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| Titel |
Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia |
| VerfasserIn |
S. G. Gebrehiwot, U. Ilstedt, A. I. Gärdenas, K. Bishop |
| 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 ; 15, no. 1 ; Nr. 15, no. 1 (2011-01-03), S.11-20 |
| Datensatznummer |
250012582
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| Publikation (Nr.) |
 copernicus.org/hess-15-11-2011.pdf |
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| Zusammenfassung |
| Thirty-two watersheds (31–4350 km2), in the Blue Nile Basin, Ethiopia,
were hydrologically characterized with data from a study of water and land
resources by the US Department of Interior, Bureau of Reclamation (USBR)
published in 1964. The USBR document contains data on flow, topography,
geology, soil type, and land use for the period 1959 to 1963. The aim of the
study was to identify watershed variables best explaining the variation in
the hydrological regime, with a special focus on low flows. Moreover, this
study aimed to identify variables that may be susceptible to management
policies for developing and securing water resources in dry periods.
Principal Component Analysis (PCA) and Partial Least Square (PLS) were used
to analyze the relationship between five hydrologic response variables
(total flow, high flow, low flow, runoff coefficient, low flow index) and 30
potential explanatory watershed variables. The explanatory watershed
variables were classified into three groups: land use, climate and
topography as well as geology and soil type. Each of the three groups had
almost equal influence on the variation in hydrologic variables (R2
values ranging from 0.3 to 0.4). Specific variables from within each of the
three groups of explanatory variables were better in explaining the
variation. Low flow and low flow index were positively correlated to land
use types woodland, dense wet forest and savannah grassland, whereas grazing
land and bush land were negatively correlated. We concluded that extra care
for preserving low flow should be taken on tuffs/basalts which comprise
52% of the Blue Nile Basin. Land use management plans should recognize
that woodland, dense wet forest and savannah grassland can promote higher
low flows, while grazing land diminishes low flows. |
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