STUDY ON CHANGES IN BED CONDITION AND FLOW RESISTANCE OF GRAVEL BED CAUSED BY SAND SUPPLY IN THE EXPERIMENTAL RIVER

Abstract

Changes in bed condition, flow resistance and sediment transport are discussed in gravel-cobble covered bed where sand is supplied artificially like as river reaches downstream of dam reservoirs, on the basis of experimental results obtained in a large scale flume called "the experimental river" in the Aqua Restoration Research Center, PWRI. Variations of the bed condition were clarified minutely by the use of a sophisticated system that enables automatic measurement of 1cm mesh intervals even under flowing conditions. Flow resistance and non-equilibrium process of sediment transport are confirmed to correspond closely to bed states under subcritical condition.