Estimating surface/ground-water mixing using stable environmental isotopes

Persistent Link:
http://hdl.handle.net/10150/191314
Title:
Estimating surface/ground-water mixing using stable environmental isotopes
Author:
Colgan, Gary A.
Issue Date:
1989
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:
The stable isotopes of oxygen, hydrogen and sulfur were used to establish the mixing relationships between ash-pond waters and ground water at the Utah Power & Light, Company Power Plant in Lincoln County, Wyoming. This coal-fired plant discharges ash-laden water which is isotopically distinct from the local ground water. These environmental isotopes function well as tracers of pond leakage and mixing of discharged water with ground water. The plant is within the southwestern part of the Wyoming thrust belt and lies on west-dipping (10-20 0 ) beds of the Late Cretaceous Hilliard Shale. This marine shale contains abundant gypsum along partings and fissures. Coal for the plant is mined from the Late Cretaceous Adaville Formation, which lies stratigraphically above the Hilliard Shale. The local ground water is non-potable, containing up to 20,000 mg/1 of total dissolved solids (TDS). Sulfate accounts for over 60 percent of the TDS in this predominantly calcium-sulfate water. Ash-pond waters are lower in TDS, generally not exceeding 1000 mg/1, of which sulfate is about 50 percent of the dissolved solids. The plant-process water is obtained by pipeline from the Ham's Fork drainage, ten miles to the north. This water yields discretely different oxygen and hydrogen isotopic values compared to the local ground water. This difference is further enhanced by evaporative enrichment occurring within the discharge ponds. Two isotopically distinct sources of sulfur are observed in this system: (1) sulfate from the combustion of coal, and (2) sulfate from the distribution of gypsum in the Hilliard Shale. Estimates of mixing between discharge water and ground water were calculated from the isotope data. These calculations indicated that, although the plant is contributing substantial volumes of water to the aquifer, ground water is diluted by the mixing of less saline discharge water. This study demonstrates that stable environmental isotopes can be used as estimators of surface/ground-water mixing, especially when isotopically distinguishable sources can be identified.
Type:
Thesis-Reproduction (electronic); text
LCSH Subjects:
Hydrology.; Groundwater tracers.; Groundwater.
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEstimating surface/ground-water mixing using stable environmental isotopesen_US
dc.creatorColgan, Gary A.en_US
dc.contributor.authorColgan, Gary A.en_US
dc.date.issued1989en_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.abstractThe stable isotopes of oxygen, hydrogen and sulfur were used to establish the mixing relationships between ash-pond waters and ground water at the Utah Power & Light, Company Power Plant in Lincoln County, Wyoming. This coal-fired plant discharges ash-laden water which is isotopically distinct from the local ground water. These environmental isotopes function well as tracers of pond leakage and mixing of discharged water with ground water. The plant is within the southwestern part of the Wyoming thrust belt and lies on west-dipping (10-20 0 ) beds of the Late Cretaceous Hilliard Shale. This marine shale contains abundant gypsum along partings and fissures. Coal for the plant is mined from the Late Cretaceous Adaville Formation, which lies stratigraphically above the Hilliard Shale. The local ground water is non-potable, containing up to 20,000 mg/1 of total dissolved solids (TDS). Sulfate accounts for over 60 percent of the TDS in this predominantly calcium-sulfate water. Ash-pond waters are lower in TDS, generally not exceeding 1000 mg/1, of which sulfate is about 50 percent of the dissolved solids. The plant-process water is obtained by pipeline from the Ham's Fork drainage, ten miles to the north. This water yields discretely different oxygen and hydrogen isotopic values compared to the local ground water. This difference is further enhanced by evaporative enrichment occurring within the discharge ponds. Two isotopically distinct sources of sulfur are observed in this system: (1) sulfate from the combustion of coal, and (2) sulfate from the distribution of gypsum in the Hilliard Shale. Estimates of mixing between discharge water and ground water were calculated from the isotope data. These calculations indicated that, although the plant is contributing substantial volumes of water to the aquifer, ground water is diluted by the mixing of less saline discharge water. This study demonstrates that stable environmental isotopes can be used as estimators of surface/ground-water mixing, especially when isotopically distinguishable sources can be identified.en_US
dc.description.notehydrology collectionen_US
dc.typeThesis-Reproduction (electronic)en_US
dc.typetexten_US
dc.subject.lcshHydrology.en_US
dc.subject.lcshGroundwater tracers.en_US
dc.subject.lcshGroundwater.en_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.identifier.oclc218794781en_US
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