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Title: Stochastic modeling of macrodispersion in unsaturated heterogeneous porous media. Final report

Abstract

Spatial heterogeneity of geologic media leads to uncertainty in predicting both flow and transport in the vadose zone. In this work an efficient and flexible, combined analytical-numerical Monte Carlo approach is developed for the analysis of steady-state flow and transient transport processes in highly heterogeneous, variably saturated porous media. The approach is also used for the investigation of the validity of linear, first order analytical stochastic models. With the Monte Carlo analysis accurate estimates of the ensemble conductivity, head, velocity, and concentration mean and covariance are obtained; the statistical moments describing displacement of solute plumes, solute breakthrough at a compliance surface, and time of first exceedance of a given solute flux level are analyzed; and the cumulative probability density functions for solute flux across a compliance surface are investigated. The results of the Monte Carlo analysis show that for very heterogeneous flow fields, and particularly in anisotropic soils, the linearized, analytical predictions of soil water tension and soil moisture flux become erroneous. Analytical, linearized Lagrangian transport models also overestimate both the longitudinal and the transverse spreading of the mean solute plume in very heterogeneous soils and in dry soils. A combined analytical-numerical conditional simulation algorithm is also developed to estimatemore » the impact of in-situ soil hydraulic measurements on reducing the uncertainty of concentration and solute flux predictions.« less

Authors:
Publication Date:
Research Org.:
Arizona Univ., Tucson, AZ (United States). Dept. of Hydrology and Water Resources
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10117598
Report Number(s):
DOE/ER/61199-T1
ON: DE95006398; BR: KP0203000; TRN: AHC29508%%166
DOE Contract Number:  
FG02-91ER61199
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ENVIRONMENTAL TRANSPORT; FLOW MODELS; GROUND WATER; POLLUTANTS; ECOLOGICAL CONCENTRATION; SOILS; HYDROLOGY; HYDRAULIC CONDUCTIVITY; PROGRESS REPORT; ALGORITHMS; WATER POLLUTION; 540220; CHEMICALS MONITORING AND TRANSPORT

Citation Formats

Yeh, T C.J. Stochastic modeling of macrodispersion in unsaturated heterogeneous porous media. Final report. United States: N. p., 1995. Web. doi:10.2172/10117598.
Yeh, T C.J. Stochastic modeling of macrodispersion in unsaturated heterogeneous porous media. Final report. United States. https://doi.org/10.2172/10117598
Yeh, T C.J. 1995. "Stochastic modeling of macrodispersion in unsaturated heterogeneous porous media. Final report". United States. https://doi.org/10.2172/10117598. https://www.osti.gov/servlets/purl/10117598.
@article{osti_10117598,
title = {Stochastic modeling of macrodispersion in unsaturated heterogeneous porous media. Final report},
author = {Yeh, T C.J.},
abstractNote = {Spatial heterogeneity of geologic media leads to uncertainty in predicting both flow and transport in the vadose zone. In this work an efficient and flexible, combined analytical-numerical Monte Carlo approach is developed for the analysis of steady-state flow and transient transport processes in highly heterogeneous, variably saturated porous media. The approach is also used for the investigation of the validity of linear, first order analytical stochastic models. With the Monte Carlo analysis accurate estimates of the ensemble conductivity, head, velocity, and concentration mean and covariance are obtained; the statistical moments describing displacement of solute plumes, solute breakthrough at a compliance surface, and time of first exceedance of a given solute flux level are analyzed; and the cumulative probability density functions for solute flux across a compliance surface are investigated. The results of the Monte Carlo analysis show that for very heterogeneous flow fields, and particularly in anisotropic soils, the linearized, analytical predictions of soil water tension and soil moisture flux become erroneous. Analytical, linearized Lagrangian transport models also overestimate both the longitudinal and the transverse spreading of the mean solute plume in very heterogeneous soils and in dry soils. A combined analytical-numerical conditional simulation algorithm is also developed to estimate the impact of in-situ soil hydraulic measurements on reducing the uncertainty of concentration and solute flux predictions.},
doi = {10.2172/10117598},
url = {https://www.osti.gov/biblio/10117598}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 1995},
month = {Wed Feb 01 00:00:00 EST 1995}
}