Abstract
In order to modelling the interaction among plants, flow field and sediment transport in vegetated rivers, some simplifications are often necessary. Accordingly, bed forms in vegetated rivers are often not considered, neither in the determination of resistance, nor in the definition of sediment entrainment. The experimental approach proposed in this paper demonstrates that the formation of the bed forms and their geometry are strictly related with the density and distribution of the vegetation. The paper proposes a set of experimental results regarding the averaged length and height of bed forms in a laboratory vegetated channel.The experimental results highlight that the bed forms change their nature, passing from steady configuration to dunes downstream migrating, depending on the density of plants. Moreover, the bed forms geometry seems to be more related with the distribution of plants, rather than with the flow conditions as for the natural dunes.