Investigation on the sedimentation relation between the upper and lower reaches from the flow-sediment combination in the lower Yellow River

The paper summarized previous researches on the relation of channel formation between the upper and the lower reaches in the lower Yellow River from flow/sediment conditions, analyzed statistically the hydrological data of 422 floods from 1960 to 1999 and set up sediment transport equations for the upper and the lower river reaches. Then the critical conditions between scour and siltation for the upper and the lower river reaches are derived as a function of flow discharge and sediment concentration as shown in Fig.7, which indicates that the river channel would be scoured when flow is relatively clear, and filled when flow is relatively muddy. The upper and the lower reaches of the lower Yellow River would be scoured/silted simultaneously when the flow is badly unsaturated with sediment, the upper reach would be scoured and the lower reach would be silted when the inflow is relatively clear, the upper reach would be silted and the lower reach would be scoured when the inflow is relatively muddy.