Simulation of saturated and unsaturated flow in karst systems at catchment scale using a double continuum approach
Simulation of saturated and unsaturated flow in karst systems at catchment scale using a double continuum approach
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DOI：
10.5194/hess-16-3909-2012
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发表时间：
2012-10
影响因子：
6.3
通讯作者：
J. Kordilla;M. Sauter;T. Reimann;T. Geyer
中科院分区：
文献类型：
--
作者：
J. Kordilla;M. Sauter;T. Reimann;T. Geyer
这项工作的目的是使用双连续介质方法模拟岩溶含水层中的饱和和非饱和流。 HydroGeoSphere 代码（Therrien 等人，2006）用于模拟弹簧放电，并使用 Richards 方程和 van Genuchten 参数来表示（1）裂隙基质和（2）通过线性交换项耦合的管道连续体中的流动。通过在饱和模型域底部应用补给边界条件来解释非饱和管道连续体中的快速垂直小规模流动过程。对单个参数以及参数组合进行广泛的敏感性分析。岩溶泉水的瞬态水力响应受到基质孔隙度以及不饱和基质的 van Genuchten 参数的强烈控制，这些参数决定了当管道排水基质时依赖于水头的连续体间水传输。参数组合的敏感性部分揭示了对参数空间的非线性依赖性。对于不属于同一连续体的参数以及涉及交换参数的组合，可以观察到这一点，表明双连续体模型的结果可能描述一定程度的模糊性。重点讨论了 van Genuchten 参数在岩溶系统中非饱和流模拟中的应用。
The objective of this work is the simulation of saturated and unsaturated flow in a karstified aquifer using a double continuum approach. The HydroGeoSphere code (Therrien et al., 2006) is employed to simulate spring discharge with the Richards equations and van Genuchten parameters to represent flow in the (1) fractured matrix and (2) conduit continuum coupled by a linear exchange term. Rapid vertical small-scale flow processes in the unsaturated conduit continuum are accounted for by applying recharge boundary conditions at the bottom of the saturated model domain. An extensive sensitivity analysis is performed on single parameters as well as parameter combinations. The transient hydraulic response of the karst spring is strongly controlled by the matrix porosity as well as the van Genuchten parameters of the unsaturated matrix, which determine the head dependent inter-continuum water transfer when the conduits are draining the matrix. Sensitivities of parameter combinations partially reveal a non-linear dependence over the parameter space. This can be observed for parameters not belonging to the same continuum as well as combinations, which involve the exchange parameter, showing that results of the double continuum model may depict a certain degree of ambiguity. The application of van Genuchten parameters for simulation of unsaturated flow in karst systems is critically discussed.