Les sédiments dans les torrents de l'Arve : discontinuité fonctionnelle et impacts de l'aménagement des bassins versants

Sediments in the Arve torrents: functional discontinuities and impacts of improvement works on watersheds

Département de Géographie, Université Lyon 3, 74 rue Pasteur, 69239 Lyon Cedex

Abstract

The sediment dynamics on torrents are marked by functional discontinuities: firstly, a long period of sedimentary accumulation in the channel; secondly, a brief period of sedimentary expulsion during density flows, which carry out large volumes of debris and change strongly the channel geomorphology. Since the end of the 19th century, man has attempted to control the frequency and the intensity of sedimentary transportation by improvement works on slopes and in the channel; they have favoured the retention of the load in the mountain and have diminished the frequency of debris flows.