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Titel |
Assessment of spatial and temporal patterns of green and blue water flows under natural conditions in inland river basins in Northwest China |
VerfasserIn |
C. F. Zang, J. Liu, M. Velde, F. Kraxner |
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. 8 ; Nr. 16, no. 8 (2012-08-21), S.2859-2870 |
Datensatznummer |
250013433
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Publikation (Nr.) |
copernicus.org/hess-16-2859-2012.pdf |
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Zusammenfassung |
In arid and semi-arid regions freshwater resources have become scarcer with
increasing demands from socio-economic development and population growth.
Until recently, water research and management has mainly focused on blue
water but ignored green water. Furthermore, in data poor regions
hydrological flows under natural conditions are poorly characterised but are
a prerequisite to inform future water resources management. Here we report
on spatial and temporal patterns of both blue and green water flows that can
be expected under natural conditions as simulated by the Soil and Water
Assessment Tool (SWAT) for the Heihe river basin, the second largest inland
river basin in Northwest China. Calibration and validation at two
hydrological stations show good performance of the SWAT model in modelling
hydrological processes. The total green and blue water flows were 22.05–25.51 billion m3 in the 2000s for the Heihe river basin. Blue water
flows are larger in upstream sub-basins than in downstream sub-basins mainly
due to high precipitation and a large amount of snow and melting water in
upstream. Green water flows are distributed more homogeneously among
different sub-basins. The green water coefficient was 87%–89% in the
2000s for the entire river basin, varying from around 80%–90% in up-
and mid-stream sub-basins to above 90% in downstream sub-basins. This is
much higher than reported green water coefficients in many other river
basins. The spatial patterns of green water coefficients were closely linked
to dominant land covers (e.g. snow cover upstream and desert downstream) and
climate conditions (e.g. high precipitation upstream and low precipitation
downstream). There are no clear consistent historical trends of change in
green and blue water flows and the green water coefficient at both the river
basin and sub-basin levels. This study provides insights into green and blue
water endowments under natural conditions for the entire Heihe river basin
at the sub-basin level. The results are helpful to benchmark the natural flows
of water in the basin as part of improved water resources management in the
inland river basins of China. |
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