Abstract: This data shows the extent of land that might be flooded by the sea (coastal flooding) and the associated flood depths during a theoretical or ‘design’ flood event with an estimated probability of occurrence, rather than information for actual floods that have occurred in the past. This represents the worst case scenario as any flood defences potentially protecting the coastal floodplain are not taken into account. Flood event probabilities are referred to in terms of a percentage Annual Exceedance Probability, or ‘AEP’. This represents the probability of an event of this, or greater, severity occurring in any given year. These probabilities may also be expressed as the chance or odds (e.g. 200 to 1) of the event occurring in any given year. They are also commonly referred to in terms of a return period (e.g. the 200-year flood), although this period is not the length of time that will elapse between two such events occurring, as, although unlikely, two very severe events may occur within a short space of time. The following sets out the range of flood event probabilities for which coastal flood extent maps were developed, expressed in terms of Annual Exceedance Probability (AEP), and identifies their parallels under other forms of expression. 50% AEP can also be expressed as the 2 Year Return Period and as the 2:1 odds of occurrence in any given year. 20% AEP can also be expressed as the 5 Year Return Period and as the 5:1 odds of occurrence in any given year. 10% AEP can also be expressed as the 10 Year Return Period and as the 10:1 odds of occurrence in any given year. 5% AEP can also be expressed as the 20 Year Return Period and as the 20:1 odds of occurrence in any given year. 2% AEP can also be expressed as the 50 Year Return Period and as the 50:1 odds of occurrence in any given year. 1% AEP can also be expressed as the 100 Year Return Period and as the 100:1 odds of occurrence in any given year. 0.5% AEP can also be expressed as the 200 Year Return Period and as the 200:1 odds of occurrence in any given year. 0.1% AEP can also be expressed as the 1000 Year Return Period and as the 1000:1 odds of occurrence in any given year. The Present Day Scenario is also referred to as the Current Scenario. Present Day Scenario data was generated using methodologies based on historic flood data, without taking account of potential changes due to climate change. The potential effects of climate change have been separately modelled and reported on. Flooding from other sources may occur and areas that are not shown as being within a flood extent may therefore be at risk of flooding from other sources. The flood extent and depth maps are suitable for the assessment of flood risk at a strategic scale only, and should not be used to assess the flood hazard and risk associated with individual properties or point locations, or to replace a detailed flood risk assessment. Lineage: The National Coastal Flood Hazard Maps (NCFHM) 2021 are ‘predictive’ flood maps, as they provide predicted flood extent and depth information for a ‘design’ flood event that has an estimated probability of occurrence (e.g. the 0.5% AEP event), rather than information for floods that have occurred in the past. The maps have been produced at a strategic level to provide an overview of coastal flood hazard in Ireland, and minor or local features may not have been included in their preparation. A Digital Terrain Model (DTM) was used to generate the maps, which is a ‘bare-earth’ model of the ground surface with the digital removal of human-made and natural landscape features such as vegetation, buildings and bridges. This methodology can result in some of these human-made features, such as bridges and embankments, being shown within a flood extent, when in reality they do not flood. It should be noted that the flood extent maps indicate the predicted maximum extent of flooding, and flooding in some areas, such as near the edge of the floodplain area, might be very shallow. The predicted depth of flooding at a given location is indicated on the flood depth maps. The flood depth is displayed as a constant depth over grid squares with a 5m resolution, whereas in reality depths may vary within a given grid square. No post-processing of the flood extent and depth map datasets has been undertaken to remove small areas of flooding that are remote and isolated, small islands within the flooded area, etc. Local factors such as flood defence schemes, structures in or around river channels (e.g. bridges), buildings and other local influences, which might affect coastal flooding, have not been accounted for. Detailed explanations of the methods of derivation, data used, etc. is provided in the NCFHM 2021 Flood Mapping Methodology Report. Users of the maps should familiarise themselves fully with the contents of this report in advance of the use of the maps. Purpose: The data has been developed to inform a national assessment of flood risk that in turn will inform a review of the Preliminary Flood Risk Assessment required to comply with the requirements of the European Communities (Assessment and Management of Flood Risks) Regulations 2010 to 2015 (the “Regulations”) (implementing Directive 2007/60/EC) for the purposes of establishing a framework for the assessment and management of flood risks, aiming at the reduction of adverse consequences for human health, the environment, cultural heritage and economic activity associated with floods.

Abstract: This data shows the extent of land that might be flooded by the sea (coastal flooding) and the associated flood depths during a theoretical or ‘design’ flood event with an estimated probability of occurrence, rather than information for actual floods that have occurred in the past. This represents the worst case scenario as any flood defences potentially protecting the coastal floodplain are not taken into account. Flood event probabilities are referred to in terms of a percentage Annual Exceedance Probability, or ‘AEP’. This represents the probability of an event of this, or greater, severity occurring in any given year. These probabilities may also be expressed as the chance or odds (e.g. 200 to 1) of the event occurring in any given year. They are also commonly referred to in terms of a return period (e.g. the 200-year flood), although this period is not the length of time that will elapse between two such events occurring, as, although unlikely, two very severe events may occur within a short space of time. The following sets out the range of flood event probabilities for which coastal flood extent maps were developed, expressed in terms of Annual Exceedance Probability (AEP), and identifies their parallels under other forms of expression. 50% AEP can also be expressed as the 2 Year Return Period and as the 2:1 odds of occurrence in any given year. 20% AEP can also be expressed as the 5 Year Return Period and as the 5:1 odds of occurrence in any given year. 10% AEP can also be expressed as the 10 Year Return Period and as the 10:1 odds of occurrence in any given year. 5% AEP can also be expressed as the 20 Year Return Period and as the 20:1 odds of occurrence in any given year. 2% AEP can also be expressed as the 50 Year Return Period and as the 50:1 odds of occurrence in any given year. 1% AEP can also be expressed as the 100 Year Return Period and as the 100:1 odds of occurrence in any given year. 0.5% AEP can also be expressed as the 200 Year Return Period and as the 200:1 odds of occurrence in any given year. 0.1% AEP can also be expressed as the 1000 Year Return Period and as the 1000:1 odds of occurrence in any given year. The High++ End Future Scenario (H++EFS) maps represent a projected future scenario for the end of century (circa 2100) and include allowances for projected future changes in sea levels and glacial isostatic adjustment (GIA). The maps include an increase of 2000mm in sea levels above the current scenario estimations. An allowance of -0.5mm/year for GIA was included for the southern part of the national coastline only (Dublin to Galway and south of this). Flooding from other sources may occur and areas that are not shown as being within a flood extent may therefore be at risk of flooding from other sources. The flood extent and depth maps are suitable for the assessment of flood risk at a strategic scale only, and should not be used to assess the flood hazard and risk associated with individual properties or point locations, or to replace a detailed flood risk assessment. Lineage: The National Coastal Flood Hazard Maps (NCFHM) 2021 are ‘predictive’ flood maps, as they provide predicted flood extent and depth information for a ‘design’ flood event that has an estimated probability of occurrence (e.g. the 0.5% AEP event), rather than information for floods that have occurred in the past. The maps have been produced at a strategic level to provide an overview of coastal flood hazard in Ireland, and minor or local features may not have been included in their preparation. A Digital Terrain Model (DTM) was used to generate the maps, which is a ‘bare-earth’ model of the ground surface with the digital removal of human-made and natural landscape features such as vegetation, buildings and bridges. This methodology can result in some of these human-made features, such as bridges and embankments, being shown within a flood extent, when in reality they do not flood. It should be noted that the flood extent maps indicate the predicted maximum extent of flooding, and flooding in some areas, such as near the edge of the floodplain area, might be very shallow. The predicted depth of flooding at a given location is indicated on the flood depth maps. The flood depth is displayed as a constant depth over grid squares with a 5m resolution, whereas in reality depths may vary within a given grid square. No post-processing of the flood extent and depth map datasets has been undertaken to remove small areas of flooding that are remote and isolated, small islands within the flooded area, etc. Local factors such as flood defence schemes, structures in or around river channels (e.g. bridges), buildings and other local influences, which might affect coastal flooding, have not been accounted for. Detailed explanations of the methods of derivation, data used, etc. is provided in the NCFHM 2021 Flood Mapping Methodology Report. Users of the maps should familiarise themselves fully with the contents of this report in advance of the use of the maps. Purpose: The data has been developed to inform a national assessment of flood risk that in turn will inform a review of the Preliminary Flood Risk Assessment required to comply with the requirements of the European Communities (Assessment and Management of Flood Risks) Regulations 2010 to 2015 (the “Regulations”) (implementing Directive 2007/60/EC) for the purposes of establishing a framework for the assessment and management of flood risks, aiming at the reduction of adverse consequences for human health, the environment, cultural heritage and economic activity associated with floods.

Abstract: This dataset represents the baseline position of the coastline in 2000 in areas considered to be vulnerable to erosion.

Lineage: An erosion ‘baseline’ was derived from the visible vegetation line shown on the Ordnance Survey Ireland (OSi) year 2000 aerial photography, or where appropriate, the cliff top line, and this was used as the basis for generating the 2030 and 2050 erosion maps.

Purpose: This data provides information required to inform policy in the management of risks associated with coastal flooding and coastal erosion. This is particularly relevant for local authorities in relation to the proper planning and development of coastal areas. The Irish Coastal Protection Strategy Study (ICPSS) is a national study that was commissioned in 2003 with the objective of providing information to support decision making about how best to manage risks associated with coastal flooding and coastal erosion. The Study was completed in 2013 and provides strategic current scenario and future scenario (up to 2100) coastal flood hazard maps and strategic coastal erosion maps for the national coastline.

Introduction

The Strategic Flood Map (Rivers) map service is a multi layered predictive flood mapping product providing a strategic overview of areas across Northern Ireland that could be affected by river flooding. The Strategic Flood Map (Rivers) includes the following layers of information for both present day and climate change epochs: • Floods with a medium probability

Purpose of the data

The dataset has been designed to raise awareness among the public, Government Departments, local authorities and other organisations of the likelihood of river flooding, thus supporting a more proactive and co-operative approach to flood risk management. By being aware of the land estimated to be at risk of flooding, authorities can develop strategies to better manage flood risk through their planning, flood prevention, and emergency planning functions.

Data Coverage

All of Northern Ireland, with some limited coverage in Republic of Ireland in border areas.

Data Format

OGC (Open Geospatial Consortium) compliant Web Mapping Service in WGS 1984 projection, accessible via secure website (requires authentication by user specific username and password).

Data content

Strategic River Floodplain o Rivers (Modelled/Unmodelled) Strategic River Floodplain (Present Day) o Medium Probability Floods (1% AEP) Strategic River Floodplain (Climate Change 2030) o Medium Probability Floods (1% AEP)

AEP is Annual Exceedance Probability e.g. the 1% AEP flood extent shows areas of land with an annual probability of flooding of 1% (or 1 in 100 chance) in any year.

Companion Mapping Services

• Strategic Flood Map (Coastal) • Strategic Flood Map (Surface Water) • Historical Flood Map

Contains five Environment Agency Coastal Flood Boundaries: Extreme Sea Levels, Extreme Sea Levels Estuary, Gauge Data, Estuary Intervals and Surge Shapes. Full description has been given below for the Extreme Sea Levels layer and the Extreme Sea Levels Estuary layer. Links are provided to the remaining three layers. Extreme Sea levels:This metadata record is for AfA product AfA 010. Extreme Sea Level values is part of Coastal Design/Extreme Sea Levels,a GIS dataset and supporting information providing design / extreme sea level and typical surge information around the coastline of the UK, including England, Wales, Scotland, Northern Ireland, Isle of Man and Jersey. The information is relevant under present day (year 2018) conditions and does not account for future changes due to climate change, such as sea level rise. This is a specialist dataset which informs on work commenced around the coast ranging from coastal flood modelling, scheme design, strategic planning and flood risk assessments.Extreme Sea Level values describes the extreme sea levels for 16 different annual probabilities of exceedance. Confidence levels relating to the 5% and 95% lower and upper bounds of confidence are included. Mean High Water Spring (MHWS) and Highest Astronomical Tide (HAT) predicted tide levels are also included in the dataset for some sites but may not be used for navigational purposes.This 2018 update to the Coastal Design Sea Levels dataset was carried out in partnership for the UK Coastal Flood Forecasting partnership, which includes the Environment Agency (EA), Scottish Environment Protection Agency (SEPA), Natural Resources Wales (NRW) and the Department for Infrastructure Northern Ireland (DfINI).Extreme Sea Levels Estuary:This metadata record is for AfA product AfA 010. Extreme Sea Levels Estuary values is part of Coastal Design/Extreme Sea Levels,a GIS dataset and supporting information providing design / extreme sea level and typical surge information around the coastline of the UK, including England, Wales, Scotland, Northern Ireland, Isle of Man and Jersey. The information is relevant under present day (year 2018) conditions and does not account for future changes due to climate change, such as sea level rise. This is a specialist dataset which informs on work commenced around the coast ranging from coastal flood modelling, scheme design, strategic planning and flood risk assessments.Extreme Sea Level values describes the extreme sea levels for 16 different annual probabilities of exceedance. Confidence levels relating to the 5% and 95% lower and upper bounds of confidence are included. Mean High Water Spring (MHWS) and Highest Astronomical Tide (HAT) predicted tide levels are also included in the dataset for some sites but may not be used for navigational purposes. This dataset provides level this level information for sites in estuaries, tidal rivers and harbours. Levels for open coastal areas are provided separately in Extreme Sea Levels.This 2018 update to the Coastal Design Sea Levels dataset was carried out in partnership for the UK Coastal Flood Forecasting partnership, which includes the Environment Agency (EA), Scottish Environment Protection Agency (SEPA), Natural Resources Wales (NRW) and the Department for Infrastructure Northern Ireland (DfINI).Gauge Data: https://environment.data.gov.uk/arcgis/rest/services/EA/CoastalDesignSeaLevels/MapServer/2Surge Shape data: https://environment.data.gov.uk/arcgis/rest/services/EA/CoastalDesignSeaLevels/MapServer/4Estuary intervals: https://environment.data.gov.uk/arcgis/rest/services/EA/CoastalDesignSeaLevels/MapServer/3

Activation time (UTC): 2020-10-20 11:24:00
Event time (UTC): 2020-10-20 08:00:00
Event type: Flood (Coastal flood)

Activation reason:
Around 100 buildings and dozens of parked cars have been damaged by flooding in Cork city centre following high tide on 20th October 2020. Significant flooding has also been in County Cork following the high tide event.

Reference products: 0
Delineation products: 1
Grading products: 0

Copernicus Emergency Management Service - Mapping is a service funded by European Commission aimed at providing actors in the management of natural and man-made disasters, in particular Civil Protection Authorities and Humanitarian Aid actors, with mapping products based on satellite imagery.

Abstract: This dataset represents the future likely position of the coastline in 2050 in areas considered to be vulnerable to erosion. Lineage: A comparison of the best available current and historical mapping and aerial photography was used to estimate the annual rate of change in the coastline position and hence to predict the likely future position of the coastline in 2050. The rate of coastline change (annual erosion rate) for future years was assumed to be the same as in the past. An erosion ‘baseline’ was derived from the visible vegetation line shown on the Ordnance Survey Ireland (OSi) year 2000 aerial photography, or where appropriate, the cliff top line, and this was used as the basis for generating the 2050 erosion maps. The erosion maps have been produced for existing conditions only and do not include for projected future changes in climate such as sea level rise, increased storm frequency or associated variations in erosion rates. The ICPSS erosion hazard mapping is for strategic purposes, and minor or local features may not have been included in their preparation. Therefore, the maps should not be used to assess the erosion hazard and risk associated with individual properties or point locations, or to replace a detailed local erosion hazard and risk assessment. It was not possible to eliminate the effect of existing coastal defence structures from the erosion hazard and risk assessment. Consequently, there will be areas where no erosion line is shown that are at risk from erosion, should present defences fail or not be maintained in the future. Equally, there may be an erosion line shown in areas that are now adequately defended by coastal protection structure that were introduced during or after the assessment period. Purpose: This data provides information required to inform policy in the management of risks associated with coastal flooding and coastal erosion. This is particularly relevant for local authorities in relation to the proper planning and development of coastal areas. The Irish Coastal Protection Strategy Study (ICPSS) is a national study that was commissioned in 2003 with the objective of providing information to support decision making about how best to manage risks associated with coastal flooding and coastal erosion. The Study was completed in 2013 and provides strategic current scenario and future scenario (up to 2100) coastal flood hazard maps and strategic coastal erosion maps for the national coastline.