Flow separation in undisturbed soil using multiple anionic tracers (2) steady state core scale rainfall and return flows.
Flow separation in undisturbed soil using multiple anionic tracers (2) steady state core scale rainfall and return flows.
复制标题
使用多种阴离子示踪剂在原状土壤中进行水流分离 (2) 稳态核心尺度降雨和回流。
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
N. Chappell
中科院分区：
文献类型：
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作者：
D. Henderson;A. Reeves;K. Beven;N. Chappell
总结了近饱和条件下恒定降雨(向下)和回流(向上)条件下两个大的原状岩心流动组分分离的实验结果。这些实验是在从兰开斯特大学和德文郡斯莱普顿木材集水区收集的土柱上进行的。由于使用了相对保守的示踪剂溴化钾、邻三氟甲基苯甲酸和2，6-二氟苯甲酸，以及各种施用量的组合，因此有可能对造成排放过程线的不同水源进行量化。尽管应用了几个孔隙体积的水，但示踪剂在岩芯中仍有显著的保留。利用恒定流动条件，可以确定对流-弥散方程的弥散系数、弥散率和动水含量比例参数。结果表明，在不同流量下，上、下行流量下的分散度与未扰动岩心的分散度有显著差异，流动孔隙水的表观比例在0.33~1.0之间，与流量的关系明显复杂。对未受扰动的土壤中迁移的预测仍然存在问题，将继续需要示踪实验来提供对所涉及的复杂流动过程的基本了解。
A series of experiments designed to study the separation of flow components from two large undisturbed cores under steady-state rainfall (downward) and return (upward) flows under near-saturated conditions is summarized. The experiments were conducted on soil columns collected from Lancaster University and the Slapton Wood catchment, Devon. The use of the relatively conservative tracers, potassium bromide, o-(trifluoromethyl)benzoic acid and 2,6-difluorobenzoic acid and a combination of application rates made it possible to quantify the different sources of water contributing to the discharge hydrographs. There is significant retention of tracer within the cores, despite the application of several pore volumes of water. The use of steady flow conditions allowed the determination of dispersion coefficients, dispersivity and proportion of mobile water content parameters of the advection-dispersion equation. It was found that there were significant differences between the dispersivities at different flow-rates under upward and downward flux conditions and that in the undisturbed cores studied here the apparent proportions of mobile pore water ranged between 0.33 and 1.0, with an apparently complex relationship to flux rate. Prediction of transport in undisturbed soil remains problematic and tracer experiments will continue to be needed to provide a fundamental understanding of the complex flow processes involved.