Measuring flow velocity on frozen and non-frozen slopes of black soil through leading edge method

作     者：Chao Chen Yunyun Ban Xuefeng Wang Tingwu Lei 

作者机构：College of Water Resources and Civil EngineeringChina Agricultural UniversityQinghua DongluBeijing100083PR China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess PlateauInstitute of Soil and Water ConservationChinese Academy of Science and Ministry of Water ResourcesYanglingShaanxi Province 712100PR China 

出 版 物：《International Soil and Water Conservation Research》 (国际水土保持研究（英文）)

年 卷 期：2017年第5卷第3期

页      面：180-189页

核心收录：

学科分类：0710[理学-生物学] 09[农学] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境] 0815[工学-水利工程] 0901[农学-作物学] 0833[工学-城乡规划学] 0713[理学-生态学] 0834[工学-风景园林学（可授工学、农学学位）] 

基　　金：supported by the "National Nature Science Foundation" under Project 

主　　题：Flow velocity Leading edge method Frozen/non-frozen soil 

摘      要：Flow velocity is a major parameter related to hillslope hydrodynamics erosion.This study aims to measure flow velocity over frozen and non-frozen slopes through leading edge method before being calibrated with accurate flow velocity to determine the correct coefficient for convenience of flow velocity measurement.Laboratory experiments were conducted on frozen and non-frozen soil slopes with flumes involving four slope gradients of 5°,10°,15°,and 20°and three flow rates of 1,2,and 4 L/min with a flume of 6 m long and 0.1 m wide.The measurements were made with a stopwatch to record the time duration that the water flow ran over the rill segments of 2,4 and 6 m long.Accurate flow velocity was measured with electrolyte trace method,under pulse boundary condition.The leading edge and accurate flow velocities were used to determine the correction coefficient to convert the former to the latter.Results showed that the correction coefficient on frozen soil slope was 0.81 with a coefficient of determination(R2)of 0.99.The correction coefficient on non-frozen soil slope was 0.79 with R2 of 0.98.A coefficient of 0.8 was applicable to both soil surface conditions.The accurate velocities on the four frozen black soil slopes were approximately 30%,54%,71%,and 91%higher than those on non-frozen soil slopes.By contrast,the leading edge flow velocities on the frozen soil slopes were 23%,54%,67%,and 84%higher than those on non-frozen soil slopes.The flow velocities on frozen soil slopes increased with flow rate at all four slopes,but they increased from 5 to 15°before getting stabilized.Therefore,rill flow velocity can be effectively measured with leading edge method by multiplying the leading edge velocity with a correction coefficient of 0.80.This study provides a strategy to measure rill flow velocity for studies on soil erosion mechanisms.