Uav photogrammetry for topographic monitoring and river management system

Abstract

In this study, field works using a total station, 3D laser-scanner and photographic survey by UAVs (Unmanned Aerial Vehicles) were conducted in actual rivers for river management system in Gifu prefecture. To estimate the measurement error and enhance the precision of UAV, underwater topography information was considered. As a result, multiplex photograph by Photo scan pro was composed, and 3 dimensional coordinate calculated by using the stereo image of river topography information data. The possibility that UAV become the effective tool was shown by improving calibration of river information. Furthermore, the energy dissipating effect for multi-drop structures and food flow including the sediment into fish passage were estimated using by two-dimensional numerical model flow of UAV data. The results of analysis are considered from the energy gradient, Fronde number, turbulence intensity and other hydraulic quantities. As the decline of energy gradient and the sudden change of Froude number is indicated to hydraulic jump at multi-drop structures, it is clarified that the drop works is useful to large energy' dissipating efiect. In addition, on including sediment into the fish passage at the flood, the method of the maintenance is suggested according to such the procedure. Thus the river management under flood is realized by estimating the role ol function ot river structures.