Topographical Change in a Channel Bed after Habitat Improvement

Concrete blocks were removed in the winter of 1993 to 1994 for habitat improvement of aquatic animals in the bed of a concrete-lined reach of the Pankenai River, northern Hokkaido, Japan. Since the mudstone which lies under the concrete blocks is soft under water-saturated conditions, the channel bed was seriously eroded during a snowmelt season just after the improvement. This study reports the topography of the channel bed after the snowmelt.