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| Titel |
A spatially distributed isotope sampling network in a snow-dominated
catchment for the quantification of snow meltwater |
| VerfasserIn |
Andrea Rücker, Stefan Boss, Jana Von Freyberg, Massimiliano Zappa, James Kirchner |
| 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 |
250147744
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| Publikation (Nr.) |
 EGU/EGU2017-11948.pdf |
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| Zusammenfassung |
| In mountainous catchments with seasonal snowpacks, river discharge in downstream valleys
is largely sustained by snowmelt in spring and summer. Future climate warming
will likely reduce snow volumes and lead to earlier and faster snowmelt in such
catchments. This, in turn, may increase the risk of summer low flows and hydrological
droughts. Improved runoff predictions are thus required in order to adapt water
management to future climatic conditions and to assure the availability of fresh water
throughout the year. However, a detailed understanding of the hydrological processes
is crucial to obtain robust predictions of river streamflow. This in turn requires
fingerprinting source areas of streamflow, tracing water flow pathways, and measuring
timescales of catchment storage, using tracers such as stable water isotopes (18O,
2H).
For this reason, we have established an isotope sampling network in the Alptal, a
snowmelt-dominated catchment (46.4 km2) in Central-Switzerland, as part of the
SREP-Drought project (Snow Resources and the Early Prediction of hydrological
DROUGHT in mountainous streams). Precipitation and snow cores are analyzed for their
isotopic signature at daily or weekly intervals. Three-week bulk samples of precipitation are
also collected on a transect along the Alptal valley bottom, and along an elevational transect
perpendicular to the Alptal valley axis. Streamwater samples are taken at the catchment outlet
as well as in two small nested sub-catchments (< 2 km2). In order to catch the
isotopic signature of naturally-occurring snowmelt, a fully automatic snow lysimeter
system was developed, which also facilitates real-time monitoring of snowmelt
events, system status and environmental conditions (air and soil temperature). Three
lysimeter systems were installed within the catchment, in one forested site and two
open field sites at different elevations, and have been operational since November
2016.
We will present the isotope time series from our regular sampling network, as well as
initial results from our snowmelt lysimeter sites. Our data set will allow for detailed
hydrograph separation based on stable water isotopes and geochemical components, which
we use to identify source areas and to quantify snowmelt contributions to streamflow. |
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