Quantifying the mechanical and hydrologic effects of riparian vegetation on streambank stability
Quantifying the mechanical and hydrologic effects of riparian vegetation on streambank stability
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DOI：
10.1002/esp.325
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发表时间：
2002-05
影响因子：
3.3
通讯作者：
A. Simon;A. Collison
中科院分区：
文献类型：
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作者：
A. Simon;A. Collison
河岸植被带被河流管理者广泛用于增加河岸稳定性等目的。然而，虽然植被对河岸稳定性的影响被广泛讨论，但很少量化，而且通常低估了水文过程的重要性，其中一些可能是有害的。本文介绍了一项实验的结果，在该实验中，四种河岸树种和两种侵蚀控制草的水文和机械效应与河岸稳定性的关系被量化。使用三种河岸覆盖物（成熟树木、丛生草和裸露/修剪的草坪草）下河岸地块的岩土和孔隙水压力数据来驱动ARS河岸稳定性模型，并将所得安全系数（Fs）分解为其组成部分，以评估单个水文和机械效应（土壤水分改良、根系加固和超载）的贡献（有益或有害）。树木根系可使土壤强度增加2-8 kPa，这取决于物种，而草根则可使土壤强度增加6-18 kPa。边坡稳定性分析的基础上收集的数据在2000年春季银行故障（后一个非常干燥的前期）表明，树木覆盖的机械效应增加Fs的32%，而水文效应增加Fs的71%.For草的数字是70%的机械效应和减少Fs的10%的水文效应。然而，基于2001年春季（在一个比平均前期更潮湿的时期之后）的河岸崩塌的分析表明，树木覆盖的机械效应使Fs增加了46%，而水文效应增加了29%，对于草，这两个数字分别为49%和-15%。在2001年春季的几个时期，树木覆盖的水文效应降低了河岸的稳定性，尽管这总是被稳定的机械效应所抵消。结果表明，水文过程中控制河岸稳定性的重要性，并强调需要选择河岸植被水文以及机械和生态标准的基础上。出版社：John Wiley & Sons，Ltd.
Riparian vegetation strips are widely used by river managers to increase streambank stability, among other purposes. However, though the effects of vegetation on bank stability are widely discussed they are rarely quantified, and generally underemphasize the importance of hydrologic processes, some of which may be detrimental. This paper presents results from an experiment in which the hydrologic and mechanical effects of four riparian tree species and two erosion‐control grasses were quantified in relation to bank stability. Geotechnical and pore‐water pressure data from streambank plots under three riparian covers (mature trees, clump grasses and bare/cropped turf grass) were used to drive the ARS bank stability model, and the resulting factor of safety (Fs) was broken down into its constituent parts to assess the contribution (beneficial or detrimental) of individual hydrologic and mechanical effects (soil moisture modification, root reinforcement and surcharge). Tree roots were found to increase soil strength by 2–8 kPa depending on species, while grass roots contributed 6–18 kPa. Slope stability analysis based on data collected during bank failures in spring 2000 (following a very dry antecedent period) shows that the mechanical effects of the tree cover increased Fs by 32 per cent, while the hydrologic effects increased Fs by 71 per cent. For grasses the figures were 70 per cent for mechanical effects and a reduction of Fs by 10 per cent for the hydrologic effects. However, analysis based on bank failures in spring 2001 (following a wetter than average antecedent period) showed the mechanical effects of the tree cover to increase Fs by 46 per cent, while hydrologic effects added 29 per cent. For grasses the figures were 49 per cent and −15 per cent respectively. During several periods in spring 2001 the hydrologic effects of the tree cover reduced bank stability, though this was always offset by the stabilizing mechanical effects. The results demonstrate the importance of hydrologic processes in controlling streambank stability, and highlight the need to select riparian vegetation based on hydrologic as well as mechanical and ecological criteria. Published in 2002 by John Wiley & Sons, Ltd.