Several parts of Europe, notably Italy, France, Ireland and Great Britain, are currently facing floods following the heavy rains that started in December. In order to improve the management of such events, mapping is needed of where floods can occur under certain circumstances. In a recent article the JRC, together with the European Centre for Medium-Range Weather forecasts and the University of Bristol, presented a new pan-European flood hazard map, the first of its kind at 100-metre resolution. Flood hazard maps at river-basin scale are needed to improve flood risk management.
Rome and the Italian islands have been hit by extensive flooding and landslides. Most of Ireland, the south-west of England and the Midlands are still under red alert for floods due to the high tides, heavy rain and strong wind, as is France's Atlantic coast and especially the Finistère department in the west.
EU Member States are currently undertaking significant efforts to generate high-resolution flood hazard and risk maps as required by the EU Floods Directive. Although the directive requires maps for trans-national river basins to be consistent, flood hazard maps for different river basins are often generated using different approaches and underlying data which leads to a lack of consistency.
For the new pan-European flood hazard map, the scientists used a combination of distributed hydrological and hydraulic models. This allowed them to derive flood hydrographs for a return period (average recurrence interval of flood events) of 100 years along the pan-European river network, which were then used to simulate areas at risk of flooding.
The quality of the pan-European flood hazard map has been evaluated for selected areas against national and regional hazard maps. Results showed a good agreement with the reference maps, highlighting the potential of the new map.
The space-/time-resolution or modelling could still be fine-tuned, for instance to better reproduce flood events in very small river basins. Additional return periods could also be considered.