Roles of the riparian vegetation: the antagonism between flooding risk and the protection of environments

Since the beginning of the 20th century, man has domesticated his environment and caused the modification of hydraulic conditions during floods. In parallel, civil engineering has strongly progressed in the domain of hydraulic structures but especially the construction of dams and dikes has also massively increased and part of the population has lost the culture of risk by thinking they were completely out of danger from flooding. Events of hydrometeorological origin over the last 25 years has reminded man that the hydraulic infrastructures in place for a few centuries now, are not unalterable. An unmanaged vegetal colonization along the edge of watercourses (protection dikes, retention dams, appointed river banks, ect…) can present three types of inconvenience as (i) overflow in the case of watercourse containment, (ii) formation of woody jams which generate a risk of bridge obstructions or water retention, (iii) the presence of trees and their roots which damages the containment systems protecting the territories. It is important to manage the development of this vegetation in order to conserve the positive effects on the area while also limiting the negative impacts. The current boom in vegetation engineering techniques shows that man is relearning how to live as a ‘team” with nature

Gestion de la végétation sur digue : comment concilier GEMA et PI

Management of aquatic environments and flood prevention are not always compatible, especially when dealing with the complex issue of vegetation on flood protection works, such as dikes. The integration of GEMAPI with dykes must then be assessed on a case-by-case basis, depending on the condition of the structures and the protection issues. This article proposes some ways to reconcile civil engineering and ecological engineering, with an exemplary case study of taking into account aspects of GEMA (management of aquatic environments) and PI (protection of floods) on the dikes of the Leysse in Chambéry.Gestion des milieux aquatiques et prévention des inondations ne sont pas toujours compatibles, notamment quand on aborde la question complexe de la végétation sur les ouvrages de protection des crues, tels que les digues. L’intégration de la GEMAPI à des linéaires de digues doit alors être évaluée au cas par cas, en fonction de l’état des ouvrages et des enjeux de protection. Cet article propose quelques pistes pour concilier génie civil et génie écologique, avec un cas d’étude exemplaire de prise en compte des aspects GEMA (gestion des milieux aquatiques) et PI (protection des inondations) sur les digues de la Leysse à Chambéry

Toulouse dykes: reducing failure hazard combining structural reinforcement works and organization measures

Toulouse dykes include 16 km of various types of dykes and flood gates and stoplogs, belonging to several owners including Toulouse City and French State (DDT31) that own about 13 km. The Toulouse dykes Hazard Study has been made in 2014-2015. The study includes:

Toulouse dykes: reducing failure hazard combining structural reinforcement works and organization measures

Toulouse dykes include 16 km of various types of dykes and flood gates and stoplogs, belonging to several owners including Toulouse City and French State (DDT31) that own about 13 km. The Toulouse dykes Hazard Study has been made in 2014-2015. The study includes: