La situation de 1856 est elle reproductible ? Le cas du grand Lyon, à la confluence du Rhône et de la Saône

The case of the Lyon urban community, at the confluence of Rhône and Saône

Service Navigation Rhône-Saône, 2, rue de la Quarantaine, 69312 Lyon Cedex 05

Auteur de correspondance : Yves.Picoche@equipement.gouv.fr

Abstract

The 1856 flood was one of the most tremendous cataclysms ever to have plagued the French river banks. It caused major damages in Lyon and its vicinity, mainly because the Tête d’Or dikes were swept.Since 2002, studies of the Rhône and Saone rivers have been made on the Lyon urban community area: they show that in the event of a major flood (similar or superior to that of 1856), the flooded areas would now be much less important, due to the civil engineering works made since 1856. But many dwelling houses, plants or commercial premises were built since then, which would nowadays lead to tremendous damages: those are estimated (for the Lyon urban community) at one billion euros for a centennial flood, not even taking into account the consequences of ground water rise and of sewerage systems overflowing that would no doubt occur in such a situation, and would be even more costly.