HELD SURVEY OF SEDIMENTS IN THE MIDDLE REACH OF THE YELLOW RIVER AND EXPERIMENTS OF HYPERCONCENTRATED FLOW IN AN OPEN CHANNEL

The Yellow River basin has serious problems of flood and irrigation due to hyperconcentrated flow from the tributaries of its middle reach. In order to solve these problems, it is important to estimate sediment transport and bed variation in the rivers. The Kuye and Dali River are selected as the study area. First, we investigated sediment characteristics in the Kuye and Dali River. It is found that the Kuye River bed sediment is silt to coarse sand and the Dali River bed sediment is silt to very fine sand. Second, we made experiments of hyperconcentrated flow in an open channel, using silt or sand as flowing materials. It is found that hyperconcentrated flow behavior becomes quite different with grain size and concentration.