Vers une intégration des techniques spatiales pour la gestion des inondations

Correlation between hydro-meteorological variables and SAR backscattering coefficient is studied over the Alzette river basin (Luxembourg), using ERS-1 and 2 images. Direct relations between radar backscatter and other variables are first investigated. Then, using the PCA transformation, specific hydrological patterns of the alluvial plain are highlighted. And finally, a cross validation of radar flood extent mapping and hydraulic model results is performed using an areal approach. An instantaneous radar derived flood extent helps retrieving the regional conveyance factors in one-dimensional and two-dimensional hydraulic models and thus offers a more powerful calibration tool than local observations of water levels. The main idea is to establish a parameter retrieval strategy, enabling a better knowledge of the internal state data in distributed and semi-distributed hydrological models. This will become even more pertinent for non-equipped catchments.