La dynamique fluviale à l'épreuve des changements environnementaux : Quels enseignements applicables à l'aménagement des rivières ?

River dynamics resistant to environmental changes: What lessons can be learned from river developments?

Département de Géographie, Université Lyon III, URA 260 du CNRS et PIREN Vallées Fluviales

Abstract

Active rivers of France have been managed follolwing the implicit hypothesis that fonctionning is stable on the long term. In fact, the major choices of management have been settled during the XIXth century, i.e. at the end of the so-called "Little Ice Age", a period which was caracterized by large floods and by a high rate of bedload transportation; the policy of Mountain Conservation, the river training schemes and the extraction of gravels have desequilibrated the fonctionning of many rivers which are presently endangered by a deficit of bedload. The maintenance of processes of coarse supply into rivers, the cessation of extractions and the restoration of mobile gravel beds are recommanded.