Title: | Assessment of spatial and temporal patterns of green and blue water flows under natural conditions in inland river basins in Northwest China |
Authors: | Zang, C.F., J. Liu, M. van der Velde and F. Kraxner |
Year: | 2012 |
Journal: | Hydrology and Earth System Sciences |
Volume (Issue): | 16 |
Pages: | 2859-2870 |
Article ID: | |
DOI: | 10.5194/hess-16-2859-2012 |
URL (non-DOI journals): | |
Model: | SWAT |
Broad Application Category: | hydrologic only |
Primary Application Category: | blue, green and/or gray water, or crop water productivity |
Secondary Application Category: | hydrologic assessment |
Watershed Description: | 234,000 km^2 Heihe River northwest China (a small portion lies in Mongolia) |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | In arid and semi-arid regions freshwater resources
have become scarcer with increasing demands from socioeconomic
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 midstream
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. |
Language: | English |
Keywords: | |