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| Titel |
Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia |
| VerfasserIn |
M. Dessie, N. E. C. Verhoest, V. R. N. Pauwels, T. Admasu, J. Poesen, E. Adgo, J. Deckers, J. Nyssen |
| 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 ; 18, no. 12 ; Nr. 18, no. 12 (2014-12-12), S.5149-5167 |
| Datensatznummer |
250120562
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| Publikation (Nr.) |
 copernicus.org/hess-18-5149-2014.pdf |
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| Zusammenfassung |
| Understanding runoff processes in a basin is of paramount importance for the
effective planning and management of water resources, in particular in data-scarce regions such as the Upper Blue Nile. Hydrological models
representing the underlying hydrological processes can predict river
discharges from ungauged catchments and allow for an understanding of the
rainfall–runoff processes in those catchments. In this paper, such a
conceptual process-based hydrological model is developed and applied to the
upper Gumara and Gilgel Abay catchments (both located within the Upper Blue
Nile Basin, the Lake Tana sub-basin) to study the runoff mechanisms and
rainfall–runoff processes in the basin. Topography is considered as a proxy
for the variability of most of the catchment characteristics. We divided the
catchments into different runoff production areas using topographic
criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in
the Upper Blue Nile Basin) were considered separately in the conceptual
model. Based on model results, it can be inferred that about 65% of the
runoff appears in the form of interflow in the Gumara study catchment, and
baseflow constitutes the larger proportion of runoff (44–48%) in the
Gilgel Abay catchment. Direct runoff represents a smaller fraction of the
runoff in both catchments (18–19% for the Gumara, and 20% for the
Gilgel Abay) and most of this direct runoff is generated through
infiltration excess runoff mechanism from the impermeable rocks or hard soil
pans. The study reveals that the hillslopes are recharge areas (sources of
interflow and deep percolation) and direct runoff as saturated excess flow
prevails from the flat slope areas. Overall, the model study suggests that
identifying the catchments into different runoff production areas based on
topography and including the impermeable rocky areas separately in the
modeling process mimics the rainfall–runoff process in the Upper Blue
Nile Basin well and yields a useful result for operational management of water
resources in this data-scarce region. |
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