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| Titel |
Future changes in Mekong River hydrology: impact of climate change and reservoir operation on discharge |
| VerfasserIn |
H. Lauri, H. Moel, P. J. Ward, T. A. Räsänen, M. Keskinen, M. Kummu |
| 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. 12 ; Nr. 16, no. 12 (2012-12-05), S.4603-4619 |
| Datensatznummer |
250013607
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| Publikation (Nr.) |
 copernicus.org/hess-16-4603-2012.pdf |
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| Zusammenfassung |
| The transboundary Mekong River is facing two ongoing changes that are
expected to significantly impact its hydrology and the characteristics of
its exceptional flood pulse. The rapid economic development of the riparian
countries has led to massive plans for hydropower construction, and projected
climate change is expected to alter the monsoon patterns and increase
temperature in the basin. The aim of this study is to assess the cumulative
impact of these factors on the hydrology of the Mekong within next
20–30 yr. We downscaled the output of five general circulation models
(GCMs) that were found to perform well in the Mekong region. For the
simulation of reservoir operation, we used an optimisation approach to
estimate the operation of multiple reservoirs, including both existing and
planned hydropower reservoirs. For the hydrological assessment, we used a
distributed hydrological model, VMod, with a grid resolution of
5 km × 5 km. In terms of climate change's impact on hydrology, we
found a high variation in the discharge results depending on which of the
GCMs is used as input. The simulated change in discharge at Kratie (Cambodia)
between the baseline (1982–1992) and projected time period (2032–2042)
ranges from −11% to +15% for the wet season and −10% to
+13% for the dry season. Our analysis also shows that the changes in
discharge due to planned reservoir operations are clearly larger than those
simulated due to climate change: 25–160% higher dry season flows and
5–24% lower flood peaks in Kratie. The projected cumulative impacts
follow rather closely the reservoir operation impacts, with an envelope
around them induced by the different GCMs. Our results thus indicate that
within the coming 20–30 yr, the operation of planned hydropower reservoirs
is likely to have a larger impact on the Mekong hydrograph than the impacts
of climate change, particularly during the dry season. On the other hand,
climate change will increase the uncertainty of the estimated reservoir
operation impacts: our results indicate that even the direction of the
flow-related changes induced by climate change is partly unclear.
Consequently, both dam planners and dam operators should pay closer attention
to the cumulative impacts of climate change and reservoir operation on
aquatic ecosystems, including the multibillion-dollar Mekong fisheries. |
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