Reservoir sedimentation: different type of flushing - friendly flushing example of genissiat dam flushing
Résumé
CNR (Compagnie Nationale du Rhone) France, has built and operates 18 multipurpose developments (one dam: Genissiat Dam and 17 Run of the River) along the Rhone River, France. IRSTEA (Institut national de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture) is a famous French Research Centre (previous name was CEMAGREF) and is specialised in water resources. Both companies have been working in close collaboration for years in hydrology and sediment management. Reservoir flushing is becoming a very important and complicated worldwide issue. On the one hand, water resources demand increases with growing world population, while the capacity of reservoirs decreases because of sedimentation. So flushing is necessary to maintain the reservoirs at the best operating capacity. In some countries, reservoir flushing is regulated and mandatory i.e. European Directives requiring sufficient sediment transport downstream of the dams. On the other hand, reservoir flushing must be organized in order to respect the environmental constraints downstream of the dams, regarding the concentrations of fine sediments. ‘Environmental friendly flushing’, to send only solid concentration that environment can withstand, is required today, while ‘hard flushing’ to send as much sediment as possible, resulting in probable damages to environment, is not sustainable and must be avoided. Friendly Flushing of Genissiat dam, organised by CNR every 3 years for the past 40 years on the Upper Rhone River, is taken as example. Physical phenomena regarding sediment transport during flushing are emphasized, both in the reservoir and downstream of the dam. A particular focus is made on the 1D mobile bed model RubarBE, developed by IRSTEA, which has significant interest for the understanding of flushing dynamics.
Domaines
Sciences de l'environnement
Origine : Fichiers produits par l'(les) auteur(s)
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