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| Titel |
Spatial variability of streamwater chemistry and specific discharge during low flow periods - First results from snapshot sampling campaigns in thirteen Swiss catchments |
| VerfasserIn |
Marius Floriancic, Benjamin Fischer, Ilja van Meerveld |
| 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 |
250153688
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| Publikation (Nr.) |
 EGU/EGU2017-18698.pdf |
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| Zusammenfassung |
| Catchments consist of different landscape elements that store and release water
differently. Few studies looked at which landscape elements contribute to streamflow
during extended dry periods and whether these elements are similar in different
catchments.
We present a unique dataset from snapshot field campaigns in thirteen watersheds in
Switzerland during low flow conditions in winter and summer 2016. The 10 to 110 km2
catchments varied from predominantly agricultural to alpine environments. In each campaign
streamflow was measured and stream water was collected at a high spatial resolution using a
nested sampling approach. Streamflow during the campaigns was less than the 65th
percentile. We analyzed the water samples for the main ions and isotopic composition (Ca,
Mg, SO4, F, NO3, Na, K, δ18O and δ2H) and compared the results with long-term datasets
from the Swiss National Groundwater and River Monitoring Program (NAQUA and
NADUF). For every sampling location, we calculated local and upslope catchment
characteristics, including area, slope, flow length, topographic wetness index and
elevation. Additionally, we determined land use, soil type and depth, geological
and geomorphological characteristics from existing geodata for every sampling
location.
First analyses show that the spatial variation in water chemistry, isotopic composition and
specific discharge is very high: Neighboring sampling locations could differ significantly in
their specific discharge and isotopic and ion composition (up to a factor of 10), indicating
different contributing sources. Water at the outlet was a mixture of water from different parts
of the catchment. These first results suggest that the combination of snapshot water sampling
and discharge measurements provides a valuable tool for identifying the spatial variability of
contributing sources to streamflow. This information can then later be used to better constrain
hydrological models and predict available water resources during extended dry
periods. |
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