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Titel |
Vectors of subsurface stormflow in a layered hillslope during runoff initiation |
VerfasserIn |
M. Retter, P. Kienzler, P. F. Germann |
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 ; 10, no. 3 ; Nr. 10, no. 3 (2006-05-10), S.309-320 |
Datensatznummer |
250008057
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Publikation (Nr.) |
copernicus.org/hess-10-309-2006.pdf |
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Zusammenfassung |
The focus is the experimental assessment of in-situ flow vectors in a
hillslope soil. We selected a 100 m2 trenched hillslope study site.
During prescribed sprinkling an obliquely installed TDR wave-guide provides
for the velocity of the wetting front in its direction. A triplet of
wave-guides mounted along the sides of an hypothetical tetrahedron, with its
peak pointing down, produces a three-dimensional vector of the wetting
front. The method is based on the passing of wetting fronts. We analysed 34
vectors along the hillslope at distributed locations and at soil depths from
11 cm (representing top soil) to 40 cm (close to bedrock interface). The
mean values resulted as follows vx=16.1 mm min-1, vy=-0.2 mm min-1,
and vz=11.9 mm min-1. The velocity vectors of the
wetting fronts were generally gravity dominated and downslope orientated.
Downslope direction (x-axis) dominated close to bedrock, whereas no
preference between vertical and downslope direction was found in vectors
close to the surface. The velocities along the contours (y-axis) varied
widely. The Kruskal-Wallis tests indicated that the different upslope
sprinkling areas had no influence on the orientation of the vectors. Vectors
of volume flux density were also calculated for each triplet. The lateral
velocities of the vector approach are compared with subsurface stromflow
collected at the downhill end of the slope. Velocities were 25-140 times
slower than lateral saturated tracer movements on top of the bedrock. Beside
other points, we conclude that this method is restricted to non-complex
substrate (skeleton or portion of big stones). |
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