Chemical and isotopic evidence for irrigation return flow in Avra Valley, Arizona.

Persistent Link:
http://hdl.handle.net/10150/191291
Title:
Chemical and isotopic evidence for irrigation return flow in Avra Valley, Arizona.
Author:
Hess, Gregory Scott.
Issue Date:
1992
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:
Nineteen ground-water samples were collected from municipal drinking water wells and private irrigation wells in Avra Valley, Arizona, for the purpose of identifying ground water that has been impacted by irrigation return flow. Nitrate concentrations, stable isotopic ratios of carbon, oxygen, and hydrogen, chloride/bromide ratios, electrical conductivity, and carbon-14 activity were evaluated with respect to land-use patterns in order to determine the effectiveness of using these data to identify irrigation return water. An areal plot of nitrate data indicated that peak concentrations are located in the north-central portion of the valley, where agricultural activity is the most intense. Chloride/bromide ratios in ground water of this area are within the range of natural ground water, indicating that the source of the nitrate is not effluent recharge along the Santa Cruz River. Analyses of the stable isotopes of hydrogen and oxygen were used to identify waters that have been influenced by varying degrees of evaporation. In a plot of 6D versus 60-18, data points representing ground water in irrigated areas fell to the right of the Craig Meteoric Line. Geographically, the distribution of 60-18 values showed trends similar to the distribution of nitrate concentrations. Deuterium-excess parameters calculated from 60-18 and 6D values were lower in irrigated areas than in areas directly downgradient from pristine desert. Carbon-14 analyses indicated that recent recharge has occurred in irrigated areas in northern Avra Valley where elevated nitrate concentrations and heavy 60-18 values are found. The 6C-13 values for Avra Valley ground water appear to be random and are not influenced by irrigation return water.
Type:
Thesis-Reproduction (electronic); text
LCSH Subjects:
Hydrology.; Irrigation water -- Return flow -- Mathematical models.; Groundwater flow -- Arizona -- Avra Valley.
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Long, Austin

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleChemical and isotopic evidence for irrigation return flow in Avra Valley, Arizona.en_US
dc.creatorHess, Gregory Scott.en_US
dc.contributor.authorHess, Gregory Scott.en_US
dc.date.issued1992en_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.abstractNineteen ground-water samples were collected from municipal drinking water wells and private irrigation wells in Avra Valley, Arizona, for the purpose of identifying ground water that has been impacted by irrigation return flow. Nitrate concentrations, stable isotopic ratios of carbon, oxygen, and hydrogen, chloride/bromide ratios, electrical conductivity, and carbon-14 activity were evaluated with respect to land-use patterns in order to determine the effectiveness of using these data to identify irrigation return water. An areal plot of nitrate data indicated that peak concentrations are located in the north-central portion of the valley, where agricultural activity is the most intense. Chloride/bromide ratios in ground water of this area are within the range of natural ground water, indicating that the source of the nitrate is not effluent recharge along the Santa Cruz River. Analyses of the stable isotopes of hydrogen and oxygen were used to identify waters that have been influenced by varying degrees of evaporation. In a plot of 6D versus 60-18, data points representing ground water in irrigated areas fell to the right of the Craig Meteoric Line. Geographically, the distribution of 60-18 values showed trends similar to the distribution of nitrate concentrations. Deuterium-excess parameters calculated from 60-18 and 6D values were lower in irrigated areas than in areas directly downgradient from pristine desert. Carbon-14 analyses indicated that recent recharge has occurred in irrigated areas in northern Avra Valley where elevated nitrate concentrations and heavy 60-18 values are found. The 6C-13 values for Avra Valley ground water appear to be random and are not influenced by irrigation return water.en_US
dc.description.notehydrology collectionen_US
dc.typeThesis-Reproduction (electronic)en_US
dc.typetexten_US
dc.subject.lcshHydrology.en_US
dc.subject.lcshIrrigation water -- Return flow -- Mathematical models.en_US
dc.subject.lcshGroundwater flow -- Arizona -- Avra Valley.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.contributor.chairLong, Austinen_US
dc.contributor.committeememberBassett, Randyen_US
dc.identifier.oclc214118032en_US
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