IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Sediment starvation from dams in the lower mekong river basin: magnitude of the effect and potential...
Sediment starvation from dams in the lower mekong river basin: magnitude of the effect and potential mitigation opportunities
The Mekong River is undergoing rapid dam construction. Seven mainstem dams are completed or under construction in
China and 133 completed or proposed for the Lower Mekong River basin. We developed geomorphically-based estimates
of sediment yield from different geologic provinces and applied the 3W model to calculate the net sediment trapping from
existing and future proposed dams, using improved methods and data over prior such estimates. Our results indicate that
the 133 dams built as planned would trap 96% of the riverís former sediment supply to the delta, a significantly greater
trapping than prior estimates of 50-75%. The most significant downstream impacts of this sediment-starved water will be
accelerated erosion and subsidence of the delta in response to the virtual elimination of its sediment supply. Upstream,
the mostly bedrock channel upstream of Kratie will have its thin sediment deposits stripped away (with consequences for
aquatic organisms dependent on the alluvium) and the bedrock reach of Vientiane will likely incise. The impacts of daminduced
sediment starvation can be partially mitigated by implementing strategies to pass sediment through or around
dams (e.g., sediment sluicing, flushing, density current venting, and bypasses), and our team is currently working with staff
of Laotian and Cambodian ministries to identify opportunities to relocate/redesign dams to make such sustainable
sediment management feasible.
File Size : 350,178 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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