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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : River bed variations due to sediment bypassing from a reservoir
River bed variations due to sediment bypassing from a reservoir
Author : FONG-ZUO LEE (1), JIHN-SUNG LAI (2), CHENG-CHIA HUANG (3), HUI-MING HSIEH (4) & YIH-CHI TAN (5)
ABSTRACT
The watershed of a reservoir could generate huge amount of sediment yield during typhoon flood or heavy storm event.
Moreover, land development in the watershed would also accelerate soil erosion. As sediment moves into a reservoir,
deposition occurs due to velocity decrease and results in reservoir storage reduction. The Wushe reservoir located in the
central Taiwan has its upland watershed of 219 km2. In recent years, serious deposition problems had been observed in
the Wushe reservoir especially in the upstream delta part of the reservoir. It had been lost two-thirds of its original
capacity according to bathymetric survey in 2013. How to ensure sufficient reservoir storage for water supply and power
generation is always an important issue. In addition, if the modification of outlet structure is made, sediment sluicing
operation should affect downstream river bed variation and water quality at the withdraw intake.
The purpose of this study is to investigate desiltation strategies and impacts of sediment releasing on downstream river
reach between Wushe dam and Wuchieh dam. The strategy of using a bypass tunnel is adopted to reduce
sedimentation impact of Wushe reservoir. The efficiency of sediment bypass obtained from physical model tests is
introduced as the boundary condition for downstream river simulation. A 1D mobile bed model is employed to simulate
the impacts of downstream river after sediment desiltation operation releasing from the Wushe reservoir. Based on
simulated results, desiltation operation by using sediment bypass with other strategies for the Wushe reservoir can keep
downstream river bed more stable. The simulated concentration of suspension sediment during bypassing operation
does not significantly affect the function of withdraw intake at Wuchieh dam for water supply.
File Size : 1,037,680 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 20/08/2015
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