ABSTRACT
The Shibetsu River in the northeastern part of Japan is the site of a project to reconnect previous meanders that have become oxbow lakes to the current river channel. The two-way channel method was adopted for this project. It allows straightened parts and previous meanders to co-exist, thus restoring the rich natural environment that was lost when the channel was straightened, while allowing flood water to flow safely. A variety of surveys of the test site profiles were conducted on site over seven years. In this study, the discharge ratio of a two-way channel was considered, focusing on channel bed deformation. Measurement data were also verified using non-uniform flow calculations. The water levels of meandering and straight parts were calculated. The flow distribution ratio was found to be estimable based on the difference in cross-sectional areas of flow at the diverging points.
