A dual‐domain mass transfer approach for modeling solute transport in heterogeneous aquifers: Application to the Macrodispersion Experiment (MADE) site

Feehley, C. Erin; Chen, Kewei; Molz, Fred J.

doi:10.1029/2000wr900148

Cited by 214 publications

(237 citation statements)

References 55 publications

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“…[36] The plausible hydrogeological explanation for the ''nonideal'' transport behavior observed at the MADE site supports three types of modeling methods, which include the following: (1) the second-order ADE with a fine-scale velocity field capturing both the multiscale flow paths and relatively immobile, trapping zones [Zheng and Jiao, 1998;Eggleston and Rojstaczer, 1998;Zheng and Gorelick, 2003;Zinn and Harvey, 2003;Liu et al, 2004]; (2) the dualdomain approach with a relatively coarse (upscaled) flow field [Harvey and Gorelick, 2000;Feehley et al, 2000;Julian et al, 2001]; and (3) novel nonlocal techniques, such as the CTRW method [Berkowitz and Scher, 1998] and the fADE method , which directly capture the anomalous transport process, using a very coarse, or even a constant, mean transport velocity. An exceptional case of the first method was discussed recently by Barlebo et al [2004], who showed that the second-order ADE with a simplified zonal conductivity (K) field can also characterize the positively skewed plume at the MADE site.…”

Section: Anomalous Transport and Previous Modeling Methodsmentioning

confidence: 99%

Space‐fractional advection‐dispersion equations with variable parameters: Diverse formulas, numerical solutions, and application to the Macrodispersion Experiment site data

Zhang

Benson

Meerschaert

et al. 2007

Water Resources Research

127

123

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[1] To model the observed local variation of transport speed, an extension of the homogeneous space-fractional advection-dispersion equation (fADE) to more general cases with space-dependent coefficients (drift velocity V and dispersion coefficient D) has been suggested. To provide a rigorous evaluation of this extension, we explore the underlying physical meanings of two proposed, and one other possible form, of the fADE by using the generalized mass balance law proposed by Meerschaert et al. (2006). When the classical Fick's law is replaced by its generalized form in the first-order mass conversation law, the original fADE with constant parameters extends to the advection-dispersion equation (ADE) with fractional flux (denoted as FF-ADE). When the net inflow of dispersive flux is from nonlocal concentration gradients following a fractional divergence, we get the ADE with fractional divergence (FD-ADE). When the total net inflow from both nonlocal advection and nonlocal concentration gradients follows a fractional form, the fADE contains fully fractional divergence (FFD-ADE). These three fADEs with constant parameters can also be obtained by proper choice of the two memory kernels in the nonlocal dispersive constitutive theory proposed by Cushman et al. (1994), while the space-variable fADEs correspond to the conditional nonlocal theory proposed by Neuman (1993) after specifying the general (Lévy-type) functional form of the random distribution. The corresponding Langevin Markov models can be found in many cases, where the Lagrangian stochastic processes can be conditioned directly on local aquifer properties at any practical, measurable level and resolution. The resulting Lagrangian random-walk particle tracking methods, along with previous numerical solutions using implicit Euler finite differences, distinguish and elucidate the plume behavior described by these fADEs. The fractional models are applied to fit the tritium plumes measured at the Macrodispersion Experiment test site. When the local parameters gleaned from the hydraulic conductivity (K) distribution are varied even slightly (i.e., a two-zone model), allowing the use of observed hydraulic conditions at the site, the model fits are well within the variability of the data. The extended fADEs describe the fast and space-dependent leading edges of measured plumes in the regional-scale alluvial system, which was underestimated and could not be fully captured by the original fADE with constant parameters. Applications also favor the FD-ADE model because of the ease of implementation and consistency with previous analysis of the K statistics.

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Section: Anomalous Transport and Previous Modeling Methodsmentioning

confidence: 99%

Space‐fractional advection‐dispersion equations with variable parameters: Diverse formulas, numerical solutions, and application to the Macrodispersion Experiment site data

Zhang

Benson

Meerschaert

et al. 2007

Water Resources Research

127

123

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“…Among those, the MIM (Van Genuchten and Wierenga, 1976), has showed to provide better fits of BTCs (Gao et al, 2009;Schumer et al, 2003;Feehley et al, 2010).…”

Section: Cherubini Et Al: On the Reliability Of Analytical Modelsmentioning

confidence: 99%

On the reliability of analytical models to predict solute transport in a fracture network

Cherubini

Giasi

Pastore

2014

Hydrol. Earth Syst. Sci.

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Abstract. In hydrogeology, the application of reliable tracer transport model approaches is a key issue to derive the hydrodynamic properties of aquifers.Laboratory-and field-scale tracer dispersion breakthrough curves (BTC) in fractured media are notorious for exhibiting early time arrivals and late time tailing that are not captured by the classical advection-dispersion equation (ADE). These "non-Fickian" features are proven to be better explained by a mobile-immobile (MIM) approach. In this conceptualization the fractured rock system is schematized as a continuous medium in which the liquid phase is separated into flowing and stagnant regions.The present study compares the performances and reliabilities of the classical MIM and the explicit network model (ENM), taking expressly into account the network geometry for describing tracer transport behavior in a fractured sample at bench scale. Though ENM shows better fitting results than MIM, the latter remains still valid as it proves to describe the observed curves quite well.The results show that the presence of nonlinear flow plays an important role in the behavior of solute transport. First, the distribution of solute according to different pathways is not constant, but it is related to the flow rate. Second, nonlinear flow influences advection in that it leads to a delay in solute transport respect to the linear flow assumption. However, nonlinear flow is not shown to be related with dispersion. The experimental results show that in the study case the geometrical dispersion dominates the Taylor dispersion. However, the interpretation with the ENM shows a weak transitional regime from geometrical dispersion to Taylor dispersion for high flow rates. Incorporating the description of the flow paths in the analytical modeling has proven to better fit the curves and to give a more robust interpretation of the solute transport.

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“…Note that the kriging means are set to the low boundary values of the NST concentration values, to ensure that the interpolated values located far away from the plume are equal to the background natural concentration after back transformation. Based on the field observations and on previous interpolations of the Tritium plume at day 328 (Feehley et al, 2000), it can be asserted that the entirety of the plume stays within the model boundaries. Then to keep the mass consistency between the simulations and the reference at day 328, the back-transformed interpolated concentration field is normalized so that the observed mass at day 328 is the same as at day 27.…”

Section: Interpolations Of the Concentration Datamentioning

confidence: 99%

“…Furthermore, this experiment has been modeled by numerous teams (Feehley et al, 2000;Barlebo et al, 2004;Salamon et al, 2007;Guan et al, 2008;Llopis-Albert and Capilla, 2009), which will facilitate the comparison and the interpretation of the resulting plumes.…”

Section: The Made Sitementioning

confidence: 99%

Influence of conceptual model uncertainty on contaminant transport forecasting in braided river aquifers

Pirot

Renard

Huber

et al. 2015

Journal of Hydrology

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Keywords:Uncertainty Contaminant transport Modeling Braided river Aquifer Groundwater s u m m a r y Hydrogeologist are commonly confronted to field data scarcity. An interesting way to compensate this data paucity, is to use analog data. Then the questions of prediction accuracy and uncertainty assessment when using analog data shall be raised. These questions are investigated in the current paper in the case of contaminant transport forecasting in braided river aquifers. In using analog data from the literature, multiple unconditional geological realizations are produced following different geological conceptual models (Multi-Gaussian, Object-based, Pseudo-Genetic). These petrophysical realizations are tested in a contaminant transport problem based on the MADE-II tracer experiment dataset. The simulations show that reasonable contaminant transport predictions can be achieved using analog data. The initial concentration conditions and location regarding the conductivity heterogeneity field have a stronger influence on the plume behavior than the resulting equivalent permeability. The results also underline the necessity to include a wide variety of geological conceptual models and not to restrain parameter space exploration within each concept as long as no field data allows for conceptual model or parameter value falsification.

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A dual‐domain mass transfer approach for modeling solute transport in heterogeneous aquifers: Application to the Macrodispersion Experiment (MADE) site

Cited by 214 publications

References 55 publications

Space‐fractional advection‐dispersion equations with variable parameters: Diverse formulas, numerical solutions, and application to the Macrodispersion Experiment site data

Space‐fractional advection‐dispersion equations with variable parameters: Diverse formulas, numerical solutions, and application to the Macrodispersion Experiment site data

On the reliability of analytical models to predict solute transport in a fracture network

Influence of conceptual model uncertainty on contaminant transport forecasting in braided river aquifers

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