Drop structure applications in open channels: a case study

Abstract

The Downstream Channel is a 27km diversion channel to convey discharge from the new Nam Theun II hydropower project to the Xe Bang Fai River. The design of this channel required a careful balance of hydraulics, operational requirements, geological constraints, and economics. A range of river training techniques, including riprap protection and velocity control weirs, have been employed to manage scour in the channel, allowing the alignment and geometry of the channel to be optimised. Reservoirs can significantly alter the level of dissolved gases (eg oxygen, nitrogen, methane) present in the discharge waters, and can have a detrimental impact on aquatic life downstream. An aeration weir is to be constructed in the Downstream Channel to help equilibrate the dissolved gas levels in the discharge

Keywords:

• Weir
• drop structure
• river training
• water aeration
• oxygenation

Additional information

Notes on contributors

L Toombes

Luke Toombes received a Bachelor of Engineering degree from the University of Queensland in 1994. Upon graduation, he worked as an engineer for Cullen, Grummitt & Roe. Between 1996 and 2001 he undertook Ph.D. studies at the University of Queensland, researching water aeration on stepped cascades, and briefly worked at the university as an associate lecturer in 2001. Luke returned to the industry upon completing his Ph.D. and is currently a senior engineer in the Water and Environment Group of Connell Wagner.