Liu Ran, Yu Xin-Xiao, Cai Qiang-Guo, Sun Li-Ying, Fang Hai-Yan, Jia Guo-Dong, He Ji-Jun
School of Soil and Water Conservation, Beijing Forestry University/Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation, Beijing 100083, China.
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Ying Yong Sheng Tai Xue Bao. 2021 Aug;32(8):2886-2894. doi: 10.13287/j.1001-9332.202108.016.
Rainfall intensity, slope length, and slope gradient are the important factors affecting runoff and sediment yield. In order to quantitatively analyze the effects of rainfall intensity, slope length, and slope gradient on the erosion process of Ansai loess slope in loess hilly and gully region, we analyzed the variation of runoff and sediment yield on Ansai loess with two slope lengths (5, 10 m), three slopes (5°, 10°, 15°) and two rainfall intensities (60, 90 mm·h) in an indoor simulated rainfall experiment. The results showed that the initial runoff generation time decreased with the increases of slope length, though the overall change was not significant. The initial runoff generation time decreased with the increases of rainfall intensity. Compared with the intensity of 60 mm·h, the initial runoff generation time decreased by 5.7-18 min under the intensity of 90 mm·h. Among them, the runoff initiation time on the slope of 10° was the fastest. With the duration of rainfall, runoff yield rate increased rapidly at first, and then gradually fluctuated around a certain value. The sediment yield rate increased rapidly in a short period of time at the initial stage of runoff generation, and then decreased after reaching the maximum, and being gradua-lly stable. The rates of runoff and sediment yield increased with the increases of slope length and rainfall intensity, but the law of change with slope was not obvious. With the increases of rainfall intensity, slope length and gradient, the total sediment yield increased accordingly. Under the rainfall intensity of 90 mm·h, the slope surface with the length of 10 m and slope of 15° generated rill, leading to the highest total erosion amount (11885.66 g). Under the rainfall intensity of 60 mm·h, the erosion amount per unit area decreased with the increases of slope length, and there was a critical erosion slope length in 5-10 m slope section. Slope length, slope and rainfall intensity all played a promoting role in runoff process. Rainfall intensity, slope length, and their interaction contributed more to runoff yield rate and total erosion amount. Rainfall intensity contributed the most to runoff yield rate, with a contribution rate of 49.8%. The contribution rate of slope length to the total erosion was the largest, which reached 37.8%.
降雨强度、坡面长度和坡度是影响径流和产沙的重要因素。为定量分析降雨强度、坡面长度和坡度对黄土丘陵沟壑区安塞黄土坡面侵蚀过程的影响，在室内模拟降雨试验中，分析了安塞黄土在两种坡面长度（5米、10米）、三种坡度（5°、10°、15°）和两种降雨强度（60毫米·小时、90毫米·小时）条件下径流和产沙的变化情况。结果表明，初始产流时间随坡面长度增加而减小，不过总体变化不显著。初始产流时间随降雨强度增加而减小。与60毫米·小时强度相比，90毫米·小时强度下初始产流时间减少了5.7 - 18分钟。其中，10°坡面的产流起始时间最快。随着降雨历时，产流率起初迅速增加，然后在某一值附近逐渐波动。产沙率在径流产生初期短时间内迅速增加，达到最大值后减小，随后逐渐稳定。径流和产沙率随坡面长度和降雨强度增加而增加，但随坡度的变化规律不明显。随着降雨强度、坡面长度和坡度增加，总产沙量相应增加。在90毫米·小时降雨强度下，10米长、15°坡度的坡面产生细沟侵蚀，导致总侵蚀量最高（11885.66克）。在60毫米·小时降雨强度下，单位面积侵蚀量随坡面长度增加而减小，在5 - 10米坡面段存在临界侵蚀坡面长度。坡面长度、坡度和降雨强度对径流过程均起促进作用。降雨强度、坡面长度及其交互作用对产流率和总侵蚀量的贡献更大。降雨强度对产流率的贡献最大，贡献率为49.8%。坡面长度对总侵蚀的贡献率最大，达到37.8%。
