Effects of Multiscale Anisotropy on Basin and Hyporheic Groundwater Flow
Effects of Multiscale Anisotropy on Basin and Hyporheic Groundwater Flow
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DOI：
10.1111/j.1745-6584.2010.00775.x
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发表时间：
2011-07
期刊：
影响因子：
2.6
通讯作者：
V. Zlotnik;M. Cardenas;Daniel Toundykov
中科院分区：
文献类型：
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作者：
V. Zlotnik;M. Cardenas;Daniel Toundykov
各种地下水流系统在水力传导率（K）方面表现出小尺度到大尺度各向异性的组合。大尺度各向异性是由系统趋势（例如，K随深度呈指数下降或增加。我们提出了一个通用的二维解决方案，用于计算地形驱动的地下水流，同时考虑K的小尺度和大尺度各向异性。这种解决方案可以应用到不同的系统，任意水头分布和几何形状的地下水位边界，如盆地或潜流。在特殊情况下，该解可简化为著名的均匀各向同性盆地的Tóth模型。我们引入了一个整体的冲洗强度，量化冲洗在不同深度的措施。使用这个解决方案，我们模拟头和流线，并提供在流域中的流结构的分析，相关的盆地分析或潜流。研究表明，小尺度各向异性和大尺度各向异性之间的相互作用强烈控制着流动结构。在经典的Tóth流动模型中，冲刷强度曲线随深度呈准指数下降。新的措施是能够捕捉微妙的变化，在流动结构。我们的研究表明，小尺度和大尺度的各向异性特性都有很大的影响，需要整合到地形驱动流的分析中。
Various subsurface flow systems exhibit a combination of small‐scale to large‐scale anisotropy in hydraulic conductivity (K). The large‐scale anisotropy results from systematic trends (e.g., exponential decrease or increase) of K with depth. We present a general two‐dimensional solution for calculation of topography‐driven groundwater flow considering both small‐ and large‐scale anisotropy in K. This solution can be applied to diverse systems with arbitrary head distribution and geometry of the water table boundary, such as basin or hyporheic flow. In a special case, this solution reduces to the well‐known Tóth model of uniform isotropic basin. We introduce an integral measure of flushing intensity that quantifies flushing at different depths. Using this solution, we simulate heads and streamlines and provide analyses of flow structure in the flow domain, relevant to basin analyses or hyporheic flow. It is shown that interactions between small‐scale anisotropy and large‐scale anisotropy strongly control the flow structure. In the classic Tóth flow model, the flushing intensity curves exhibit quasi‐exponential decrease with depth. The new measure is capable of capturing subtle changes in the flow structure. Our study shows that both small‐ and large‐scale anisotropy characteristics have substantial effects that need to be integrated into analysis of topography‐driven flow.