Erosion caused by hyperconcentrated flow on the Loess Plateau of China

Abstract

Hyperconcentrated flows are widely observed in the middle Yellow River basin. They occur as a result of erosion, but once they form on slopes, they operate as a strong eroding and sediment-carrying force and play an important role in drainage basin erosion and sediment production processes. Since the energy expenditure is less and sediment-carrying capacity is greater, hyperconcentrated flows have very high eroding and transporting abilities. There exists a strong coupling relation between hyperconcentrated flow transport and gravitational erosion, which ensures a rapid removal of mass-wasted materials. Hyperconcentrated flows are an important factor responsible for the high-intensity erosion and sediment yield in the middle Yellow River basin. Many previous studies have indicated that the sediment delivery ratio on the Loess Plateau approaches 1. This can be explained by the action of hyperconcentrated flows. As hyperconcentrated flows exhibit some particular behaviors in erosion and sediment production processes, the present study suggests that the erosion by hyperconcentrated flows be regarded as a special type of erosion. Accordingly, some countermeasures are proposed to control hyperconcentrated flows and the resulting erosion.