The objective of this paper was to identify the incidence and extent of preferential flow at two experimental areas located in Lyon, France. We used time-lapse ground-penetrating radar (GPR) surveys in conjunction with automatized single-ring infiltration experiments to create three-dimensional (3D) representations of infiltrated water. In total we established three 100 cm × 100 cm GPR grids and used differenced radargrams from pre- and post-infiltration surveys to detect wetting patterns. The analyzed time-lapse GPR surveys revealed the linkage between nonuniform flow and heterogeneous soil structures and plant roots. At the first experimental area, subsurface coarse gravels acted as capillary barriers that concentrated flow into narrow pathways via funneled flow. At the second experimental area, the interpolated 3D patterns closely matched direct observation of dyed patterns, thereby validating the applied protocol. They also highlighted the important role of plant roots in facilitating preferential water movement through the subsurface. The protocol presented in this study represents a valuable tool for improving the hydraulic characterization of highly heterogeneous soils, while also alleviating some of the excessive experimental efforts currently needed to detect preferential flow pathways in the field.

中文翻译：

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通过延时穿越地面的雷达调查来检测渗入的水和优先流动路径。

本文的目的是确定位于法国里昂的两个实验区的优先流动的发生率和程度。我们将延时穿地探地雷达（GPR）调查与自动化的单环入渗实验结合使用，以创建渗入水的三维（3D）表示形式。我们总共建立了三个100 cm×100 cm GPR网格，并使用了渗透前和渗透后调查的不同雷达图来检测润湿模式。经过分析的延时GPR调查揭示了非均匀流动与非均质土壤结构和植物根系之间的联系。在第一个实验区域，地下粗糙的砾石充当毛细管屏障，通过漏斗流将其集中到狭窄的通道中。在第二实验区 内插的3D模式紧密匹配染色模式的直接观察，从而验证了所应用的协议。他们还强调了植物根系在促进优先水分通过地下流动方面的重要作用。这项研究中提出的协议是改善高度非均质土壤水力特性的有价值的工具，同时还减轻了目前在现场检测优先流动路径所需的过度实验工作。