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| Titel |
Water discharge and sediment flux changes over the past decades in the Lower Mekong River: possible impacts of the Chinese dams |
| VerfasserIn |
X. X. Lu, R. Y. Siew |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2006-03-21), S.181-195 |
| Datensatznummer |
250007981
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| Publikation (Nr.) |
 copernicus.org/hess-10-181-2006.pdf |
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| Zusammenfassung |
| The Lower Mekong River has witnessed extremely low water levels over the
past few years. There is speculation that the changes are a consequence of
the construction and operation of the Chinese cascade dams in the upper part
of the Mekong main stream, the Lancang River. Dam construction on upper
streams can produce a series of induced effects downstream, particularly in
terms of water, sediment, channel and ecological changes. Analyses of
discharge and sediment flux at various gauging stations on the Lower Mekong
River have indicated a disruption in water discharge, water fluctuations and
sediment transport downstream of the first Chinese dam among the 8 cascades
(i.e. the Manwan Dam), after its reservoir was infilled in 1992. Dry season
flows showed a declining trend, and water level fluctuations in the dry
season increased considerably in the post-dam (1993–2000) period. Monthly
suspended sediment concentration (SSC) has also decreased significantly in
several gauging stations in the post-dam period. The estimation of sediment
flux is challenging since the measurements of SSC were sporadic. Our
estimation based on the available data indicated that the areas along the
upper-middle and lowermost reaches of the Mekong River have experienced a
decline in sediment flux, possibly due to sedimentation in the Manwan Dam.
However, the decrease is only statistically significant at the nearest
gauging station below the Dam (i.e. Chiang Saen). Areas located in the
mid-length of the river show less sensitivity to the operation of the Manwan
Dam, as sediment fluxes have remained stable or even increased in the
post-dam period. |
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