Vol14 No.10: 2042-2052
【Title】Effects of simulated submerged and rigid vegetation and grain roughness on hydraulic resistance to simulated overland flow
【Author】YANG Ping-ping1; ZHANG Hui-lan1*; MA Chao
【Addresses】1 Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; 2 Jinyun Forest Ecosystem Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
【Citation】Yang PP, Zhang HL, Ma C (2017) Effects of simulated submerged and rigid vegetation and grain roughness on hydraulic resistance to simulated overland flow. Journal of Mountain Science 14(10). https://doi.org/10.1007/s11629-016-4280-0
【Abstract】Better understanding of the role of vegetation and soil on hydraulic resistance of overland flow requires quantitative partition of their interaction. In this paper, a total of 144 hydraulic flume experiments were carried out to investigate the hydraulic characteristics of overland flow. Results show that hydraulic resistance is negatively correlated with Reynolds number on non-simulated vegetated slopes, while positively on vegetated slopes. The law of composite resistance agrees with the dominant resistance, depending on simulated vegetation stem, surface roughness, and discharge. Surface roughness has greater influence on overland flow resistance than vegetation stem when unit discharge is lower than the low-limited critical discharge, while vegetation has a more obvious influence when unit discharge is higher than the upper-limited critical discharge. Combined effects of simulated vegetation and surface roughness are unequal to the sum of the individual effects through t-test, implying the limitation of using linear superposition principle in calculating overland flow resistances under combined effect of roughness elements.
【Keywords】Hydraulic resistance; Overland flow; Vegetation resistance; Grain resistance; Flume experiment