Downslope erosion response of engineered landform to upslope runoff in loess hilly region

In order to figure out the quantitative influence on wash-scour erosion at the bottom of high and steep slope of engineered landform caused by upslope runoff, the typical abrupt slope (36°) of engineering deposits along the expressway from Shenmu to Fugu was selected in the research to conduct a set of field runoff scouring experiments. Given that total runoff amount was kept constant, four types of upslope runoff were designed to conduct the subsequent analysis of the downslope runoff erosion response and sediment transport process on the abandoned spoil-deposit. The results indicated that: ① The type of upslope runoff had little influence on total surface runoff production at the bottom of the deposit slope, but it interfered the process of slope erosion and sediment yield, which increased the amount of soil loss; ② All the indicators of runoff depth, unit runoff erosivity, and stream power can well predict the intra-event sediment delivery modulus at the bottom of deposits slope induced by individual variable upslope runoff events; ③ The unit runoff erosivity based on flow discharge per unit width and runoff depth, can be used as the index to represent the change of runoff erosion power in single upslope runoff events, regardless of the type of upslope runoff. The results can be helpful in evaluating the intensity and degree of soil erosion, establishing erosion model in dramatically disturbed areas, and preventing from newly-arising water and soil losses against engineered landforms.