Research Progress on Causes and natural cut-off of distorted river bends

¹ Yellow River Institute of Hydraulic Research, Yellow River Conservancy Commission, Zhengzhou 450003, China ;
² North China University of Water Resources and Electric Power, Zhengzhou 450045, China ;
³ State Key Laboratory of Hydro-Science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China

^* Corresponding author: ehjiang@yrihr.com.cn

Abstract

In recent years, the distorted river bends occurs frequently in the lower reaches of the Yellow River, and the critical catastrophe occurs of natural cut-off under the action of flood scouring during flood season, which directly affects the plane shape of the river channel and the flood control safety of local reach. By collecting a large number of literature and combining existing research results, the causes of the deformed rivers and the natural cutting phenomenon are reviewed. The formation of the distorted river bends is mainly related to the incompatibility of the upstream water and sediment inflow conditions with the river boundary conditions, the formation of local anti-scour nodes (such as clay mouth) and the emergence or control engineering, and the different anti-scour properties of the riverbed leading to the main stream swing. In the development and evolution process of river bays, natural cutting curve occupies an important position, and there are three typical forms, such as erosion ditch type, bank collapsing type and die cutting type, and its cutting ratio is 1.6-6.9. In the future, we should study the composition of the river bed, study the causes and mechanism of the abnormal river regime in the lower Yellow River more deeply, predict the trend of the abnormal river regime scientifically, and evaluate the damage.