Erosion and sediment yields as influenced by coupled eolian and fluvial processes: The Yellow River, China

Based on data from the middle Yellow River, a model of erosion and sediment yield is proposed to describe coupled eolian and fluvial processes in a transitional zone from arid to sub-humid climates, and to explain rapid erosion and a high sediment yield in the zone. In the study area, wind action predominates from March to June, which erodes weathered bedrock and transports eolian sand to gullies, river channels and floodplains. In the following summer, especially from July to September, rainstorm runoff in gullies and river channels transports large quantities of fine loessic material, in the form of hyperconcentrated flow. As a result, most of the previously stored eolian sand and material supplied by mass-wasting of loess can be transported to the major tributaries and the main stream of the Yellow River, resulting in the high specific sediment yield. There exists an optimal grain size composition which maximizes suspended sediment concentration in the study area, resulted from the combined wind–water processes.