Articles | Volume 17, issue 7
https://doi.org/10.5194/nhess-17-1111-2017
https://doi.org/10.5194/nhess-17-1111-2017
Research article
 | 
11 Jul 2017
Research article |  | 11 Jul 2017

An operational procedure for rapid flood risk assessment in Europe

Francesco Dottori, Milan Kalas, Peter Salamon, Alessandra Bianchi, Lorenzo Alfieri, and Luc Feyen

Abstract. The development of methods for rapid flood mapping and risk assessment is a key step to increase the usefulness of flood early warning systems and is crucial for effective emergency response and flood impact mitigation. Currently, flood early warning systems rarely include real-time components to assess potential impacts generated by forecasted flood events. To overcome this limitation, this study describes the benchmarking of an operational procedure for rapid flood risk assessment based on predictions issued by the European Flood Awareness System (EFAS). Daily streamflow forecasts produced for major European river networks are translated into event-based flood hazard maps using a large map catalogue derived from high-resolution hydrodynamic simulations. Flood hazard maps are then combined with exposure and vulnerability information, and the impacts of the forecasted flood events are evaluated in terms of flood-prone areas, economic damage and affected population, infrastructures and cities.

An extensive testing of the operational procedure has been carried out by analysing the catastrophic floods of May 2014 in Bosnia–Herzegovina, Croatia and Serbia. The reliability of the flood mapping methodology is tested against satellite-based and report-based flood extent data, while modelled estimates of economic damage and affected population are compared against ground-based estimations. Finally, we evaluate the skill of risk estimates derived from EFAS flood forecasts with different lead times and combinations of probabilistic forecasts. Results highlight the potential of the real-time operational procedure in helping emergency response and management.

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Short summary
We present a method to use river flow forecasts to estimate the impacts of flood events in terms of flood-prone areas, economic damage, cities and population at risk. We tested our method by simulating the catastrophic floods occurred in May 2014 in Southern Europe. Comparison with observed data shows that our simulations can predict flooded areas and flood impacts well in advance. The method is now being used for real-time risk forecasts to help emergency response and management.
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