 |
| Titel |
Global-scale analysis of river flow alterations due to water withdrawals and reservoirs |
| VerfasserIn |
P. Döll, K. Fiedler, J. Zhang |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 12 ; Nr. 13, no. 12 (2009-12-22), S.2413-2432 |
| Datensatznummer |
250012074
|
| Publikation (Nr.) |
 copernicus.org/hess-13-2413-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| Global-scale information on natural river flows and anthropogenic river flow
alterations is required to identify areas where aqueous ecosystems are
expected to be strongly degraded. Such information can support the
identification of environmental flow guidelines and a sustainable water
management that balances the water demands of humans and ecosystems. This
study presents the first global assessment of the anthropogenic alteration
of river flow regimes, in particular of flow variability, by water
withdrawals and dams/reservoirs. Six ecologically relevant flow indicators
were quantified using an improved version of the global water model
WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river
discharge as affected by human water withdrawals and dams around the year
2000, as well as naturalized discharge without this type of human
interference. Compared to naturalized conditions, long-term average global
discharge into oceans and internal sinks has decreased by 2.7% due to
water withdrawals, and by 0.8% due to dams. Mainly due to irrigation,
long-term average river discharge and statistical low flow Q90 (monthly
river discharge that is exceeded in 9 out of 10 months) have decreased by
more than 10% on one sixth and one quarter of the global land area
(excluding Antarctica and Greenland), respectively. Q90 has increased
significantly on only 5% of the land area, downstream of reservoirs. Due
to both water withdrawals and reservoirs, seasonal flow amplitude has
decreased significantly on one sixth of the land area, while interannual
variability has increased on one quarter of the land area mainly due to
irrigation. It has decreased on only 8% of the land area, in areas
downstream of reservoirs where consumptive water use is low. The impact of
reservoirs is likely underestimated by our study as small reservoirs are not
taken into account. Areas most affected by anthropogenic river flow
alterations are the Western and Central USA, Mexico, the western coast of
South America, the Mediterranean rim, Southern Africa, the semi-arid and
arid countries of the Near East and Western Asia, Pakistan and India,
Northern China and the Australian Murray-Darling Basin, as well as some
Arctic rivers. Due to a large number of uncertainties related e.g. to the
estimation of water use and reservoir operation rules, the analysis is
expected to provide only first estimates of river flow alterations that
should be refined in the future. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|