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| Titel |
Transit times of water particles in the vadose zone across catchment states and catchments functional units |
| VerfasserIn |
Matthias Sprenger, Markus Weiler |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086632
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| Publikation (Nr.) |
 EGU/EGU2014-536.pdf |
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| Zusammenfassung |
| Understanding the water movement in the vadose zone and its associated transport of solutes
are of major interest to reduce nutrient leaching, pollution transport or other risks to water
quality. Soil physical models are widely used to asses such transport processes, while the site
specific parameterization of these models remains challenging. Inverse modeling is a
common method to adjust the soil physical parameters in a way that the observed water
movement or soil water dynamics are reproduced by the simulation. We have shown that the
pore water stable isotope concentration can serve as an additional fitting target to simulate the
solute transport and water balance in the unsaturated zone. In the presented study, the
Mualem- van Genuchten parameters for the Richards equation and diffusivity parameter
for the convection-dispersion equation have been parameterized using the inverse
model approach with Hydrus-1D for 46 experimental sites of different land use,
topography, pedology and geology in the Attert basin in Luxembourg. With the
best parameter set we simulated the transport of a conservative solute that was
introduced via a pulse input at different points in time. Thus, the transit times in
the upper 2 m of the soil for different catchment states could be inferred for each
location. It has been shown that the time a particle needs to pass the -2 m depth
plane highly varies from the systems state and the systems forcing during and after
infiltration of that particle. Differences in transit times among the study sites within
the Attert basin were investigated with regards to its governing factors to test the
concept of functional units. The study shows the potential of pore water stable isotope
concentration for residence times and transport analyses in the unsaturated zone leading to a
better understanding of the time variable subsurface processes across the catchment. |
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