L’(in)efficacité géomorphologique des cascades sédimentaires en question : les apports d’une analyse réseau

Abstract

The formalization of sediments cascades within a catchment is one of the main field research in geomorphology. Since the pioneering studies on geomorphic open systems, inefficient sediment exportation at catchment sinks has been widely observed. The complexity of sediment fluxes patterns is also enhanced. Well defined in concepts such as the sediment delivery problem or sedimentological anarchy, these observations are however only partially understood. After a brief synthesis of previous works led on sediment cascades, we propose in this paper to consider sediment cascades as a network. Such networks are described through graph theory and simulation tools. These methods are applied to explore how sedimentary cascades work, especially by evaluating a net contribution of the network to the volume flow. Applied to an alpine watershed, these methods show that the connectivity properties of sediments cascades can explain their structural inefficiency to export sediments.

Keywords

• watershed
• flows
• network
• connectivity
• graph theory
• geomorphology