In extreme flood events (T > 1000), the land occupation in floodplains becomes a major issue as it highly influences the flow resistance and thus, the hydrodynamic processes. In this context, this study assesses, for increasing land occupations, the influence of the bed friction and that of the drag induced by emergent obstacles on the flow resistance. The study is based on laboratory experiments that were conducted at LMFA. In these experiments, the bed friction was generated by artificial grass with a roughness height of 5 mm, and the land occupation was modeled by prismatic obstacles (220x54x54 mm³) that were uniformly distributed throughout the flume. The measurements were performed under uniform flow conditions, and they consisted of : i) velocity measurements to characterize the hydrodynamics, and ii) measurements of the drag force that the flow exerted on an obstacle.
[Sebastián GUILLÉN LUDENA] est en Post-Doc à l’INSA.