Efficacité des barrières végétales pour la lutte contre l'envasement des retenues de barrages

Efficiency of vegetation barriers for reduction of silting behind hydroelectric dam impoundments

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Auteur de correspondance : freedy.rey@cemagref.fr

Abstract

Erosion in marly torrential catchments in the French Southern Alps causes silting of hydroelectric dam impoundments established along the Durance river. One solution to assist in solving this problem consists of retaining the sediments within the catchments. To do this, vegetation and bioengineering works can be used as efficient and sustainable means to avoid sediment erosion and transport to dam impoundments. Effectively, the cover provided by vegetation and bioengineering works acts as a barrier to soil erosion. The studies showed that vegetation barriers can stop sediment yield at the exit of gullies only partially covered with vegetation, if the vegetation is located downstream of the gully. This paper presents the current and improved knowledge about the influence of vegetation barriers on erosion, and explains how to use this knowledge to propose optimal strategies for reduction of the sediment load in rivers and hydroelectric dam impoundments, by the use of ecological engineering techniques.