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| Titel |
Self-potential investigations of a gravel bar in a restored river corridor |
| VerfasserIn |
N. Linde, J. Doetsch, D. Jougnot, O. Genoni, Y. Dürst, B. J. Minsley, T. Vogt, N. Pasquale, J. Luster |
| 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 ; 15, no. 3 ; Nr. 15, no. 3 (2011-03-04), S.729-742 |
| Datensatznummer |
250012677
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| Publikation (Nr.) |
 copernicus.org/hess-15-729-2011.pdf |
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| Zusammenfassung |
| Self-potentials (SP) are sensitive to water fluxes and concentration
gradients in both saturated and unsaturated geological media, but
quantitative interpretations of SP field data may often be hindered by the
superposition of different source contributions and time-varying electrode
potentials. Self-potential mapping and close to two months of SP monitoring
on a gravel bar were performed to investigate the origins of SP signals at a
restored river section of the Thur River in northeastern Switzerland. The SP
mapping and subsequent inversion of the data indicate that the SP sources
are mainly located in the upper few meters in regions of soil cover rather
than bare gravel. Wavelet analyses of the time-series indicate a strong, but
non-linear influence of water table and water content variations, as well as
rainfall intensity on the recorded SP signals. Modeling of the SP response
with respect to an increase in the water table elevation and precipitation
indicate that the distribution of soil properties in the vadose zone has a
very strong influence. We conclude that the observed SP responses on the
gravel bar are more complicated than previously proposed semi-empiric
relationships between SP signals and hydraulic head or the thickness of the
vadose zone. We suggest that future SP monitoring in restored river
corridors should either focus on quantifying vadose zone processes by
installing vertical profiles of closely spaced SP electrodes or by
installing the electrodes within the river to avoid signals arising from
vadose zone processes and time-varying electrochemical conditions in the
vicinity of the electrodes. |
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