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| Titel |
Factors affecting the spatial patterns of soil infiltration capacity at the hillslope scale |
| VerfasserIn |
Winnie Seifert, Anna Coles, Willemijn Appels, Luisa Hopp, Jeffrey McDonnell |
| 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 |
250096335
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| Publikation (Nr.) |
 EGU/EGU2014-11833.pdf |
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| Zusammenfassung |
| The quantification of soil infiltration capacity (Ic) and its relation to soil properties have been
the subject of many studies in the past decades. However, the controls on the spatial
organization of infiltration capacity in the landscape are still poorly understood. A better
understanding of the patterns of Ic is important since these patterns govern runoff
generation and possible threshold runoff responses in low-angled terrain prone to
overland flow. In this study we present spatial patterns of Ic on a 5 ha low-angled
agricultural field in Southern Saskatchewan and explore above- and below-ground
controls.
The study site is located in the semi-arid region of western Canada with a mean annual
precipitation of 350 mm. Runoff on these loess soils (Brown Chernozems) is mainly
generated during spring snowmelt and occurs as infiltration-excess overland flow over frozen
ground. Hillslopes in that region typically have a slope of 1-4%. Infiltration capacity was
measured on the 5 ha field in late summer 2013 at 63 randomly distributed locations, using a
single ring infiltrometer (Cornell Sprinkle Infiltrometer). Geostatistical analyses were
carried out to explore the spatial organization of Ic. Soil depth was measured at 17
locations across the field, the roughness of the soil surface was described for each Ic
measuring location and the microtopography on a 456 cm2 area was determined at 60
locations. Hillslope-scale topographic controls will be examined by correlating
terrain indices with the Ic pattern. Furthermore, three dye tracer experiments with
Brilliant Blue were carried out at a low, medium and high Ic spot to investigate
the question if local scale macroporosity can explain the spatial distribution of
Ic.
Infiltration capacities range from 0 to 79.4 mm h-1 with a median of 11.7 mm h-1 and
show no significant correlation with surface roughness, microtopography or soil depth.
However, first geostatistical analyses suggest that there is a spatial organization of the Ic
pattern. A spherical variogram with a range of 102 m provides the best fit and was used for
the ordinary kriging to generate a map of Ic for the agricultural field. The limited data volume
and the erratic shape of the experimental variogram hold a high degree of uncertainty that
will be examined in detail by further analysis. Confidence intervals for the variogram
will be obtained by Monte Carlo methods. Next steps will be to compute various
terrain indices from a detailed digital elevation model of the field and test their
control on the Ic pattern and to analyze the influence of local scale macroporosity. |
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