Effects of up-slope runoff and sediment on ephemeral gully erosion sediment and hydraulic parameters
上方来水来沙对浅沟侵蚀产沙及水动力参数的影响

The ephemeral gully erosion was an important issue and had great distribution in the Loess Plateau. The runoff and sediment from up-slope had great impacts on slope soil erosion. In this paper, its effect on down-slope ephemeral gully erosion sediment yield and hydrodynamic parameters were analyzed by water discharge scouring experiments in fields, with the designed discharge 5L/min,10L/min and 15L/min on the slope of 26°. The results indicated that the runoff from up-slope increased the flow velocity. The Reynolds number, Froude number, stream power and shearing force increased by 33%-76%, 21%-47%, 29%-72%, 18%-42% respectively, and the Daycy-Weisbach coefficient decreased by 11%-13%, which caused the increasing sediment of the ephemeral gully erosion. Except the flow velocity and Froude number, the other hydrodynamic parameters increased over the water discharge scouring time. There was a power relationship between ephemeral gully relative increment sediment yield caused by up-slope runoff and relative increment of the stream power and shearing force.