Managing the risk of flooding

Flooding is a natural phenomenon and has a devastating impact on communities. It cannot be entirely prevented but by working together we can plan to effectively manage the risk.

The effects of flooding are wide ranging, impacting on the economy, social wellbeing and the environment.

For individuals and communities the impact can be significant in terms of personal suffering and financial loss and, even where flooding has natural causes, it can have damaging effects on the environment.

Essential services such as mains water, electricity and transport can be disrupted. Property and possessions can be damaged and most seriously, flooding can result in injury and death.

Under the Floods Directive we manage these risks by:

  • prevention: avoiding construction of houses and industries in flood-prone areas; by adapting future developments to the risk of flooding; and by promoting appropriate land-use, agricultural and forestry practices
  • protection: taking measures, both structural and non-structural, to reduce the likelihood and impact of floods
  • preparedness: informing the public about flood risk and what to do in the event of a flood

To achieve its objectives, the Directive will address flood risk in Northern Ireland on a catchment-wide scale. This is because flooding problems may be affected by the characteristics of the catchment.

A catchment is an area drained, either naturally or with artificial assistance, by a watercourse, including all drainage channels, tributaries, floodplains, estuaries and areas of water storage.

The Floods Directive requires consideration of flooding by sea, rivers and lakes, surface water and reservoirs. By assessing the ‘bigger picture’ we can ensure that the flood risk is fully understood which will help us make sustainable, long term decisions.

Flood risk management, through the Floods Directive, takes place alongside the ongoing delivery of a prioritised government programme of drainage and flood alleviation measures.

DfI Rivers also aims to reduce the risk to life and damage to property from flooding from rivers and the sea through, amongst other activities, providing expert flood risk advice to local planning authorities, undertaking sustainable watercourse maintenance, controlling, as far as weather conditions permit, Lough Neagh & Lough Erne water levels, constructing new and maintaining existing flood defences, fulfilling a key role in the emergency response to flooding incidents and working to enhance Community Resilience in areas subject to flood risk or severe weather

The Directive Timeline is geared to a rolling cycle so its 3 key stages must be repeated on a cyclical basis (every 6 years) to ensure that flood risk is managed effectively and that it takes account of new information and changes in risk. Further information on the key stages can be found via the link below: 

The Northern Ireland legislation to enable the Directive was introduced in 2009 and is called The Water Environment (Floods Directive) Regulations (Northern Ireland) 2009. The legislation requires the element of the 2nd cycle to be completed by the following dates:

  • Northern Ireland Flood Risk Assessment – December 2018.
  • Review of flood risk and flood hazard maps for Areas of Potential Significant Flood Risk – December 2019.
  • Flood Risk Management Plan – December 2021. The plan will set out our objectives, measures and for managing the risk of flooding.

Information on the 1st cycle can be found via the link below:

Areas of Potential Significant Flood Risk

The Northern Ireland Flood Risk Assessment (NIFRA) 2018, completed in December 2018, is a high level analysis of the potential economic, social and environmental impacts which could result from flooding in Northern Ireland. Based on the NIFRA 2018, the areas assessed to be at the greatest flood risk have been identified. These areas are designated as ‘Areas of Potential Significant Flood Risk’ (APSFR) In addition, the Department has determined some areas to be Transitional Areas of Potential Significant Flood Risk (TAPSFR). These are areas that were identified in the 2011 PFRA as APSFR. They have not been identified as APSFR in the NIFRA 2018. However, they have been classified as TAPSFR to ensure continuity between Flood Risk Management Plan cycles and facilitate the implementation of any outstanding commitments arising from delivery of objectives and measures within the 2015 – 2021 FRMPs. Both APSFR and TAPSFR are detailed in the map and table below. This is a critical milestone in the implementation of the EU Directive as it identifies the areas for which we are required to produce flood risk management plans.

Flood risk is a measure of the statistical probability that flooding will occur combined with the adverse consequences of the flooding. The assessment of future flood risk therefore requires a detailed understanding of the flood mechanisms for each source of flooding, the magnitude and statistical probability of flood events and the scale of the potential adverse consequences arising from these events.

The extent of the potential future flood hazards for each source of flooding for a range of return periods was determined using predictive flood inundation models developed by DfI Rivers for rivers, sea and surface water. Although strategic in nature these models have been developed using best practice methodologies that utilise the available topographical and land use data.

For each area we have provided details of the flood source and the impact it could potentially have on the people, places, infrastructure and activities in that area.

APSFR and TAPSFR in the Neagh Bann River Basin District

Newry Banbridge
Lurgan Antrim
Glengormley and Mallusk Coleraine
Portadown and Craigavon Warrenpoint

APSFR and TAPSFR in the North East River Basin District

Belfast Dundonald
Larne Newtownards
Bangor Newcastle
Newtownabbey Downpatrick

APSFR and TAPSFR in the North West River Basin District

Londonderry Strabane

The NIFRA 2018 report contains a narrative which describes the adverse consequences of major floods which occurred in the past but also focuses on the quantification and measurement of the potential adverse consequences of floods that may occur in the future.

Flood Maps (NI)

Flood Maps (NI) shows the areas in Northern Ireland that have flooded from rivers, the sea and surface water in the past and those which may be prone to flooding now and in the future. It also shows where existing flood defences are located and highlights the areas that benefit from these.

Please note, the map illustrates a national assessment of flood prone areas from various flood sources but may not be sufficiently accurate to determine the flood risk to individual properties or specific point locations. Please also note that it currently does not illustrate flooding from sources such as reservoirs.

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