Uncertainty analysis of groundwater flow and solute transport in unsaturated-saturated porous medium: Maricopa case

Persistent Link:
http://hdl.handle.net/10150/280222
Title:
Uncertainty analysis of groundwater flow and solute transport in unsaturated-saturated porous medium: Maricopa case
Author:
Wang, Wenbin
Issue Date:
2002
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Various methods are used to postulate, compare and rank alternative conceptual-mathematical models of unsaturated flow and transport during infiltration and tracer experiments at the Maricopa Agricultural Center (MAC) near Phoenix, Arizona. The models include one- and two-dimensional flow and transport in a uniform soil, a soil consisting of uniform layers, and a stratified soil having laterally varying properties. Characterization of the soil as a uniform medium is based on information obtained from public sources. Characterization of the soil as a layered medium is based on site data. Soil hydraulic properties are estimated from pedologic data. Uniform soil hydraulic properties are ascribed to each layer on the basis of soil type using mean values of three generic databases. Variable soil hydraulic properties are ascribed to individual soil samples using pedotransfer models based on site soil data. By treating these variable hydraulic property estimates as measurements, Bayesian updates of their mean values together with the variance of each estimate are obtained. Geostatistical analysis of soil pedologic and hydraulic properties provides support for a layered conceptual model with relatively large-scale lateral variability in each layer. The above conceptual-mathematical models and hydraulic parameter estimates are applied to analyze flow and transport under uncertainty and to compare simulated and observed water contents during one of the infiltration experiments at the MAC. It is shown that in order to reproduce observed behavior, it is necessary to further modify the hydraulic parameter estimates through inverse modeling. Various conceptual-mathematical models and parameter estimates are compared and ranked using likelihood-based model discrimination criteria. The inverse results are confirmed by using those to simulate the flow of an earlier experiment. Finally, the inverse estimates of soil hydraulic parameters based on one infiltration experiment are used for solute transport modeling. An advection-dispersion model with linear mass transfer to and from a zone of immobile water, or anion exclusion, is employed in forward and inverse modes. The study illustrates how a combination of methods and data sets can be used sequentially and in tandem to improve one's understanding of unsaturated flow and transport conditions at a site.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Hydrology.; Agriculture, Soil Science.; Environmental Sciences.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Hydrology and Water Resources
Degree Grantor:
University of Arizona
Advisor:
Neuman, Shlomo P.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleUncertainty analysis of groundwater flow and solute transport in unsaturated-saturated porous medium: Maricopa caseen_US
dc.creatorWang, Wenbinen_US
dc.contributor.authorWang, Wenbinen_US
dc.date.issued2002en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractVarious methods are used to postulate, compare and rank alternative conceptual-mathematical models of unsaturated flow and transport during infiltration and tracer experiments at the Maricopa Agricultural Center (MAC) near Phoenix, Arizona. The models include one- and two-dimensional flow and transport in a uniform soil, a soil consisting of uniform layers, and a stratified soil having laterally varying properties. Characterization of the soil as a uniform medium is based on information obtained from public sources. Characterization of the soil as a layered medium is based on site data. Soil hydraulic properties are estimated from pedologic data. Uniform soil hydraulic properties are ascribed to each layer on the basis of soil type using mean values of three generic databases. Variable soil hydraulic properties are ascribed to individual soil samples using pedotransfer models based on site soil data. By treating these variable hydraulic property estimates as measurements, Bayesian updates of their mean values together with the variance of each estimate are obtained. Geostatistical analysis of soil pedologic and hydraulic properties provides support for a layered conceptual model with relatively large-scale lateral variability in each layer. The above conceptual-mathematical models and hydraulic parameter estimates are applied to analyze flow and transport under uncertainty and to compare simulated and observed water contents during one of the infiltration experiments at the MAC. It is shown that in order to reproduce observed behavior, it is necessary to further modify the hydraulic parameter estimates through inverse modeling. Various conceptual-mathematical models and parameter estimates are compared and ranked using likelihood-based model discrimination criteria. The inverse results are confirmed by using those to simulate the flow of an earlier experiment. Finally, the inverse estimates of soil hydraulic parameters based on one infiltration experiment are used for solute transport modeling. An advection-dispersion model with linear mass transfer to and from a zone of immobile water, or anion exclusion, is employed in forward and inverse modes. The study illustrates how a combination of methods and data sets can be used sequentially and in tandem to improve one's understanding of unsaturated flow and transport conditions at a site.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectHydrology.en_US
dc.subjectAgriculture, Soil Science.en_US
dc.subjectEnvironmental Sciences.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineHydrology and Water Resourcesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorNeuman, Shlomo P.en_US
dc.identifier.proquest3073273en_US
dc.identifier.bibrecord.b43479091en_US
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