Calculation of Bed Variation by Debris Flows in The Mizunashi river on Mt. Unzendake

摘要

There have been debris flows on the slope of Mt. Unzendake since 1991. Sediment deposition from the debris flows causes significant increase of bed elevation in the downstream area of the Mizunashi River. From field observations the small-discharge debris flows can be regarded as sediment-laden flows with a high concentration of bed and suspended loads, whereas the large- discharge flows as typical debris flows.