Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields

Abstract This work develops a theoretical framework for modeling the large‐scale transport of inert solutes in heterogeneous aquifers, where the perturbation field of logarithmic hydraulic conductivity (lnK) is considered nonstationary. Based on the intrinsic hypothesis for the lnK perturbation fiel...

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Main Authors: Ching‐Min Chang, Chuen‐Fa Ni, Chi‐Ping Lin, I‐Hsian Lee, Wei‐Cheng Lo
Format: Article
Language:English
Published: Wiley 2025-07-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2024WR038722
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author Ching‐Min Chang
Chuen‐Fa Ni
Chi‐Ping Lin
I‐Hsian Lee
Wei‐Cheng Lo
author_facet Ching‐Min Chang
Chuen‐Fa Ni
Chi‐Ping Lin
I‐Hsian Lee
Wei‐Cheng Lo
author_sort Ching‐Min Chang
collection DOAJ
description Abstract This work develops a theoretical framework for modeling the large‐scale transport of inert solutes in heterogeneous aquifers, where the perturbation field of logarithmic hydraulic conductivity (lnK) is considered nonstationary. Based on the intrinsic hypothesis for the lnK perturbation field, the variability of the lnK perturbation field can be characterized by the semivariogram. The general expressions for the concentration semivariogram and the macrodispersive flux in Fourier spectral space are derived using the Fourier‐Stieltjes spectral representation approach and the representation theorem. These solutions generalize the previous results presented in the literature on stochastic subsurface hydrology under the assumption of a stationary covariance function of the lnK perturbation field. The theories developed here are applied to the case of solute transport in heterogeneous media, where the variation of the lnK perturbation field exhibits a power‐law semivariogram. It is shown that the nonstationarity of the lnK perturbation field leads to nonstationary perturbation fields of the hydraulic head and thus of the specific discharge, which in turn results in a nonstationary perturbation field of the concentration, leading to a non‐Fickian macrodispersion. The greater the Hurst exponent, the greater the variability of the specific discharge and solute concentration perturbation fields and thus the greater the macrodispersive flux.
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institution Matheson Library
issn 0043-1397
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language English
publishDate 2025-07-01
publisher Wiley
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series Water Resources Research
spelling doaj-art-ecb918a8f41a45d28ddc55c70730f9a02025-07-29T02:32:50ZengWileyWater Resources Research0043-13971944-79732025-07-01617n/an/a10.1029/2024WR038722Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity FieldsChing‐Min Chang0Chuen‐Fa Ni1Chi‐Ping Lin2I‐Hsian Lee3Wei‐Cheng Lo4Graduate Institute of Applied Geology National Central University Taoyuan TaiwanGraduate Institute of Applied Geology National Central University Taoyuan TaiwanCenter for Environmental Studies National Central University Taoyuan TaiwanCenter for Environmental Studies National Central University Taoyuan TaiwanDepartment of Hydraulic and Ocean Engineering National Cheng Kung University Tainan City TaiwanAbstract This work develops a theoretical framework for modeling the large‐scale transport of inert solutes in heterogeneous aquifers, where the perturbation field of logarithmic hydraulic conductivity (lnK) is considered nonstationary. Based on the intrinsic hypothesis for the lnK perturbation field, the variability of the lnK perturbation field can be characterized by the semivariogram. The general expressions for the concentration semivariogram and the macrodispersive flux in Fourier spectral space are derived using the Fourier‐Stieltjes spectral representation approach and the representation theorem. These solutions generalize the previous results presented in the literature on stochastic subsurface hydrology under the assumption of a stationary covariance function of the lnK perturbation field. The theories developed here are applied to the case of solute transport in heterogeneous media, where the variation of the lnK perturbation field exhibits a power‐law semivariogram. It is shown that the nonstationarity of the lnK perturbation field leads to nonstationary perturbation fields of the hydraulic head and thus of the specific discharge, which in turn results in a nonstationary perturbation field of the concentration, leading to a non‐Fickian macrodispersion. The greater the Hurst exponent, the greater the variability of the specific discharge and solute concentration perturbation fields and thus the greater the macrodispersive flux.https://doi.org/10.1029/2024WR038722intrinsic random functionconcentration semivariogrammacrodispersive fluxFourier‐Stieltjes representation
spellingShingle Ching‐Min Chang
Chuen‐Fa Ni
Chi‐Ping Lin
I‐Hsian Lee
Wei‐Cheng Lo
Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
Water Resources Research
intrinsic random function
concentration semivariogram
macrodispersive flux
Fourier‐Stieltjes representation
title Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
title_full Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
title_fullStr Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
title_full_unstemmed Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
title_short Stochastic Analysis of Macrodispersive Solute Flux in Heterogeneous Aquifers With Nonstationary Random Hydraulic Conductivity Fields
title_sort stochastic analysis of macrodispersive solute flux in heterogeneous aquifers with nonstationary random hydraulic conductivity fields
topic intrinsic random function
concentration semivariogram
macrodispersive flux
Fourier‐Stieltjes representation
url https://doi.org/10.1029/2024WR038722
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AT chipinglin stochasticanalysisofmacrodispersivesolutefluxinheterogeneousaquiferswithnonstationaryrandomhydraulicconductivityfields
AT ihsianlee stochasticanalysisofmacrodispersivesolutefluxinheterogeneousaquiferswithnonstationaryrandomhydraulicconductivityfields
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