 |
| Titel |
Hillslope-scale experiment demonstrates the role of convergence during two-step saturation |
| VerfasserIn |
A. I. Gevaert, A. J. Teuling, R. Uijlenhoet, S. B. DeLong, T. E. Huxman, L. A. Pangle, D. D. Breshears, J. Chorover, J. D. Pelletier, S. R. Saleska, X. Zeng, P. A. Troch |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 9 ; Nr. 18, no. 9 (2014-09-24), S.3681-3692 |
| Datensatznummer |
250120474
|
| Publikation (Nr.) |
 copernicus.org/hess-18-3681-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Subsurface flow and storage dynamics at hillslope scale are difficult to
ascertain, often in part due to a lack of sufficient high-resolution
measurements and an incomplete understanding of boundary conditions, soil
properties, and other environmental aspects. A continuous and extreme
rainfall experiment on an artificial hillslope at Biosphere 2's Landscape
Evolution Observatory (LEO) resulted in saturation excess overland flow and
gully erosion in the convergent hillslope area. An array of 496 soil moisture
sensors revealed a two-step saturation process. First, the downward movement
of the wetting front brought soils to a relatively constant but still
unsaturated moisture content. Second, soils were brought to saturated
conditions from below in response to rising water tables. Convergent areas
responded faster than upslope areas, due to contributions from lateral
subsurface flow driven by the topography of the bottom boundary, which is
comparable to impermeable bedrock in natural environments. This led to the
formation of a groundwater ridge in the convergent area, triggering
saturation excess runoff generation. This unique experiment demonstrates, at
very high spatial and temporal resolution, the role of convergence on
subsurface storage and flow dynamics. The results bring into question the
representation of saturation excess overland flow in conceptual
rainfall-runoff models and land-surface models, since flow is gravity-driven
in many of these models and upper layers cannot become saturated from below.
The results also provide a baseline to study the role of the co-evolution of
ecological and hydrological processes in determining landscape water dynamics
during future experiments in LEO. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|