lines are over 2.1km, aerial photos can be collected simultaneously.
