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Halvfari dam – hydraulic concerns and rebuilding for higher safety standard
Vattenfall R&D.
2007 (English)Conference paper (Refereed)
Abstract [en]

Halvfari is a 43 m high embankment dam. In its safety evaluations made in the light of the revised dam-safety guidelines, several safety issues have been identified. The major concerns are insufficient spillway discharge capacity, inadequate energy dissipation and risk for erosion in the right riverbank downstream of the dam. The updated design flood of the dam turned out to be some 50% higher than its exiting spillway capacity. Structural modifications are necessary to adapt the dam to a higher safety standard. Among a few potential measures, construction of a new bottom spillway, located below the existing free-drop spillway, is chosen to increase the discharge capacity. To guarantee satisfactory hydraulic behavior, physical model studies are made to help in re-shaping the waterway. Due to the large increase in the flood magnitude, energy dissipation has to function properly even at higher discharges. To reduce the flow velocity and wave motions in the channel downstream, modifications are made to the spillway structure. The spillway piers are extended downstream and deflectors are added to direct the floodwater into the plunge pool that unfortunately has a very limited volume. Tests of movable bed are also conducted for the right riverbank downstream to investigate the risk for erosion and verify potential engineering measures.

Place, publisher, year, edition, pages
2007.
Keyword [en]
Halvfari, dam safety, design flood, model study, discharge capacity, erosion, rebuilding
National Category
Civil Engineering
Identifiers
URN: urn:nbn:se:kth:diva-179783OAI: oai:DiVA.org:kth-179783DiVA: diva2:889448
Conference
Intl. Symposium Modern Technology of Dams, Oct 2007, Chengdu, China
Note

QC 20160107

Available from: 2015-12-25 Created: 2015-12-25 Last updated: 2016-01-07Bibliographically approved

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Yang, James
Civil Engineering

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