Loess Hill Slope Erosion and Sediment Yield Process Using A Dual Box System

Xiao Peiqing Zheng Fenli Jia Yuanyuan ( State Key Laboratory of Soil Erosion and Dryland Fanning on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resourcse, 712100 Yangling, Shaanxi; Scientific Institute of Hydraulic Research of Yellow River, Yellow River Conservancy Commission, 450003 Zhengzhou: China)

dual-box system; run-on water and sediment; net sediment delivery; erosion process

To quantify mutual influences and mechanisms of erosion processes about different erosion zones on loess ridge -mound-slope, which will provide important theoretic basis for constructing slope erosion prediction model. So a dual-box system of feeder box and test box with 15?gradient and clay loess was used to quantify effects of runoff and sediment from up-slope on down-slope erosion process under different sediment concentrations in up-slope runoff, rainfall intensities and soil surface conditions. The experiment results showed that runoff and sediment from up-slope have significant impacts on down-slope erosion process,sediment from up-slope was wholly transported, and runoff in up-slope caused the net sediment delivery ( S ) , sediment regime at down-slope is erosion-transported dominated. For the loose and compact surface treatments, the net sediment delivery ( S ) caused by up-slope runoff accounts for the total sediment delivery ( Sft) at sown-slope 31.7% to 97.3% and 45.1% to 89.7% separately. The net sediment delivery (S) increases with an increase of rainfall intensity. In addition, soil bulk density and rill erosion development have great effects on the sediment delivery ( s) . Soil bulk density affects soil erosion process and the sediment delivery ( s) during the run is associated with rill head-cut advance.