Experimental study of fluvial processes in Inner Mongolia reach of Yellow River based on series of runoff-sediment conditions

In this study,five different series of annual runoff-sediment processes are designed and tested in laboratory settings to examine and simulate their accumulative effects on the fluvial processes in the Sanhuhekou-Zhaojunfen section of the Inner Mongolia reach of the Yellow River.A number of engineering control schemes for the fluvial process control are proposed,and it is found that the sedimentation in the main channel could be effectively mitigated if the scheme follows the main flow trend and the water potential in the channel;while the sedimentation under low flow rates could be significantly reduced since it is very unlikely to have the water diversion rate lower than 400m3/s.The results also indicate that the accumulative sedimentation from different fluvial process control schemes is positively correlated with tributary floods with high sediment content.The channel sedimentation increases with the frequency of the incoming tributary floods which also affects the evolution of the longitudinal profile of the study river section.When the low flow rate is dominant in the series of annual runoff-sediment process,the river hydraulic geometry B/H increases and the bankfull discharge decreases.It is also found that the incoming sediment coefficient S/Q during the flood season has a logarithmic correlation with B/H,and this implies that the runoff-sediment conditions during the flood season are crucial in the evolution of river section morphology.