Flood Damage Assessment through multi-temporal COSMO-SkyMed data and Hydrodynamic Models: the Albania 2010 Case Study

Flood damage assessment needs not only the estimation of the flood extent, but also the information on the drainage of the floodplain and the dynamics of variables as water depth and velocity. These data might be gathered by exploiting numerical models of water propagation in floodplains, which enable to build flood scenarios in real time if reliable digital elevation models are available. However, a strong limitation for the application of numerical models could be the lack of information regarding the actual flood extent and the dynamics of flooding and receding phases, as well as the locations where water overflowed and the related flood volumes. Inundation extent can be estimated through Synthetic Aperture Radar (SAR) data and, by exploiting the short revisit time of the images provided by the COSMO-SkyMed (CSK) constellation of four satellites, it is possible to monitor also the dynamics of the flood extent. Hence, it comes out the need of a combined use of multi-temporal SAR data and numerical models for the purpose of a reliable flood damage assessment. This paper presents the major outcomes of a combined use of a multi-temporal series of CSK observations and a hydrodynamic model aiming at the evaluation of damage scenarios for the flood that hit Albania on January 2010. It is shown that by adjusting the outputs of the model to match the flood extent observed by SAR, the hydrodynamic inconsistencies in CSK estimates can be corrected and a reliable assessment of water depth and water velocities can be accomplished.