The Influence of Short-Term Heavy Rainfall on Hydraulic Characteristics and Rill Formation in the Yuanmou Dry-Hot Valley

Jun Luo, Xueyang Ma (), Lei Wang, Bin Zhang, Xiao Yang and Tianxiang Yue
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Jun Luo: School of Geographical Sciences, China West Normal University, Nanchong 637009, China
Xueyang Ma: College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China
Lei Wang: School of Geographical Sciences, China West Normal University, Nanchong 637009, China
Bin Zhang: School of Geographical Sciences, China West Normal University, Nanchong 637009, China
Xiao Yang: School of Geographical Sciences, China West Normal University, Nanchong 637009, China
Tianxiang Yue: Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

IJERPH, 2022, vol. 19, issue 22, 1-21

Abstract: Rill erosion is one of the major environmental problems in the world; it is an important factor with regard to land degradation and has a serious impact on production and daily life in the region. The widely distributed Yuanmou group stratum promotes the development of rill erosion, whereby the strong time-concentrated rainfall and the alternating arid-humid climate prepare the ground for the development of rills in soils. Therefore, a study of the processes of slope rill erosion was carried out, and a gravel-soil slope in the Yuanmou dry-hot valley was chosen to simulate short-term heavy rainfall (25 mm/h) (No. 1 plot) and moderate rainfall (15 mm/h) (No. 2 plot), to study the erosion processes of soil and the dynamic characteristics of runoff involved in erosion. The study results showed that the width of runoff was significantly different between the two plots, while the depth of runoff was not significantly different. During the rill formation process, the width of the two plots first decreased and then increased with increasing washout duration, while its depth did not change significantly. Flow was the key factor in determining the hydraulic characteristics of runoff, and it had a significant or extremely significant positive correlation with hydraulic characteristics parameters, except in the case of Fr (Froude number) ( r = 0.039). The total sediment content (CS) of plot No. 1 (0.158 g/cm 3 ) was significantly different from that of plot No. 2 (0.153 g/cm 3 ), and both CSs in the two plots decreased with increasing washout duration. The CS had an extremely significant negative correlation with τ (runoff shear force) ( r = −0.863 **) and DW-f (Darcy-Weisbach drag coefficient) ( r = −0.863 **) and a significant negative correlation with Re (Reynolds number) ( r = −0.735 *) in the short-term heavy rainfall experiment, while the CS had a significant positive correlation with V (velocity) ( r = 0.814 *), R (hydraulic radius) ( r = 0.811 *) and P (unit stream power) ( r = 0.811 *) in the moderate rainfall experiment. The results of this study will help guide further examination of the processes involved in the dynamic mechanisms of rill erosion on slopes under short-term heavy rainfall conditions.

Keywords: washout duration; rill development; flow hydraulic characteristics; runoff development; short-term heavy rainfall (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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