Upland Controls on the Hydrological Functioning of Riparian Zones in Glacial Till Valleys of the Midwest 1
Upland Controls on the Hydrological Functioning of Riparian Zones in Glacial Till Valleys of the Midwest 1
复制标题
高地对中西部冰耕谷河岸带水文功能的控制 1
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
A. Smith
中科院分区：
文献类型：
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作者：
P. Vidon;A. Smith
摘要： 确定景观水文地质环境、河岸水文功能以及河岸区对气候和水质变化的敏感性之间的关系对于更好地利用河岸区作为未来的最佳管理实践至关重要。在这项研究中，我们研究了中西部深切冰碛谷河岸带的地下水位动态、水流路径以及降水、深层地下水 (DG) 和渗水作为水源的相对重要性。数据表明，地下水位波动受到土壤质地的强烈影响，并在较小程度上受到坡底附近产生渗漏的高地沉积物地层的影响。高地和河岸带 1.7-2m 处的耕作有助于保持该地点平行于地面的水流。该地点的高地地形陡峭（16%）和坡底附近的壤土，侧向地下水通量较小（<10 l/d/m 河流长度）且间歇性。尽管地形陡峭，坡底出现渗漏，但在夏季仍观察到水流路径从横向向谷底方向的转变。主成分和判别分析表明，全年河岸水与渗水最为相似，来自下耕单元埋藏砂砾层的 DG 并不是该地区河岸区域的主要水源。水质数据和河岸带补给对渗水的依赖表明，该环境中的地点可能对未来高地降水和水质的变化高度敏感。提出了描述在此背景下河岸带水文功能的概念框架，以概括本研究的发现。
Abstract: Identifying relationships between landscape hydrogeological setting, riparian hydrological functioning and riparian zone sensitivity to climate and water quality changes is critical in order to best use riparian zones as best management practices in the future. In this study, we investigate water table dynamics, water flow path and the relative importance of precipitation, deep ground water (DG) and seep water as sources of water to a riparian zone in a deeply incised glacial till valley of the Midwest. Data indicate that water table fluctuations are strongly influenced by soil texture and to a lesser extent by upland sediment stratigraphy producing seeps near the slope bottom. The occurrence of till in the upland and at 1.7‐2 m in the riparian zone contributes to maintaining flow parallel to the ground surface at this site. Lateral ground‐water fluxes at this site with a steep topography in the upland (16%) and loam soil near the slope bottom are small (<10 l/d/m stream length) and intermittent. A shift in flow path from a lateral direction to a down valley direction is observed in the summer despite the steep concave topography and the occurrence of seeps at the slope bottom. Principal component and discriminant analysis indicate that riparian water is most similar to seep water throughout the year and that DG originating from imbedded sand and gravel layers in the lower till unit is not a major source of water to riparian zones in this setting. Water quality data and the dependence of the riparian zone for recharge on seep water suggest that sites in this setting may be highly sensitive to changes in precipitation and water quality in the upland in the future. A conceptual framework describing the hydrological functioning of riparian zones on this setting is presented to generalize the finding of this study.