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| DOI：10.13522/j.cnki.ggps.2019003 |
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| The Effects of Ryegrass Density on Hydraulic Resistance of Slope Against Overland Water Flow |
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ZHANG Lu, LIU Yuanbo, LEI Xiaozhang
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1. Power China Northwest Engineering Corporation Limited, Xi’an 710065, China;2. Sichuan University State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610065, China
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| Abstract: |
| 【Background】Reconstructing engineering projects to restore ecosystems functions has been in increase over the past few years, one issue in which is to restore vegetation coverage of slopes to reduce water and soil erosion.【Objective】The purpose of this paper is to experimentally study if and to what extent increasing planting density of ryegrass can improve hydraulic resistance of slopes against overland water flow and improve water infiltration.【Method】The experiment was conducted in laboratory. We measured and calculated the changes in water depth and hydraulic resistance of water flow over the slopes under different vegetation coverages.【Result】①Equations were derived to describe the spatiotemporal changes in water depth and total hydraulic resistance of water flow over the slopes. ②Rigid vegetation and flexible vegetation affected water flow in the slopes in different ways. The hydraulic resistance of the vegetation to water flow over the slope did not increase with the planting density monotonically; there was an optimal density which was most effective for the vegetation to hoard the water and slow down water flow.【Conclusion】Care should be taken in using vegetation to mitigate water and soil erosion from slopes in low mountainous and hilly areas. There was an optimal vegetation density which is most effective to slow waterflow over the slopes while in the meantime improve water infiltration. |
| Key words: soil and water conservation; overland flow; the density of vegetation; water depth; resistance |
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