Runoff and Sediment Yield on Very Steep Slopes under Simulated Rainfall
Soil erosion is one of the most important factors that lead to soil degradation. Many studies have been conducted the effects of slope steepness on soil erosion. Some of these studies showed that there is a unique slope named critical slope of erosion, at which maximum soil loss occurred. When slope steepness was different than that unique slope, soil loss was less. Most of these relationships were developed using data collected on slope up to approximately 35°. In this study, soil loss data within slope ranged from 25° to 45 ° were used to access the effect of very steep slope on soil erosion. The results indicated that the volume of runoff and flow velocity decreased with increasing slope gradient. Along with runoff and flow velocity decreasing, flow Reynolds number and Froude number decreased from about 19 to 13 and from 0.00055 to 0.00009, respectively, while Darcy-Weisbach friction coefficient increased from 3.27 to 4.29. There were two critical slopes of soil erosion within the given slope scope. The first critical slope emerged between 25～35°, at which maximum soil loss occurred; the second critical slope emerged between 30～40°, at which minimum soil loss occurred. The probable reasons for that were that the main form of rainfall erosion changed from runoff erosion to splash erosion with increasing slope gradient due to the changing hydraulic characteristics.
soil erosion very steep slope critical slope gradient of erosion
Xiao-wu He Feng-ying Li
College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang, 330045, China;The State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation,Chinese Academy of Science and Ministry of Water Resources, Yangling, 712100, China
国际会议
西安
英文
998-1001
2010-10-11（万方平台首次上网日期，不代表论文的发表时间）