Fragmentation of the Hyporheic Zone Due to Regional Groundwater Circulation
Fragmentation of the Hyporheic Zone Due to Regional Groundwater Circulation
复制标题
区域地下水循环导致潜流带破碎化
DOI：
10.1029/2018wr024609
复制
发表时间：
2019
影响因子：
5.4
通讯作者：
H. Laudon
中科院分区：
文献类型：
--
作者：
B. Mojarrad;J. Riml;A. Wörman;H. Laudon
通过数值模拟和野外观测，本研究量化了流域尺度上涌地下水在大范围空间尺度上对潜流（流下）通量的影响。建立了一个地下水流动模型，专门考虑了由河床地形引起的水静力和动力水头波动。虽然发现这些河床诱导的通量的大小和相对重要性对特定地点的水文形态特性高度敏感，但我们表明，在瑞典北部流域，河床地形结构对潜流交换通量的大小起主要控制作用。在河床界面处的交换强度的大小被河床诱导的水头跨河顺序所控制。然而，集水区尺度的地下水流场实质上影响了地下水排放点的分布，从而减少了暗流带的破碎化，特别是通过将累积密度函数移向河床界面上较大区域的相干上升流。这项工作强调了影响地表水-地下水交换模式的空间尺度谱，并解决了控制潜流带破碎化的关键机制的作用。
By use of numerical modeling and field observations, this work quantified the effects of catchment‐scale upwelling groundwater on the hyporheic (below stream) fluxes over a wide range of spatial scales. A groundwater flow model was developed that specifically accounted for the hydrostatic and dynamic head fluctuations induced by the streambed topography. Although the magnitudes and relative importance of these streambed‐induced fluxes were found to be highly sensitive to site‐specific hydromorphological properties, we showed that streambed topographic structures exert a predominant control on the magnitude of hyporheic exchange fluxes in a Swedish boreal catchment. The magnitude of the exchange intensity evaluated at the streambed interface was found to be dominated by the streambed‐induced hydraulic head across stream order. However, the catchment‐scale groundwater flow field substantially affected the distribution of groundwater discharge points and thus decreased the fragmentation of the hyporheic zone, specifically by shifting the cumulative density function toward larger areas of coherent upwelling at the streambed interface. This work highlights the spectrum of spatial scales affecting the surface water‐groundwater exchange patterns and resolves the roles of key mechanisms in controlling the fragmentation of the hyporheic zone.