STUDY ON THE APPLICABILITY OF DAM SEDIMENT TOPOGRAPHY MEASUREMENT BY GREEN LASER AND SIMULATION OF FLUSHING

Abstract

 This study reports on the applicability of the UAV green laser, which can simultaneously measure land and sub-surface areas, to the measurement of dam sediment topography and the utilization of the 3D data obtained. The study targets three hydroelectric dams where sedimentation has been progressing in recent years. The main results of the study showed that (1) the acquisition rate of 3D point cloud data is generally more than 85% of the measurement area, (2) the measurement accuracy error satisfied the required accuracy, and (3) in areas where there was a possibility of missing measurements, it was effective to operate the reservoir level up or down according to the measurement method, and the combined use of narrow multibeam and green laser is effective. Furthermore, a detailed topographic mesh was created from the high-density three-dimensional point cloud data acquired by the green laser, and a reproducible simulation of flushing sand discharge was performed to construct an analytical model that can be used to predict sand discharge in the future. In conclusion, this study demonstrates the applicability of the UAV green laser to the measurement of dam sedimentation and the usefulness of the acquired data.