Méthodologie d’estimation de paramètres en hydraulique fluviale, à partir d’extensions de zones inondées

Parameter estimation methodology using inundation extents in fluvial hydraulics

Institut de Mécanique des Fluides de Toulouse, Groupe HydroEco Allée du Professeur Camille Soula, 31400 Toulouse, France

Auteur de correspondance : roux@imft.fr

Abstract

Since its beginnings, remote sensing has considerably contributed to the progress of the researches in the field of flood hydrodynamic. The new generations of satellite are equipped with sensors of metric resolution. Therefore, they are now able to provide observations that need to be valorized as a new data source for hydraulic modeling. Indeed, some parameters embedded in open channel flow equations are difficult to calibrate in practice and hydraulic models are currently constrained by lack of data. The objective of this study is to test the potential of remote sensing imagery which may be used together with data assimilation methods to ascertain the value of a set of open-channel model parameters. The innovation of this study is to reconstitute information about the geometry of the river from top sight. Several data assimilation techniques have been tested on a synthetic case in order to find the most appropriate method for hydraulic parameter identification. The chosen optimization technique has then been implemented on two test sites. The study proceeds with an assessment of model performance when model calibrations are transferred between two flood events. Finally, a sensitivity analysis is carried out, together with an estimation of predictive uncertainty.