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| Titel |
\begin{center}
Using initial field campaigns for optimal placement of high resolution
stable water isotope and water chemistry measurements
\end{center} |
| VerfasserIn |
Amirhossein Sahraei, Philipp Kraft, David Windhorst, Natalie Orlowski, Konrad Bestian, Hartmut Holly, Lutz Breuer |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142660
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| Publikation (Nr.) |
 EGU/EGU2017-6305.pdf |
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| Zusammenfassung |
| Understanding hydrological processes and flow paths is of major importance for the
management of catchment water resources. The power of stable isotopes as a tracer and to
encoder environmental information provides the opportunity to assess hydrological flow
paths, catchment residence times, landscape influences, and the origin of water resources in
catchments. High resolution isotope sampling of multiple sources ensures detailed
comprehension of hydrological and biogeochemical interactions within catchments.
Technical advances over the last years have made it feasible to directly measure stable
water isotope signatures of various sources online in a high temporal resolution
during field campaigns. However, measuring long time series in a high temporal
resolutions are still costly and can only be performed at few places in a study area.
The identification of locations where measurements should be implemented is still
challenging.
Our study is conducted in the developed landscape of the Schwingbach catchment located
in central Germany. A reconnaissance assessment of the spatial distribution of runoff
generating areas was performed in a short time frame prior to the selection of the final
sampling site. We used a combination of:
water quality snapshot sampling to identify spatial differences and potential hot
spots,
event-based hydrograph separation to differentiate possible flow paths,
consecutive runoff measurements by salt dilution to identify gaining and loosing
reaches,
field reconnaissance mapping of potentially variable source areas in the riparian
zone,
infrared imagery of stream surface temperatures to locate potential concentrated
groundwater discharge to the stream, and
groundwater table mapping to identify sites where different dominant processes
(e.g., groundwater flow, groundwater-surface water interactions and runoff
generation) can be expected.
First results indicated that precipitation and stream water are significantly different in
isotopic composition and groundwater is not reactive to the annual precipitation cycle.
Consecutive runoff measurements revealed bidirectional water exchange between stream
and groundwater where influent and effluent conditions occur at different stream
sections during baseflow conditions. Moreover, stream water quality responds to
land use with significant variation of nitrate concentration due to agricultural land
use.
The a priori assessment of information from various sources and methods will allow us to
guide the placement of high resolution stable water isotope and water chemistry
measurements. We will report on the merits and drawbacks of each approach. Results will be
used to select up to 12 sampling sites for a novel self-sufficient measurement system
and guide the method selection for other researchers facing a similar challenge. |
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