Abstract
Characteristics of the flood flow, bed load and bed topography in compound rivers were investigated using laboratory tests and field data. Based on experimental resulting a series of non dimensional parameters were deduced to characterize flood flow. Plan shape features were showed by 14 Japanese compound rivers data analysis. Steady flow experiments were conducted in compound channels with different value of sinuosity and relative depth. As a result, for the case of bank full flow, maximum rate of bed load and scouring occurred caused by large secondary flow under plan shape conditions of bmc/Bm<0.5 and S<1.10. From unsteady experimental results with a given hydrograph, we have showed that the possibility of occurring inner bed scouring of main channel was very low due to the short duration of compound meandering channel flow. Finally, the classification diagram of the flood flow chacteristics (simple & compound meandering channel flow) in compound channels was presented in term of representative parameters such as sinuosity S and relative depth Dr, allowing the estimation of flood flow characteristics.
