Abstract
Large-scale groins were constructed in the late 19th century in the downstream basin of the Kiso River. Riverside pools are formed between the groins, providing various ecological systems and favorable river environments. In this study, we analyzed configuration characteristics of scouring formed behind the large-scale groins of the Kiso River. We conducted field observations by setting up ADCP and other observation equipment downstream of the groins, and analyzed the downstream flow in relation to the scale of the flow, etc. through three-dimensional analysis. As a result, we found that a transverse vortex is formed downstream of the groin during flooding events, and that this vortex may have contributed to the generation of the downstream scouring.
