Impacts of native vegetation on the hydraulic properties of the concentrated flows in bank gullies  

作　　者：SU Zheng-an HE Zhou-yao ZHOU Tao WANG Jun-jie WANG Xiao-yi WANG Li-juan FANG Hai-dong SHI Liang-tao LIU Yi-han WU Zuo 

机构地区：[1]Key Laboratory of Mountain Surface Processes and Ecological Regulation,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China [2]Forestry College,Sichuan Agricultural University,Chengdu 611130,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]College of Water Conservancy and Hydropower Engineering,Sichuan Agricultural University,Ya’an 625014,China [5]lnstitute of Tropical Eco-agricultural Sciences,Yunnan Academy of Agricultural Sciences,Yuanmou 651300,China [6]College of Geography and Resources Science,Sichuan Normal University,Chengdu 610101,China

出　　处：《Journal of Mountain Science》2021年第4期907-922,共16页山地科学学报（英文）

基　　金：supported by the National Key Research and Development Program of China(2017YFC0505102);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,No.2019QZKK0307);the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07101-001)。

摘　　要：To quantify the impacts of native vegetation on the spatial and temporal variations in hydraulic properties of bank gully concentrated flows,a series of in situ flume experiments in the bank gully were performed at the Yuanmou Gully Erosion and Collapse Experimental Station in the dry-hot valley region of the Jinsha River,Southwest China.This experiment involved upstream catchment areas withone-and two-year native grass(Heteropogon contortus)and bare land drained to bare gully headcuts,i.e.,Gullies 1,2 and 3.In Gully 4,Heteropogon contortus and Agave sisalana were planted in the upstream catchment area and gully bed,respectively.Among these experiments,the sediment concentration in runoff in Gully 3 was the highest and that in Gully 2 was the lowest,clearly indicating that the sediment concentration in runoff obviously decreased and the deposition of sediment obviously increased as the vegetation cover increased.The concentrated flows were turbulent in response to the flow discharge.The concentrated flows in the gully zones with native grass and bare land were sub-and supercritical,respectively.The flow rate and shear stress in Gully 3 upstream catchment area were highest among the four upstream catchment areas,while the flow rate and shear stress in the gully bed of Gully 4 were lowest among the four gully beds,indicating that native grass notably decreased the bank gully flow rate and shear stress.The Darcy–Weisbach friction factor(resistance f)and flow energy consumption in the gully bed of Gully 4 were notably higher than those in the other three gully beds,clearly indicating that native grass increased the bank gully surface resistance and flow energy consumption.The Reynolds number(Re),flow rate,shear stress,resistance f,and flow energy consumption in the gully beds and upstream areas increased over time,while the sediment concentration in runoff and Froude number(Fr)decreased.Overall,increasing vegetation cover in upstream catchment areas and downstream gully beds of the bank gully is essential for gully

关 键 词：Soil erosion Indigenous grass species Bank gully Concentrated flows Flow energyconsumption Dry and hot valley 

分 类 号：Q948[生物学—植物学]