Lateral variation properties in river channels due to bank failure along the desert valley reach of upper Yellow River

By means of field survey and measurement data analysis, the types of river bank erosion along the desert wide valley reach of the upper Yellow River can be classified into two types: cohesive bank and non-cohesive sand accumulation bank, according to the river bank material composition and the sediment source. The former type can be further classified into three subtypes: plane collapse, arc collapse and cantilever collapse, whereas the latter has two subtypes of erosion: surface sliding and plane collapse. Taking the Dengkou reach and the Wuhai reach for examples, and combining with remote sensing image interpretations for nearly 10 years, the shoreline variations are analyzed to reveal the lateral variation in the reaches due to bank failure. Results show that the bank collapse rate of cohesive bank erosion is greater than that of non cohesive sand accumulation bank erosion. In the short term, there appears to be formations of concave bank and accretion of convex bank in local bending channels, but in the long term, the whole reach tends to be in the overall trend of siltation. Therefore, the study has great significance to revealing the channel lateral deformation and the fluvial processes due to bank failure in the upper Yellow River.