Elsevier

CATENA

Volume 199, April 2021, 105096
CATENA

Sedimentation and its response to management strategies of the Three Gorges Reservoir, Yangtze River, China

https://doi.org/10.1016/j.catena.2020.105096Get rights and content
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Highlights

  • Sediment peak regulation is adopted to discharge more sediment downstream.

  • Sediment deposition has been greatly reduced by management methods over 30 years.

  • Fluctuating backwater area of the TGR has been scoured.

Abstract

The Three Gorges Dam (TGD), on the upper valley of the Yangtze River, China, is the largest water conservancy and power generation project in the world. Problematic sedimentation in the Three Gorges Reservoir (TGR) is related to the reservoir lifetime, hydropower generation, riverbed erosion, and sustainable development of ecosystems. In this study, measures to holistically and systematically address sedimentation in the TGR are -discussed and demonstrated, including upstream sediment trapping, regulatory optimisation with respect to sediment peaks and reservoir tail sedimentation reduction, and sediment dredging. Owing to upstream reservoir sediment trapping, the incoming sediment load of the TGR has decreased markedly. Results showed that the annual incoming sediment was only 164 million tons, nearly 70% lesser than the preliminary design value. By intercepting the sediment in the upstream reservoirs and conducting sediment peak regulation, the volume and rates of sedimentation in the TGR decreased significantly. Meanwhile, through sediment peak regulation during the flood season, increased volumes of sediment could be discharged downstream, thereby relieving sediment starvation downstream of the TGD. Overall, through adoption of the related sedimentation management strategies, sediment deposition decreased considerably, to approximately 33% of the preliminary design value, thereby successfully addressing the sediment problems in the TGR. Useful sedimentation management strategies learned from the TGR experience can be applied elsewhere to ensure the sustainable use and management of reservoirs.

Keywords

Sedimentation management
Three Gorges Reservoir
Sediment peak regulation
Sedimentation reduction regulation
Sediment dredging

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