FUNCTIONAL EVALUATION OF FULL-WIDTH ROCK-RAMP FISH PASSAGE USING FLOW TRACERS AND DRONES

Abstract

 In small and medium-sized rivers, the installation of scaled full-section fishways, in which large and small pools are placed at various drop-offs, has been increasing. However, a clear method for design and functional evaluation of the scaled fishway has not been established. In this study, we conducted a field survey using floats and a UAV to understand the function of the installed scaled fishway. The same survey was also conducted for the terraced fishway to compare its function with that of the scales type. From the survey data, we analyzed 1) the dispersion and flow time of the floats, 2) the drop between pools and the movement path of the floats from the 3D point cloud data of the fishway, and 3) the flow angle of the water vein and the pool shape. As a result, the characteristics of the scaly fishway were clarified, for example, the larger the dispersion of the floats, the more diverse the fish migration path.