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. The land-use map was provided by GAF AG and recoded to pre-defined categories to ensure consistent results.
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 code 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.