A new framework for flood damage assessment considering the within-event time evolution of hazard, exposure, and vulnerability

Commonly adopted procedures for flood damage assessment are based on functions of the hazard that depend on the item under investigation (e.g., an area, a building), and on the vulnerability of exposed items. Available flood damage models make use of summary indicators, usually correspondent to the worst conditions expected during the flood event (e.g., the maximum flooded area, the envelop of maximum water depths, the maximum presence of people in the area, etc.), which cannot properly describe the time evolution of hazard and exposure during the flood event. This is an important limitation, as the flood damage also depends on how the involved processes evolve in time. In the present work, we propose a new framework for the assessment of flood damage that considers how damage evolves in time within a single flood event. The goal is achieved by computing flood damage by integrating over time the rate at which damage progresses, which in turn depends on time-varying hydraulic conditions and exposure. Application to schematic, yet realistic, examples shows the effectiveness of the method and its potential in flood risk assessment and management.