Monitoring the transport of salts and water using time domain reflectometry.

Persistent Link:
http://hdl.handle.net/10150/186469
Title:
Monitoring the transport of salts and water using time domain reflectometry.
Author:
Baig, Muhammad Anwar.
Issue Date:
1993
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:
An automated method for the simultaneous measurement of water content, soil water pressure, and soil bulk electrical conductivity in soil columns was developed based on time domain reflectometry (TDR), three wire probes and pressure transducers. Soil electrical conductivity was calculated from the attenuated transmitted pulse, and soil moisture from the trace length and the dielectric constant. The above methodology was used for monitoring breakthrough curves at various depths in soil columns and for determining concentration and ionic composition effects on saturated hydraulic conductivity (HC). Concentration measurements at the inflow and outflow ends were made with mini flow-through cells with mini TDR probes. They were installed in horizontal orientation to intercept the solute fronts. Synthetic irrigation water was sequentially applied to study solute transport. Solute transport parameters were estimated by fitting data to a one dimensional convective dispersive equation, and comparing the results to the moment method of analysis. For moisture content and EC measurements, data acquisition at various depths was fully automated using a multiplexer and auto-relay switching system. Resulting retardation factors (R) and dispersion coefficients (D) were found close to each other for the various probes, and agreed with values obtained from the effluent concentration distributions. The constant flux method, used to determine effects of water quality on saturated hydraulic conductivity, resulted in stable values of saturated hydraulic conductivity. This method clearly showed that measurements of pressure be taken at shallow depths where changes in HC are most pronounced, and occur fast after applying different quality water to the soil.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Hydrology.; Agricultural engineering.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Soil and Water Science; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Wierenga, Peter J.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMonitoring the transport of salts and water using time domain reflectometry.en_US
dc.creatorBaig, Muhammad Anwar.en_US
dc.contributor.authorBaig, Muhammad Anwar.en_US
dc.date.issued1993en_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.abstractAn automated method for the simultaneous measurement of water content, soil water pressure, and soil bulk electrical conductivity in soil columns was developed based on time domain reflectometry (TDR), three wire probes and pressure transducers. Soil electrical conductivity was calculated from the attenuated transmitted pulse, and soil moisture from the trace length and the dielectric constant. The above methodology was used for monitoring breakthrough curves at various depths in soil columns and for determining concentration and ionic composition effects on saturated hydraulic conductivity (HC). Concentration measurements at the inflow and outflow ends were made with mini flow-through cells with mini TDR probes. They were installed in horizontal orientation to intercept the solute fronts. Synthetic irrigation water was sequentially applied to study solute transport. Solute transport parameters were estimated by fitting data to a one dimensional convective dispersive equation, and comparing the results to the moment method of analysis. For moisture content and EC measurements, data acquisition at various depths was fully automated using a multiplexer and auto-relay switching system. Resulting retardation factors (R) and dispersion coefficients (D) were found close to each other for the various probes, and agreed with values obtained from the effluent concentration distributions. The constant flux method, used to determine effects of water quality on saturated hydraulic conductivity, resulted in stable values of saturated hydraulic conductivity. This method clearly showed that measurements of pressure be taken at shallow depths where changes in HC are most pronounced, and occur fast after applying different quality water to the soil.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectHydrology.en_US
dc.subjectAgricultural engineering.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineSoil and Water Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairWierenga, Peter J.en_US
dc.contributor.committeememberWarrick, Arthur W.en_US
dc.contributor.committeememberDutt, Gordon R.en_US
dc.contributor.committeememberFfolliott, Peter F.en_US
dc.identifier.proquest9410670en_US
dc.identifier.oclc721347603en_US
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