HYDRAULIC EXPERIMENTS ON RIVER CHANNEL RESPONSE WHEN SLITTING A CHECK DAM

Abstract

 Check dams are extremely effective structures from the viewpoint of preventing sediment-related disasters. However, they cause discontinuities in riverbed longitudinal shapes and sediment transportation, and countermeasures are required from the viewpoint of river environment. In this study, hydraulic experiments based on the check dam of the Iwaubetsu River located on the Shiretoko Peninsula were conducted for examined the response of the river channel due to slitting of check dam. As a result, the continuity of the bed elevation is restored by the slitting of the dam, and in the case of small-scale flooding, the alternate sandbar shape before dam construction is regenerated. However, in subsequent large-scale floods, both the wavelength and wave height of the sandbars increase, although alternating sandbars are maintained.