Abstract
The effect of artificial flood on river channel disturbance is clarified quantitatively using the results of field observations and numerical simulations. Based on the prediction of positive impacts expected in the maintenance of ancient watercourses, channel changes were analyzed using river bed calculations during the flood of August 2016, which was the largest available scale. Results showed that the vegetative area lost owing to the flood tended to be larger along the old watercourse than they were in the current channel, and was also noticeable in the section where the old watercourse was actively maintained by excavation. This research has demonstrated that the maintenance of the old watercourse has positive impact on the restoration of gravel bars by promoting channel changes during floods.
