Risk Maps - Trans-national

Officially risk is defined as the probability times the consequence. All experts agree on this definition. Nevertheless, in practise the term flood risk is often used differently.

The table shows one of the definitions of Flood risk used in the UK.

In Sweden, the General Flood Risk map, only contains information on the probability of inundation and does not give any information on the consequence. The combination of probability of flood and the consequence is not yet mapped in Sweden and Norway.

By mapping only water depth, the inundation area and total damage, no decision support for flood resilience related planning is prepared: when risk maps are presented in public, a clear plain risk zoning is necessary.

Therefore, risk maps in the Netherlands, Germany and the UK often include the consequences of flood events in monetary values in combination with the return period as weighting factor and offer decision makers in this way a basis for sustainable planning.

In the UK the National Flood Risk Assessment (NaFRA) map shows the flood risk (probability of flood, combined with the probability of defence failure and socio-economic consequences of the resulting flood). Further, on a more regional scale, the Strategic Flood Risk Assessment map (SFRA) presents for a region (borough or district) actual flood risk and generally identifying a zone of rapid inundation. The Flood Map is subdivided to show areas which are at significant, moderate and low risk of flooding.

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Flood risk mapping






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