A near real-time procedure for flood hazard mapping and risk assessment in Europe

Francesco Dottori, Peter Salamon, Milan Kalas, Alessandra Bianchi, Jutta Thielen, Luc Feyen

Wednesday 1 july 2015

9:30 - 9:45h at South America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flood risk assessment

Parallel session: 8J. Floodrisk - Assessment

The availability of a real-time operational system for mapping flood hazard and assessing potential consequences might be extremely useful to help emergency response and management and to mitigate the impact of large flood events. This work describes the development of an experimental procedure for rapid flood risk assessment within the European Flood Awareness System (EFAS), which since 2012 provides operational flood predictions for the major European rivers as part of the Copernicus Emergency Management Services. The hydro-meteorological data set available in EFAS is used to derive long-term streamflow simulations and design flood hydrographs in a wide number of locations, covering all the major European river network. Flood hydrographs are then used as input to a hydrodynamic 2D model to create a high-resolution dataset of areas at risk of flooding for different return periods. Whenever a flood event is forecasted in EFAS, the flood maps of the river network sections potentially involved are merged together, based on the estimated magnitude of the event. In order to take into account the different flood forecasts available in EFAS, different combinations of flood hazard maps may be produced, to highlight the possible range of uncertainty in predictions. The merged flood maps can be combined with the available spatial information about land use, population, urban areas and infrastructures, to assess the potential impact of the forecasted flood event in terms of economic damage, affected population, major infrastructures and cities. A preliminary version of the procedure has been successfully tested in reproducing flooded areas and impacts in the recent floods in Bosnia-Herzegovina, Croatia and Serbia. Moreover, the reduced computational times are compatible with near real-time applications, even in case of multiple flood events affecting several countries. Currently, the integration of the procedure within EFAS for operational use is being tested.