River Loire levees hazard studies – CARDigues’ model principles and utilization examples on Blois levees

¹ CEREMA, Direction Territoriale Normandie-Centre, Laboratoire Régional de Blois, 11 rue Laplace, 41029 Blois Cedex, France
² DREAL Centre-Val de Loire, 5 avenue Buffon, CS96407, 45064 Orléans cedex 2, France
³ DDT45, faubourg Bannier, 45000 Orléans, France

^a Corresponding author: Edouard.durand@cerema.fr

Abstract

Along the river Loire, in order to have a homogenous method to do specific risk assessment studies, a new model named CARDigues (for Levee Breach Hazard Calculation) was developed in a partnership with DREAL Centre-Val de Loire (owner of levees), Cerema and Irstea. This model enables to approach the probability of failure on every levee sections and to integrate and cross different “stability” parameters such topography and included structures, geology and material geotechnical characteristics, hydraulic loads… and observations of visual inspections or instrumentation results considered as disorders (seepage, burrowing animals, vegetation, pipes, etc.). This model and integrated tool CARDigues enables to check for each levee section, the probability of appearance and rupture of five breaching scenarios initiated by: overflowing, internal erosion, slope instability, external erosion and uplift. It has been recently updated and has been applied on several levee systems by different contractors. The article presents the CARDigues model principles and its recent developments (version V28.00) with examples on river Loire and how it is currently used for a relevant and global levee system diagnosis and assessment. Levee reinforcement or improvement management is also a perspective of applications for this model CARDigues.