Abstract
Distributions of river bed material are important to the bed variation as well as flood discharge and river plan form. The previous flume experimental studies have showed that the mechanism of bed variation in channels with sediment mixture is different from that of uniform sediment. But grain size distributions of the previous experiments are smaller than natural stony-bed rivers and gravel-bed rivers. In this study, we carried out field experiments by using compound straight-meandering channel in the Joganji river. And we compared the results of field experiments with the results of flume experiments. Furthermore, we performed the numerical analysis of the unsteady quasi-three-dimensional flow and bed variation in stony-bed channel and compared numerical computation results with field experimental results.