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Titel |
Characterization of deep aquifer dynamics using principal component analysis of sequential multilevel data |
VerfasserIn |
D. Kurtzman, L. Netzer, N. Weisbrod, A. Nasser, E. R. Graber, D. Ronen |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 3 ; Nr. 16, no. 3 (2012-03-08), S.761-771 |
Datensatznummer |
250013209
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Publikation (Nr.) |
copernicus.org/hess-16-761-2012.pdf |
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Zusammenfassung |
Two sequential multilevel profiles were obtained in an observation well
opened to a 130-m thick, unconfined, contaminated aquifer in Tel Aviv,
Israel. While the general profile characteristics of major ions, trace
elements, and volatile organic compounds were maintained in the two sampling
campaigns conducted 295 days apart, the vertical locations of high
concentration gradients were shifted between the two profiles. Principal
component analysis (PCA) of the chemical variables resulted in a first
principal component which was responsible for ∼60% of the
variability, and was highly correlated with depth. PCA revealed three
distinct depth-dependent water bodies in both multilevel profiles, which
were found to have shifted vertically between the sampling events. This
shift cut across a clayey bed which separated the top and intermediate water
bodies in the first profile, and was located entirely within the
intermediate water body in the second profile. Continuous electrical
conductivity monitoring in a packed-off section of the observation well
revealed an event in which a distinct water body flowed through the
monitored section (v ∼ 150 m yr−1). It was concluded that the
observed changes in the profiles result from dominantly lateral flow of
water bodies in the aquifer rather than vertical flow. The significance of
this study is twofold: (a) it demonstrates the utility of sequential
multilevel observations from deep wells and the efficacy of PCA for
evaluating the data; (b) the fact that distinct water bodies of 10 to 100 m
vertical and horizontal dimensions flow under contaminated sites, which has
implications for monitoring and remediation. |
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