Assessing riverbank collapse with lateral displacement of shoreline for ecologically friendly erosion-resistant solutions

Many alluvial rivers worldwide are plagued with significant geomorphology changes due to severe riverbank collapse. This study developed an approach for quantifying riverbank erosion and outlined a structure for riverbank preservation based on insights gained from field investigations conducted in the lower Yellow River. Using the erosional forces, the newly introduced assessment method enables convenient measurement of riverbank erosion at various locations, even without cross-sectional profiles or channel-specific data. Abundant evidence highlights the severe riverbank collapses in the lower Yellow River, exemplified in the Jiyang Reach, where the left riverbank retreated at 26.0 m/yr from March 31, 2016 to May 10, 2018. The presence of weak soil erosion resistance is an inherent cause of riverbank collapse, with the critical shear stress of the soil being only 0.1 N/m 2 , significantly lower than that of the flow of 3.1 N/m 2 . Climate change and human activities, such as increased heavy rainfall frequency, reduced incoming water-sediment conditions and changes in riverbank boundary conditions, have triggered riverbank collapse. To prevent the occurrence of riverbank collapse, this study proposes a theoretical framework for a riverbank protection structure that simultaneously addresses the need for flood control and ecological conservation.