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| Titel |
Use of soil moisture dynamics and patterns at different spatio-temporal scales for the investigation of subsurface flow processes |
| VerfasserIn |
T. Blume, E. Zehe, A. Bronstert |
| 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 ; 13, no. 7 ; Nr. 13, no. 7 (2009-07-17), S.1215-1233 |
| Datensatznummer |
250011941
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| Publikation (Nr.) |
 copernicus.org/hess-13-1215-2009.pdf |
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| Zusammenfassung |
| Spatial patterns as well as temporal dynamics of soil moisture have a major
influence on runoff generation. The investigation of these dynamics and
patterns can thus yield valuable information on hydrological processes,
especially in data scarce or previously ungauged catchments. The combination
of spatially scarce but temporally high resolution soil moisture profiles
with episodic and thus temporally scarce moisture profiles at additional
locations provides information on spatial as well as temporal patterns of
soil moisture at the hillslope transect scale. This approach is better suited
to difficult terrain (dense forest, steep slopes) than geophysical techniques
and at the same time less cost-intensive than a high resolution grid of
continuously measuring sensors. Rainfall simulation experiments with dye
tracers while continuously monitoring soil moisture response allows for
visualization of flow processes in the unsaturated zone at these locations.
Data was analyzed at different spacio-temporal scales using various graphical
methods, such as space-time colour maps (for the event and plot scale) and
binary indicator maps (for the long-term and hillslope scale). Annual dynamics of
soil moisture and decimeter-scale variability were also investigated. The
proposed approach proved to be successful in the investigation of flow
processes in the unsaturated zone and showed the importance of preferential
flow in the Malalcahuello Catchment, a data-scarce catchment in the Andes of
Southern Chile. Fast response times of stream flow indicate that preferential
flow observed at the plot scale might also be of importance at the hillslope
or catchment scale. Flow patterns were highly variable in space but
persistent in time. The most likely explanation for preferential flow in this
catchment is a combination of hydrophobicity, small scale heterogeneity in
rainfall due to redistribution in the canopy and strong gradients in
unsaturated conductivities leading to self-reinforcing flow paths. |
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