| 黄土丘陵沟壑区细沟发育形态的变化及其与侵蚀产沙的关系 |
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| 引用本文： | 李朋飞,黄珂瑶,胡晋飞,高健健,郝铭揆,党恬敏,张晓晨.黄土丘陵沟壑区细沟发育形态的变化及其与侵蚀产沙的关系[J].农业工程学报,2022,38(18):92-102. |
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| 作者姓名： | 李朋飞 黄珂瑶 胡晋飞 高健健 郝铭揆 党恬敏 张晓晨 |
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| 作者单位： | 1. 西安科技大学测绘科学与技术学院，西安 710054；;2. 黄河水利委员会绥德水土保持科学试验站，榆林 719000；;3. 黄河流域水土保持生态环境监测中心，西安 710021 |
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| 摘 要： | 细沟发育及形态特征研究对理解坡面侵蚀过程和机理具有重要意义。然而，已有细沟侵蚀研究多基于室内模拟试验，无法反映野外真实细沟侵蚀规律。该研究以黄土丘陵沟壑区辛店沟流域为例，于野外自然坡面设置5个径流小区，结合放水冲刷试验（流量为25、40、55、70、85 L/min）与地基三维激光扫描技术，研究细沟几何形态（长、断面宽、断面深），衍生特征（细沟宽深比、细沟密度、细沟割裂度和细沟平均深度等）和分形维数、地貌信息熵、分叉比的变化过程，以及不同指标与侵蚀量、沉积量、产沙量间的关系。结果表明：1）随着冲刷时间增加，各流量梯度细沟断面宽度、断面深度、细沟平均深度和细沟割裂度均呈递增趋势。而细沟宽深比与流量大小相关，低流量（25 L/min）下细沟发育主要呈"宽浅式"，较低流量（40 L/min）和高流量（85 L/min）下发育主要呈"窄深式"，中流量（55 L/min）和较高流量（70 L/min）细沟发育在"宽浅式"与"窄深式"间交替变化。2）随着冲刷时间增加，低流量下分形维数整体趋于平稳，其余流量波动较大；中流量下分叉比呈上升趋势，其余流量下均呈下降趋势；各流量梯度下地貌信息熵无明显变化规律，但其与产沙量的变化趋势基本一致，能够较好反映土壤侵蚀的动态变化。3）细沟平均长度、平均断面深度和细沟平均深度可分别用于评估较低流量下累计沉积量、侵蚀量和产沙量；同时，可用细沟平均深度评估低流量下累计侵蚀量和产沙量。平均断面宽度、平均断面深度及细沟平均深度可用于评估较高流量下累计侵蚀量。此外，随着流量的增大，各形态指标与累计侵蚀量、沉积量和产沙量关系的显著性减弱。研究可为深化认识坡面细沟侵蚀过程和机理提供参考。
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| 关 键 词： | 侵蚀 坡面 产沙 黄土丘陵沟壑区 野外放水冲刷 细沟 形态 TLS |
| 收稿时间： | 2022/8/10 0:00:00 |
| 修稿时间： | 2022/8/10 0:00:00 |
Morphological development of rills and its relationship with hillslope erosion in the hilly and gully Loess Plateau |
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| Li Pengfei,Huang Keyao,Hu Jinfei,Gao Jianjian,Hao Mingkui,Dang Tianmin,Zhang Xiaochen.Morphological development of rills and its relationship with hillslope erosion in the hilly and gully Loess Plateau[J].Transactions of the Chinese Society of Agricultural Engineering,2022,38(18):92-102. |
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| Authors: | Li Pengfei Huang Keyao Hu Jinfei Gao Jianjian Hao Mingkui Dang Tianmin Zhang Xiaochen |
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| Institution: | 1. College of Geomatics, Xi''an University of Science and Technology, Xi''an 710054, China;;2. Suide Test Station of Soil and Water Conservation, Yellow River Conservancy Committee of Ministry of Water Resources, Yulin 719000, China;;3. Yellow River Basin Monitoring Center of Water-Soil Conservation and Eco-Environment, Xi''an 712100, China |
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| Abstract: | Abstract: Rill erosion has been widely recognized as one of the most important forms of soil erosion on hillslopes. A crucial impact of rill erosion can be also posed on other erosion processes in downslope areas (e.g. gully head retreat). Morphological parameters of rills can provide useful indicators for the initiation and development of rill erosion. Previous studies have investigated the rill morphology in the erosion-deposition processes of hillslopes. However, those experiments were mainly taken in the laboratory. The physiochemical properties of backfill soil used in laboratory experiments are rather different from those of the natural soil in the field. The representative experiments were largely confined to the field erosion processes. It is necessary to explore the rill morphology associated with the erosion processes in the field. In this study, a series of field scouring experiments were conducted to determine the morphological development of rills under the hillslope erosion in the hilly and gully Loess Plateau. Five erosion plots were established on a natural slope of a small catchment (i.e. Xindiangou catchment), particularly with the input flow of hillslopes of 25, 40, 55, 70, and 85 L/min. Terrestrial Laser Scanning (TLS) was employed to acquire the ultra-high terrain information prior to the test. The various morphological parameters of rills were then derived, including the geometric indicators (length, width, and depth of cross sections), derived indicators (the ratio of width to depth, rill density, rill cleavage, and average rill depth), fractal dimension, bifurcation ratio, and geomorphic information entropy. A systematic investigation was also made to determine the effects of indicative morphological parameters on the cumulative erosion and deposition mass, as well as the sediment yield in the hillslope erosion. Results showed that: 1) The width and depth of the cross-sectional rills, the average rill depth and rill cleavage increased as the experiment progressed under all the flow conditions. The width-depth ratio was greatly varied in the input flow rate. The rills were primarily wide and shallow under the low flow condition (25 L/min), while narrow and deep under the moderately low (40 L/min) and high flow (85 L/min) conditions. There was a great change between the narrow-deep and wide-shallow manner under the moderate (55 L/min) and moderately-high (70 L/min) flow conditions. 2) The fractal dimension of rills was found to change slightly under the low flow condition, whereas, there was a considerable change under the rest of the input flow condition. The bifurcation ratio of rills increased under the moderate flow condition, while decreasing under the rest flow condition. Furthermore, the geomorphic information entropy varied significantly under the different flow conditions. However, there was the same change trend of geomorphological information entropy and sediment yield, indicating the dynamic changes of soil erosion. 3) The average rill length, the average depth of cross sections, and the derived average rill depth served as better indicators for the cumulative deposition mass, erosion mass, and sediment yield under the moderately low flow condition. The derived average rill depth was also for the cumulative erosion mass and cumulative sediment yield under the low flow condition. The average width of cross sections, average depth of cross sections, and derived average rill depth better indicated the cumulative erosion mass under the moderately high flow condition. In addition, there was a less significant relationship between the rill morphological parameters and cumulative erosion mass, deposition mass, and sediment yield, as the input flow increased. The finding can provide a strong reference to enhance the current understanding of the processes and mechanisms of hillslope erosion. |
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| Keywords: | erosion slope sediments hilly and gully Loess Plateau field scouring experiments rills morphology TLS |
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