A field comparison of multiple techniques to quantify groundwater–surface-water interactions
A field comparison of multiple techniques to quantify groundwater–surface-water interactions
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DOI：
10.1086/679738
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发表时间：
2015-01
影响因子：
1.8
通讯作者：
R. González‐Pinzón;A. Ward;C. Hatch;A. Wlostowski;K. Singha;M. Gooseff;R. Haggerty;J. Harvey;O. Cirpka;J. Brock
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文献类型：
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作者：
R. González‐Pinzón;A. Ward;C. Hatch;A. Wlostowski;K. Singha;M. Gooseff;R. Haggerty;J. Harvey;O. Cirpka;J. Brock
由于在一系列空间和时间尺度上水力和反应过程的异质性，溪流中地下水-地表水（GW-SW）的相互作用很难量化。量化这些相互作用的挑战导致了多种技术的发展，从厘米级探针到全系统示踪剂，包括化学、热和电方法。我们共同应用了保守和智能反应溶质示踪剂测试、水头测量、分布式温度传感、溶质示踪剂和河床温度的垂直剖面，以及三级流 450 米范围内的电阻率成像。 GW-SW 相互作用在空间上并不广泛，但通过河段周围的浅流带具有高通量。氯化钠和刃天青示踪剂表明河段上部 ⅔ 和下部 ⅓ 存在不同的地表-地下交换模式。示踪剂的地下采样和垂直热剖面量化了通过 10 至 20 厘米深的潜流区的相对较高的通量，在 3、6 和 9 厘米采样深度处显示了刃天青示踪剂的化学反应性。使用距河流约 40 m 处的 MINIPOINT 河床采样器对沿横断面的水力梯度进行监测表明，地下水排放阻止了更大的潜流带的发展，该潜流带从河流海带向河岸逐渐减小。分布式温度传感没有检测到地下水大量流入河流，电阻率成像显示有限的大规模潜流交换。我们建议选择基于以下因素的技术：1）要解决的问题（物理、生物或化学过程）的明确定义，2）要涵盖的空间和时间尺度的明确识别以及为解释提供适当背景所需的空间和时间尺度，以及3）通过合作研究最大限度地产生机械理解并降低实施多种技术的成本。
Groundwater–surface-water (GW-SW) interactions in streams are difficult to quantify because of heterogeneity in hydraulic and reactive processes across a range of spatial and temporal scales. The challenge of quantifying these interactions has led to the development of several techniques, from centimeter-scale probes to whole-system tracers, including chemical, thermal, and electrical methods. We co-applied conservative and smart reactive solute-tracer tests, measurement of hydraulic heads, distributed temperature sensing, vertical profiles of solute tracer and temperature in the stream bed, and electrical resistivity imaging in a 450-m reach of a 3rd-order stream. GW-SW interactions were not spatially expansive, but were high in flux through a shallow hyporheic zone surrounding the reach. NaCl and resazurin tracers suggested different surface–subsurface exchange patterns in the upper ⅔ and lower ⅓ of the reach. Subsurface sampling of tracers and vertical thermal profiles quantified relatively high fluxes through a 10- to 20-cm deep hyporheic zone with chemical reactivity of the resazurin tracer indicated at 3-, 6-, and 9-cm sampling depths. Monitoring of hydraulic gradients along transects with MINIPOINT streambed samplers starting ∼40 m from the stream indicated that groundwater discharge prevented development of a larger hyporheic zone, which progressively decreased from the stream thalweg toward the banks. Distributed temperature sensing did not detect extensive inflow of ground water to the stream, and electrical resistivity imaging showed limited large-scale hyporheic exchange. We recommend choosing technique(s) based on: 1) clear definition of the questions to be addressed (physical, biological, or chemical processes), 2) explicit identification of the spatial and temporal scales to be covered and those required to provide an appropriate context for interpretation, and 3) maximizing generation of mechanistic understanding and reducing costs of implementing multiple techniques through collaborative research.