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| Titel |
A porewater-based stable isotope approach for the investigation of subsurface hydrological processes |
| VerfasserIn |
J. Garvelmann, C. Külls, M. Weiler |
| 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. 2 ; Nr. 16, no. 2 (2012-02-28), S.631-640 |
| Datensatznummer |
250013187
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| Publikation (Nr.) |
 copernicus.org/hess-16-631-2012.pdf |
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| Zusammenfassung |
Predicting and understanding subsurface flowpaths is still a crucial issue
in hydrological research. We present an experimental approach to reveal
present and past subsurface flowpaths of water in the unsaturated and
saturated zone. Two hillslopes in a humid mountainous catchment have been
investigated. The H2O(liquid) – H2O(vapor) equilibration
laser spectroscopy method was used to obtain high resolution δ2H vertical depth profiles of pore water at various points along
two fall lines of a pasture hillslope in the southern Black Forest, Germany. The
Porewater-based Stable Isotope Profile (PSIP) approach was developed to use
the integrated information of several vertical depth profiles of deuterium
along transects at the hillslope.
Different shapes of depth profiles were observed in relation to hillslope
position. The statistical variability (inter-quartile range and standard
deviation) of each profile was used to characterize different types of depth
profiles. The profiles upslope or with a weak affinity for saturation as
indicated by a low topographic wetness index preserve the isotopic input
signal by precipitation with a distinct seasonal variability. These
observations indicate mainly vertical movement of soil water in the upper
part of the hillslope before sampling. The profiles downslope or at
locations with a strong affinity for saturation do not show a similar
seasonal isotopic signal. The input signal is erased in the foothills and a
large proportion of pore water samples are close to the isotopic values of
δ2H in streamwater during base flow conditions indicating the
importance of the groundwater component in the catchment. Near the stream
indications for efficient mixing of water from lateral subsurface flow paths
with vertical percolation are found. |
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