2018 Volume 6 Issue 1 Pages 24-31
In the downstream tidal basin of the Kiso River, large-scale groins about 200 m long were constructed and a different river environment with pools and creeks was created by scouring, sedimentation, and foresting in intermediate areas of the groins. The scouring zone downstream of the large-scale groins played an important role in creating and maintaining an embayment water zone. In this study, we examined the scours that formed behind the large-scale groins in the Kiso River by field observations using acoustic Doppler current profiler (ADCP) and other observation equipment set downstream of the groins. The mechanism of creating downstream scour was then investigated by 2-D and 3-D numerical analyses in considering the effects of groins' lengths on the scouring. As a result, we found that offshore-heading streams occurred behind the groins during ebb tide and flood event, which may have caused the scouring downstream of the groins.
