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| Titel |
An efficient semi-distributed hillslope erosion model for the subhumid Ethiopian Highlands |
| VerfasserIn |
S. A. Tilahun, C. D. Guzman, A. D. Zegeye, T. A. Engda, A. S. Collick, A. Rimmer, T. S. Steenhuis |
| 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 ; 17, no. 3 ; Nr. 17, no. 3 (2013-03-08), S.1051-1063 |
| Datensatznummer |
250018822
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| Publikation (Nr.) |
 copernicus.org/hess-17-1051-2013.pdf |
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| Zusammenfassung |
| Erosion modeling has been generally scaling up from plot scale but not based
on landscape topographic position, which is a main variable in saturation
excess runoff. In addition, predicting sediment loss in Africa has been
hampered by using models developed in western countries and
do not perform as well in the monsoon climate prevailing in most of the
continent. The objective of this paper is to develop a simple erosion model
that can be used in the Ethiopian Highlands in Africa. We base our sediment
prediction on a simple distributed saturated excess hydrology model that
predicts surface runoff from severely degraded lands and from bottom lands
that become saturated during the rainy season and estimates interflow and
baseflow from the remaining portions of the landscape. By developing an
equation that relates surface runoff to sediment concentration generated
from runoff source areas, assuming that baseflow and interflow are
sediment-free, we were able to predict daily sediment concentrations from the Anjeni
watershed with a Nash–Sutcliffe efficiency ranging from 0.64 to 0.78 using
only two calibrated sediment parameters. Anjeni is a 113 ha watershed in the
17.4 million ha Blue Nile Basin in the Ethiopian Highlands. The discharge of
the two watersheds was predicted with Nash–Sutcliffe efficiency values
ranging from 0.80 to 0.93. The calibrated values in Anjeni for degraded
(14%) and saturated (2%) runoff source area were in agreement with
field evidence. The analysis suggests that identifying the runoff source
areas and predicting the surface runoff correctly is an important step in
predicting the sediment concentration. |
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