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Titel |
Modelling water provision as an ecosystem service in a large East African river basin |
VerfasserIn |
B. Notter, H. Hurni, U. Wiesmann, K. C. Abbaspour |
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. 1 ; Nr. 16, no. 1 (2012-01-10), S.69-86 |
Datensatznummer |
250013113
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Publikation (Nr.) |
copernicus.org/hess-16-69-2012.pdf |
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Zusammenfassung |
Reconciling limited water availability with an increasing demand in a
sustainable manner requires detailed knowledge on the benefits people obtain
from water resources. A frequently advocated approach to deliver such
information is the ecosystem services concept. This study quantifies water
provision as an ecosystem service for the 43 000 km2
Pangani Basin in Tanzania and Kenya. The starting assumption that an
ecosystem service must be valued and accessible by people necessitates the
explicit consideration of stakeholders, as well as fine spatial detail in
order to determine their access to water. Further requirements include the
use of a simulation model to obtain estimates for unmeasured locations and
time periods, and uncertainty assessment due to limited data availability and
quality. By slightly adapting the hydrological model Soil and Water
Assessment Tool (SWAT), developing and applying tools for input
pre-processing, and using Sequential Uncertainty Fitting ver. 2 (SUFI-2) in
calibration and uncertainty assessment, a watershed model is set up according
to these requirements for the Pangani Basin. Indicators for water provision
for different uses are derived from model results by combining them with
stakeholder requirements and socio-economic datasets such as census or water
rights data.
Overall water provision is rather low in the basin, however with large
spatial variability. On average, for domestic use, livestock, and industry,
86–105 l per capita and day (95% prediction uncertainty, 95 PPU) are
available at a reliability level of 95%. 1.19–1.50 ha (95 PPU) of farmland on
which a growing period with sufficient water of 3–6 months is reached at the
75% reliability level – suitable for the production of staple crops – are
available per farming household, as well as 0.19–0.51 ha (95 PPU) of farmland
with a growing period of ≥6 months, suitable for the cultivation of cash
crops.
The indicators presented reflect stakeholder information needs and can
be extracted from the model for any physical or political spatial unit in the
basin. |
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