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Titel |
Classification and flow prediction in a data-scarce watershed of the equatorial Nile region |
VerfasserIn |
J.-M. Kileshye Onema, A. E. Taigbenu, J. Ndiritu |
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 ; 16, no. 5 ; Nr. 16, no. 5 (2012-05-15), S.1435-1443 |
Datensatznummer |
250013298
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Publikation (Nr.) |
copernicus.org/hess-16-1435-2012.pdf |
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Zusammenfassung |
Continuous developments and investigations in flow predictions are of
interest in watershed hydrology especially where watercourses are poorly
gauged and data are scarce like in most parts of Africa. Thus, this paper
reports on two approaches to generate local monthly runoff of the
data-scarce Semliki watershed. The Semliki River is part of the upper
drainage of the Albert Nile. With an average annual local runoff of
4.622 km3/annum, the Semliki watershed contributes up to 20% of the
flows of the White Nile. The watershed was sub-divided in 21 sub-catchments
(S3 to S23). Using eight physiographic and meteorological variables,
generated from remotely sensed acquired datasets and limited catchment data,
monthly runoffs were estimated. One ordination technique, the Principal
Component Analysis (PCA), and the tree cluster analysis of the landform
attributes were performed to study the data structure and spot physiographic
similarities between sub-catchments. The PCA revealed the existence of two
major groups of sub-catchments – flat (Group I) and hilly (Group II).
Linear and nonlinear regression models were used to predict the long-term
monthly mean discharges for the two groups of sub-catchments, and their
performance evaluated by the Nash-Sutcliffe Efficiency (NSE), Percent bias
(PBIAS) and root mean square error to the standard deviation ratio (RSR).
The dimensionless indices used for model evaluation indicate that the non-linear
model provides better prediction of the flows than the linear one. |
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