2nd Cycle - Flood Hazard and Flood Risk Maps

Flood Risk maps show the possible consequences associated with each flood scenario.

These focus on the potential effects that the floods could have on the four flood risk classifications.

  • human health
  • economic activity
  • cultural heritage
  • the environment

In particular, the maps show the number of people and the types of economic activity affected, and highlight the location of potentially polluting installations that may adversely impact on environmentally sensitive sites.

Flood maps were first published by DfI Rivers in November 2008.

This first generation of maps, known as the Strategic Flood Map (NI) Rivers & Sea, was developed to provide an indication of the general areas throughout Northern Ireland that may be prone to flooding from rivers and the sea.

A strategic surface water flood map was subsequently published in December 2011 and the name of the map service was changed to the Strategic Flood Map (NI).

Due to the onerous requirement to produce flood maps that cover the whole of the province, it was necessary to develop the strategic flood models using a broad-scale modelling methodology that had clear limitations.

These limitations meant the estimated floodplain outlines and inundation areas produced using the strategic models were not considered to be sufficiently accurate to determine the flood risk to a particular property or specific point location.

However, the initial objective of the strategic maps was to highlight the general areas and communities that were potentially at risk of flooding and they were entirely suitable for this purpose.

The Strategic Flood Map was used in the Preliminary Flood Risk Assessment for NI (PFRA) which was completed in December 2011 in compliance with the EU Floods Directive.  A key objective of the PFRA was to identify areas of potentially significant flood risk for which detailed flood maps would be produced. On the basis of the PFRA, it was determined that detailed flood maps should be produced for 20 Significant Flood Risk Areas and 49 Areas for Further Study and this work was completed as required by the EU Directive in December 2013.

In comparison with the strategic flood maps the accuracy and scope of the information illustrated in the detailed maps is greatly improved and most importantly (unlike the strategic maps) is considered suitable for determining the level of risk to individual properties and specific point locations.

The detailed maps for the 69 areas are now hosted within Flood Maps (NI).

For the geographical areas that are not covered by the detailed mapping the strategic flood maps will continue to be displayed within Flood Maps (NI).

Following a review of the 2011 PFRA, the Northern Ireland Flood Risk Assessment 2018 identified a total of 45 flood risk areas. Out of these, 12 have been identified as Areas of Potential Significant Flood Risk (APSFR) and a further 9 determined as Transitional Areas of Potential Significant Flood Risk (TAPSFR) to ensure continuity between the 1st and 2nd Cycle Flood Risk Management Plans and to facilitate the implementation of any outstanding commitments arising from the delivery of the objectives and measures within the 2015 – 2021 Flood Risk Management Plans.

Although the updating of flood mapping is normally an on-going process, for each of the APSFR identified, the Regulations require that flood hazard and flood risk maps are reviewed and, if necessary, updated and made available to the public by 22 December 2019.  This exercise has been completed and the updated flood maps can be viewed at: https://www.infrastructure-ni.gov.uk/topics/rivers-and-flooding/flood-maps-ni

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