Floating Debris and Dam Safety: Hydraulic Model Tests

This volume marks one of a series of reports on the subject of the impact and mitigation of debrisas it affects hydro-electric dams during flood events.
Blockage of spillway capacity is a threat to dam safety all over the world; in some countries, this is a more common concern, and in other countries, it can lead to secondary effects such as major floods.Work with debris and dam safety has been performed in countries like Canada, Sweden, and Norway, but also in other countries. No general solution has been found, and one might never be found, as each dam and spillway is unique, and the solution for protecting the dam and spillway will differ from site to site.However, a need to better understand the debris problem and to find ways to improve the situation resulted in an international project initiated by the CEATI Dam Safety Interest Group (DSIG) on debris management in spillways and waterways. A report summarizing existing knowledge and giving a basis for the current work was published in 2005, entitled "Debris in Reservoirs and Rivers - Dam Safety Aspects".
In 2006, the DSIG project "Debris Management in Spillways and Waterways during Floods" was started, including four subprojects, namely:(a) Debris Yield Reduction By Management,(b) Evaluation of Failure Modes of Debris Booms,(c) Behaviour of Debris Booms Under Dynamic Loads,and (d) Debris at Spillways: Hydraulic Model TestsThis report addresses the fourth part of the work only, the objective of which was to increase the knowledge of the behaviour of floating debris in interaction with spillway structures, bridges, gates, log booms and the probability of safe passage through spillway openings. This work investigated the spillway capacity reduction or increase in water level during a debris blockage and also looked at countermeasures like the incorporation of a visor in front of the spillway.