Revealing the spatial variability of water fluxes at the groundwater-surface water interface
Revealing the spatial variability of water fluxes at the groundwater-surface water interface
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DOI：
10.1002/wrcr.20214
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发表时间：
2013-07-01
影响因子：
5.4
通讯作者：
Zhang, Hao
中科院分区：
文献类型：
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作者：
Binley, Andrew;Ullah, Sami;Zhang, Hao
人们普遍认识到，地下水-地表水界面对富营养地下水向河流转移的模式和形式有重大影响。描述和量化这种影响对于成功管理许多集水区的水资源至关重要，特别是那些受到地下水硝酸盐含量上升威胁的集水区。建立在这样一个集水区以前的实验调查：英国的利斯河，我们报告了一个多测量，多尺度的计划，旨在开发一个概念化的地下水-地表水流动路径沿着200米的范围。这种概念化的关键是垂直和水平水通量的量化，这是通过一系列的达西流的估计加上流中测压计示踪剂稀释试验。这些数据，增强了在河床孔隙水和水上地球物理测量的氯化物浓度的多级测量，揭示了对比的流量组件的贡献沿着河段。在河段的上段，确定了与区域地下水的局部连通性，该连通性似乎抑制了潜流带。进一步下游，水平（横向和纵向）流似乎有助于更多的地下水-地表水界面的总地下流量。虽然河床的水力传导率的变化被观察到，本地化的变化，可以解释流动路径的空间变异性是不明显的。这项研究提供了一个水文概念的网站，这是必不可少的未来的研究，解决土壤地球化学过程，在氮的保留/释放。如果没有一个多实验项目，这样的概念化是不可能的。
There is widespread recognition that the groundwater-surface water interface can have significant influence on the pattern and form of the transfer of nutrient-rich groundwater to rivers. Characterizing and quantifying this influence is critical for successful management of water resources in many catchments, particularly those threatened by rising nitrate levels in groundwater. Building on previous experimental investigations in one such catchment: the River Leith, UK, we report on a multimeasurement, multiscale program aimed at developing a conceptualization of groundwater-surface water flow pathways along a 200 m reach. Key to this conceptualization is the quantification of vertical and horizontal water fluxes, which is achieved through a series of Darcian flow estimates coupled with in-stream piezometer tracer dilution tests. These data, enhanced by multilevel measurements of chloride concentration in riverbed pore water and water-borne geophysical surveying, reveal a contrast in the contribution of flow components along the reach. In the upper section of the reach, a localized connectivity to regional groundwater, that appears to suppress the hyporheic zone, is identified. Further downstream, horizontal (lateral and longitudinal) flows appear to contribute more to the total subsurface flow at the groundwater-surface water interface. Although variation in hydraulic conductivity of the riverbed is observed, localized variation that can account for the spatial variability in flow pathways is not evident. The study provides a hydrological conceptualization for the site, which is essential for future studies which address biogeochemical processes, in relation to nitrogen retention/release. Such a conceptualization would not have been possible without a multiexperimental program.