Principes nouveaux en matière de gestion des marges de rivières en tresses (exemple de la moyenne vallée du Giffre, Haute-Savoie, France) / New principles relating to the management of braided streamways : example of the mid-Giffre valley in Haute Savoie, France

Abstract

Abstract : The importance of the streamway preservation concept is increasingly recognised by the managers of high-energy hydrosystems. The paper examines the eco-geographical, patrimonial and economic reasons for this new approach through a case study of the middle Giffre valley (Haute Savoie, France). Lateral instability of the channel is evaluated using a geomorphological analysis based on a GIS raster, the result providing useful input in the decision-making process. It is not the only consideration, however, in implementing the streamway preservation concept. The opinion of local actors such as floodplain forest owners, mayors and other government authorities must also be taken into account. Technical studies are essential in defining steamways and estimating potential channel instability, but if a river management project is to succeed, it must be supported by the local community and water authorities.