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| Titel |
Sedimentation in the Three Gorges Dam and the future trend of Changjiang (Yangtze River) sediment flux to the sea |
| VerfasserIn |
Hu Bangqi, Zuosheng Yang, Houjie Wang, Xiaoxia Sun, Naishuang Bi, Guogang Li |
| 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 ; 13, no. 11 ; Nr. 13, no. 11 (2009-11-26), S.2253-2264 |
| Datensatznummer |
250012062
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| Publikation (Nr.) |
 copernicus.org/hess-13-2253-2009.pdf |
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| Zusammenfassung |
| The Three Gorges Dam (TGD) on the upper Changjiang (Yangtze River), China,
disrupts the continuity of Changjiang sediment delivery to downstream and
coastal areas. In this study, which was based on 54 years of annual water
and sediment data from the mainstream and major tributaries of Changjiang,
sediment deposition induced by the TGD in 2003–2008 was quantified.
Furthermore, we determined the theoretical trapping efficiency of the
cascade reservoir upstream of the TGD. Its impact on Changjiang sediment
flux in the coming decades is discussed. Results show that about 172 million
tons (Mt) of sediment was trapped annually by the TGD in 2003–2008, with an
averaged trapping efficiency of 75%. Most of the total sediment
deposition, as induced by the TGD (88%), accumulated within the region
between the TGD site and Cuntan. However, significant siltation (12% of
the total sediment deposition) also occurred upstream of Cuntan as a
consequence of the upstream extended backwater region of the TGD.
Additionally, the Changjiang sediment flux entered a third downward step in
2001, prior to operation of the TGD. This mainly resulted from sediment
reduction in the Jinshajiang tributary since the late 1990s. As the cascade
reservoir is put into full operation, it could potentially trap 91% of
the Jinshajiang sediment discharge and, therefore, the Jinshajiang sediment
discharge would most likely further decrease to 14 Mt/yr in the coming
decades. Consequently, the Changjiang sediment flux to the sea is expected
to continuously decrease to below 90 Mt/yr in the near future, or only
18% of the amount observed in the 1950s. In the presence of low sediment
discharge, profound impacts on the morphology of estuary, delta and coastal
waters are expected. |
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