This is a translation of the original Energiforsk report in Swedish (Report 2017:446).
A methodology has been developed that can be used to analyse and categorise dam facilities in terms of their vulnerability to floating debris and provide guidance on prioritisation and choice of any remedial action. The methodology presented consists of the assessment of three main components:
- Potential for formation of floating debris
Trees and shrubs, driftwood, beaver dams, sink logs, floating peat, jetties, boats, other structures and silage bales are all types of floating debris. The main reasons floating debris end up in the water are erosion, landslides and rockfalls, flooding, and high floods and water velocities that carry objects already in or adjacent to the body of water.
- Potential for transport of floating debris to the facility
This depends mainly on water velocities.
- Potential for floating debris to get stuck in the spillway opening and subsequently drawn down to the spillway’s threshold
Depends on the width of the spillway compared to tree lengths as well as the Froude number directly upstream the spillway.