A lesson in preparedness: Assessing the effectiveness of low-cost postwildfire flood protection measures for the catastrophic flood in Kineta, Greece

Climate change-driven wildfires, especially in the Mediterranean, are not only becoming more frequent and severe but also amplifying flood risks by altering catchment hydrology. Yet, post-fire flood risk management remains inadequately addressed. In response, we develop an integrated simulation framework that combines meteorological, hydrological, hydraulichydrodynamic models and remote sensing techniques to represent post-wildfire flood hazards and support the design of Postwildfire Flood Protection Treatments (PFPTs). We utilize the framework to accurately represent a post-wildfire flash flood event in a Mediterranean catchment in Greece. The flood event is simulated under three scenarios: pre-wildfire, post-wildfire without any PFPTs in place (reality), and post-wildfire with PFPTs. The results show that the wildfire's impact on flood extent was around a 24.1% increase, but the PFPTs could have counterbalanced this impact. Moreover, we present an economic model for estimating the cost of the recommended PFPTs and the flood damage direct costs, combining an accounting and a semiautomated AI-based approach. The cost comparison reveals that the protection would have cost around 3.45mill EUR (just the 13.7% of the flood damage costs, 25.2mill EUR) potentially saving 6.37mill EUR in flood damage. By filling critical knowledge gaps, our study offers insights into the dynamics of post-wildfire flood events and provides policymakers with valuable insights for timely risk mitigation amidst escalating fire-related disasters.