Response mechanism of ice floods to scour and silting evolution in the Inner Mongolian channel and reaches of the Upper Yellow River

The alluvial river flooding problem in Inner Mongolia is prominent along the upper reaches of the Yellow River. Studying the scour and silting evolution of the river and the response mechanism of the floods can provide technical support for flood prevention and disaster mitigation in this river section. According to data on ice flood and scour and silting evolution, this paper produces the response relationship between a scour and silting evolution characteristics indicator and an ice flood condition change representation indicator based on formulaic calculations and related analyses. The results show that bankfull discharge, a characteristic indicator of river scour and siltation evolution, is closely related to the characterization indicators for ice flood sub-ice flow capacity and trough water storage increment. The under-ice flow capacity is about 1/5 that of bankfull discharge, and it decreases as bankfull discharge decreases. In addition, the channel detention increment increases as bankfull discharge decreases. The safety flow capacity in the main channel for ice flood control should not be less than 2 000 m³/s, and the increment in water storage should be kept below 1.4 billion m³ in the reach. The preliminary results can serve as a major guide for ice flood control in Inner Mongolian reaches.