Blockage of Reservoir Outlet Structures by Floating Debris / Blocage des Évacuateurs de Crue, Prises d'Eau et Vidanges de Fond par les Corps Flottants (Icold Bulletins Series)

The production of this Bulletin is a joint effort by the Committees on Hydraulics for Dams and on Dams and Floods to pool resources in producing an overview of the state of the art, latest research and industry developments relating to the subject of blockage of spillways, intakes and bottom outlets by floating debris. The topic is of common interest to both committees as the risks involved can be significant, potentially leading to partial or complete loss of hydraulic functionality or even to dam failure with far reaching public safety and economic consequences. A number of previous bulletins have addressed some of these issues in a range of different ways as outlined in the following paragraphs but none of them was specifically dedicated to this rather complex subject. This Bulletin therefore aims to fill this gap by further improving the awareness of the impact of blockage by floating debris on the economy and safety of reservoir projects and by providing practical guidance on the evaluation and management of the risk of blockage. In particular, it updates the topic by dealing in further detail with the relevant processes within the catchment, in the river basin and through the reservoir, while discussing the various methods and best practice techniques for floating debris characterisation and measures for blockage mitigation. In addition, the Bulletin discusses the uncertainties and residual risks associated with the current practices of dealing with floating debris and highlights areas where further research and development would be required. La production de ce Bulletin est un effort conjoint des Comités sur l'Hydraulique des Barrages et sur les Barrages et les Inondations pour mettre en commun les ressources afin de produire une vue d'ensemble de l'état de l'art, des dernières recherches et des développements industriels relatifs au sujet du blocage des évacuateurs de crue, des prises d'eau et des vidanges de fond par des débris flottants. Le sujet est d'int