The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.

Date Permissions Signed

5-12-2018

Date of Award

Summer 2004

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Mitchell, Robert J. (Geologist)

Second Advisor

Babcock, R. Scott (Randall Scott)

Third Advisor

Matthews, Robin A., 1952-

Abstract

The Abbotsford-Sumas aquifer is a shallow, unconfined aquifer located in the agricultural regions of southwestern British Columbia and northwestern Washington and has a history of nitrate contamination. I monitored nitrate distributions in a study area bisected by a wide- scale peat deposit within a portion of the Whatcom County component of the aquifer to assess the current nitrate distribution, evaluate ground and surface water interactions in the peat, and determine the affect of peat on denitrification.

The water quality dataset and statistical analyses showed that nitrate contamination was heavily concentrated upgradient of the peatlands. In general, shallow wells (table) north of the peatlands had higher nitrate concentrations than deeper wells (>10 m below the median water table). Some upgradient wells showed low nitrate concentrations and data suggest they received denitrified ground water from unmapped peat deposits. Nitrogen isotope data (δ15N on nitrate) indicated that nitrate sources included manure and inorganic commercial fertilizers. The contamination south of the peatlands was significantly lower than the contamination to the north and the median nitrate levels within the peatlands were near the detection limit. Nitrogen gas measurements and a combination of nitrogen (δ15N on nitrate) and oxygen (δ180 on water) isotopes confirmed that denitrification occurred in the peatlands and in much of the ground water south of the peatlands. In addition, the gas measurements suggested that iron, manganese, sulfate, and methane occurred throughout the peatlands and may have contributed to redox reductions.

The implication of these findings is that a natural means for nitrate reduction exists in this region. Hydrostratigraphic data suggest that peat deposits occur throughout Whatcom County at various unmapped depths. Identifying these peat deposits and quantifying the upgradient ground water nitrate contributions may help facilitate nutrient management in the region.

Type

Text

Keywords

Abbotsford-Sumas aquifer, Nitrate distributions, Nitrate contaminiation

Publisher

Western Washington University

OCLC Number

1050450215

Geographic Coverage

Sumas Region (Wash.); Abbotsford Region (B.C.)

Genre/Form

masters theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

F1_135-136.xls (180 kB)
Appendix F: Nitrogen Gas Results 1 135-136

F3_137-138.xls (232 kB)
Appendix F: Nitrogen Gas Results 3 137-138

F5_139.xls (175 kB)
Appendix F: Nitrogen Gas Results 5 139

F6_140.xls (169 kB)
Appendix F: Nitrogen Gas Results 6 140

F7_141.xls (175 kB)
Appendix F: Nitrogen Gas Results 7 141

F8_142.xls (109 kB)
Appendix F: Nitrogen Gas Results 8 142

F9_143.xls (115 kB)
Appendix F: Nitrogen Gas Results 9 143

F10_144.xls (115 kB)
Appendix F: Nitrogen Gas Results 10 144

147-170.xls (128 kB)
Appendix G: Data 147-170

171-176.xls (56 kB)
Appendix G: Data 171-176

177-182.xls (50 kB)
Appendix G: Data 177-182

Acronyms.doc (49 kB)
Appendix G: Data Acronyms

Included in

Geology Commons

Share

COinS