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| Titel |
One hillslope does not a watershed make: Analysis of shallow subsurface flow thresholds across 30 hillslopes for six years. |
| VerfasserIn |
Kelsey Jencso, Brian McGlynn, Fabian Nippgen |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129901
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| Publikation (Nr.) |
 EGU/EGU2016-10072.pdf |
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| Zusammenfassung |
| Rainfall-runoff data from single hillslope trench studies around the world have
indicated the presence of precipitation and soil water storage thresholds that are
required for shallow subsurface flow initiation (SSF) and the hydrologic connectivity
between hillslopes and stream networks. However, watersheds are composed of many
hillslopes of varying sizes and topographic organization. We evaluated the relationship
between a simple antecedent precipitation index and the threshold initiation-cessation
of SSF for six contrasting snowmelt seasons (2006-2011) across 24-30 different
hillslopes in the Tenderfoot Creek Experimental Forest, Montana, USA. The thresholds
for SSF initiation and cessation ranged from 0.1-100mm and were exponentially
related to increasing hillslope upslope accumulated area (0.06-4.6 ha). While the
timing of SSF initiation varied from year to year, the magnitude of the threshold
remained relatively consistent for each hillslope across the 6 years of observation
(σ < 15mm). These relationships suggest that the larger watershed runoff-storage
relationship is an integration of the timing and magnitude of precipitation inputs
and the internal organization of hillslope storage dynamics. This is an important
consideration in the context of predicting the sensitivity of runoff source areas to climate
variability and the mixing of landscape source waters and biogeochemical fluxes. |
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