Risk is defined as a combination of probability and consequences. A detailed and uniform land-use map is an important prerequisite to perform flood risk calculations, since it determines what is damaged in case of flooding.
Two different datasets regarding the urban landuse were made available:
• LULC product based on VHR data (WorldView-4 acquired on 29/11/2018) covering the core urban area (approx. 89,0 km²)
• LULC product based on HR data (Sentinel 2 acquired on 09/12/2018) covering the urban area (approx. 298,8 km²)
Both land-use classification results were recoded to pre-defined categories) and merged after categorization.
The exposition is classified integrating economic costs, social damage, physical damage and flood duration. Four land use damage levels (A, B, C, D) are defined based on this estimation.
The Flood Risk matrix is generated based on these results and on flood hazard classified into three hazard levels. The flood risk level is classified in four qualitative classes based on the combination of flood hazard and land use damage.