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Titel |
Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia |
VerfasserIn |
M. E. Arias, T. Piman, H. Lauri, T. A. Cochrane, 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 ; 18, no. 12 ; Nr. 18, no. 12 (2014-12-18), S.5303-5315 |
Datensatznummer |
250120571
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Publikation (Nr.) |
copernicus.org/hess-18-5303-2014.pdf |
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Zusammenfassung |
River tributaries have a key role in the biophysical functioning of the
Mekong Basin. Of particular interest are the Sesan, Srepok, and Sekong (3S)
rivers, which contribute nearly a quarter of the total Mekong discharge.
Forty two dams are proposed in the 3S, and once completed they will exceed
the active storage of China's large dam cascade in the Upper Mekong. Given
their proximity to the Lower Mekong floodplains, the 3S dams could alter the
flood-pulse hydrology driving the productivity of downstream ecosystems.
Therefore, the main objective of this study was to quantify how hydropower
development in the 3S, together with definite future (DF) plans for infrastructure
development through the basin, would alter the hydrology of the Tonle Sap's Floodplain, the largest wetland in the Mekong and home to one of the most
productive inland fisheries in the world. We coupled results from four
numerical models representing the basin's surface hydrology, water resources
development, and floodplain hydrodynamics. The scale of alterations caused
by hydropower in the 3S was compared with the basin's DF scenario driven by the Upper Mekong dam cascade. The DF or
the 3S development scenarios could independently increase Tonle Sap's 30-day
minimum water levels by 30 ± 5 cm and decrease annual water level fall
rates by 0.30 ± 0.05 cm day−1. When analyzed together (DF + 3S),
these scenarios are likely to eliminate all baseline conditions (1986–2000)
of extreme low water levels, a particularly important component of Tonle
Sap's environmental flows. Given the ongoing trends and large economic
incentives in the hydropower business in the region, there is a high
possibility that most of the 3S hydropower potential will be
exploited and that dams will be built even in locations where there is a
high risk of ecological disruption. Hence, retrofitting current designs and
operations to promote sustainable hydropower practices that optimize
multiple river services – rather than just maximize hydropower generation – appear to be the most feasible alternative to mitigate hydropower-related
disruptions in the Mekong. |
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