Réponse morphologique des chenaux alluviaux aux travaux d'entretien : le cas des chenaux secondaires végétalisés de la Loire moyenne

Morphological response of alluvial channels to maintenance operations: the case of the vegetated secondary channels of the River Loire

Equipe Pluridisciplinaire Plan Loire Grandeur Nature Agence de l’eau Loire – Bretagne Avenue de Buffon – BP 6339, 45063 Orléans Cedex 2

Auteur de correspondance : stephane.rodrigues@etu.univ-tours.fr

Abstract

During the ten last years, fluvial maintenance operations were carried out in order to restore flow capacity and to promote sediment reworking in the secondary vegetated channels of the Loire River (France). This paper describes the evolution of vegetation and sediment dynamics after management operations performed on a secondary channel located in the middle reaches of the Loire. Investigations done in the area of Bréhémont (790 km downstream of the source) have highlighted a rapid colonization of the channel by woody pioneer vegetation after the management works. These trees exert a strong influence on both flow and sediment dynamics. This paper suggests that multidisciplinary surveys should be done during and after the river management operations in order to increase our understanding of the response of the river to disturbances caused by fluvial maintenance works.