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| Titel |
Modelling stream flow and quantifying blue water using a modified STREAM model for a heterogeneous, highly utilized and data-scarce river basin in Africa |
| VerfasserIn |
J. K. Kiptala, M. L. Mul, Y. A. Mohamed, P. Van der Zaag |
| 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. 6 ; Nr. 18, no. 6 (2014-06-19), S.2287-2303 |
| Datensatznummer |
250120390
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| Publikation (Nr.) |
 copernicus.org/hess-18-2287-2014.pdf |
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| Zusammenfassung |
| Integrated water resources management is a combination of managing blue and
green water resources. Often the main focus is on the blue water resources,
as information on spatially distributed evaporative water use is not as
readily available as the link to river flows. Physically based, spatially
distributed models are often used to generate this kind of information. These
models require enormous amounts of data, which can result in equifinality,
making them less suitable for scenario analyses. Furthermore, hydrological
models often focus on natural processes and fail to account for anthropogenic
influences. This study presents a spatially distributed hydrological model
that has been developed for a heterogeneous, highly utilized and data-scarce
river basin in eastern Africa. Using an innovative approach,
remote-sensing-derived evapotranspiration and soil moisture variables for
3 years were incorporated as input data into the Spatial Tools for River
basin Environmental Analysis and Management (STREAM) model. To cater for the
extensive irrigation water application, an additional blue water component
(Qb) was incorporated in the STREAM model to quantify irrigation
water use. To enhance model parameter identification and calibration, three
hydrological landscapes (wetlands, hillslope and snowmelt) were identified
using field data. The model was calibrated against discharge data from five
gauging stations and showed good performance, especially in the simulation of
low flows, where the Nash–Sutcliffe Efficiency of the natural logarithm
(Ens_ln) of discharge were greater than 0.6 in both
calibration and validation periods. At the outlet, the
Ens_ln coefficient was even higher (0.90). During
low flows, Qb consumed nearly 50% of the river flow in the
basin. The Qb model result for irrigation was comparable to the
field-based net irrigation estimates, with less than 20% difference. These
results show the great potential of developing spatially distributed models
that can account for supplementary water use. Such information is important
for water resources planning and management in heavily utilized catchment
areas. Model flexibility offers the opportunity for continuous model
improvement when more data become available. |
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