Comparison of a karst groundwater model with and without discrete conduit flow
Comparison of a karst groundwater model with and without discrete conduit flow
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DOI：
10.1007/s10040-013-1036-6
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发表时间：
2013-09
影响因子：
2.8
通讯作者：
S. P. Saller;M. Ronayne;A. J. Long
中科院分区：
文献类型：
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作者：
S. P. Saller;M. Ronayne;A. J. Long
岩溶含水层表现出一个双重流动系统，其特征是相互作用的导管和基质域。本研究评估了耦合连续管流框架模拟岩溶地下水流在麦迪逊含水层西部南达科他州（美国）。耦合管道和基质流在一个区域有限差分模型内模拟了10年的瞬态期。对现有的等效多孔介质模型进行了修改，以包括主要管道网络，其位置受到染料示踪数据和环境示踪剂分析的约束。模型校准数据包括观测威尔斯井的实测水头和四个岩溶泉的流量估计。相对于常规模型，增加导管后，与观测井水头的匹配得到了显著改善。管道流的列入允许一个更简单的水力传导率分布在基质连续。新模型中删除了间接模拟管道效应所需的两个高传导率区域。这项工作演示了耦合连续管流方法的实用性，并说明了岩溶含水层模型参数化是如何依赖于模拟的物理过程。
Karst aquifers exhibit a dual flow system characterized by interacting conduit and matrix domains. This study evaluated the coupled continuum pipe-flow framework for modeling karst groundwater flow in the Madison aquifer of western South Dakota (USA). Coupled conduit and matrix flow was simulated within a regional finite-difference model over a 10-year transient period. An existing equivalent porous medium (EPM) model was modified to include major conduit networks whose locations were constrained by dye-tracing data and environmental tracer analysis. Model calibration data included measured hydraulic heads at observation wells and estimates of discharge at four karst springs. Relative to the EPM model, the match to observation well hydraulic heads was substantially improved with the addition of conduits. The inclusion of conduit flow allowed for a simpler hydraulic conductivity distribution in the matrix continuum. Two of the high-conductivity zones in the EPM model, which were required to indirectly simulate the effects of conduits, were eliminated from the new model. This work demonstrates the utility of the coupled continuum pipe-flow method and illustrates how karst aquifer model parameterization is dependent on the physical processes that are simulated.