Abstract
Woody debris flow causes various damage at the time of a flood. One of the causes of river channel blockade, dropped bridge and a fishing net damage is the woody debris flow. Based on the results of past research, it is considered that the woody debris behavior is correlated to the bars. In this study, we investigated detail relationship of development in the bars and the woody debris behavior such as their generation, re-movement and accumulation. For tracking the woody debris behavior, we tagged numbered tape to each piece of woody debris found along two selected rivers where the development situation of their bars was different. As a result, we confirmed the great correlation of the numbers of the woody debris per unit distance and the area of the bar at the rivers where bars develop. Thus, after a small scale rain event, the accumulated woody debris re-moved and then it re-accumulated again in a bar around the water's edge with the high submergence frequency. Therefore, we conclude that a bar has the effect which catches woody debris.
