This dataset provides an estimate of extreme water levels around the coast of Ireland for a range of Annual Exceedance Probabilities (AEPs). Extreme water level estimates are provided for present day sea levels as well as the Mid-Range Future Scenario (MRFS), High End Future Scenario (HEFS), High+ End Future Scenario (H+EFS) and High++ End Future Scenario (H++EFS) which represent a 0. 5m, 1.0m, 1.5m and 2.0m increase in sea level, respectively. 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 Mid-Range Future Scenario extents where generated taking in in the potential effects of climate change using a sea level rise of 500mm (20 inches). The High-End Future Scenario extents where generated taking in in the potential effects of climate change using a sea level rise of 1,000 mm (40 inches). The High-End+ Future Scenario extents where generated taking in in the potential effects of climate change using a sea level rise of 1,500 mm (60 inches). The High-End++ Future Scenario extents where generated taking in in the potential effects of climate change using a sea level rise of 2,000 mm (80 inches). 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 purpose of the Flood Maps is not to designate individual properties at risk of flooding. They are community-based maps.

Lineage: There are a number of limitations which should be considered when using this data for subsequent analysis. These include uncertainties in the derivation of the individual extreme values associated with topographic and other survey data uncertainties, inaccuracy in meteorological and offshore wave data, assumptions and / or approximations in the hydraulic / hydrodynamic models in representing physical reality, assumptions and / or approximations in the statistical analysis and uncertainties in datum conversions. Further uncertainty arises from the use of the FD2308 joint probability method in the absence of defined and agreed dependence values for waves and tidal levels around Ireland. Taking account of the study limitations, the estimated accuracy of the total water levels presented in this report is ±150mm. Users of this data should refer to the Irish Coastal Wave and Water Level Modelling Study 2018 Phase 1 Technical Report that can be found on https://www.floodinfo.ie/publications/.

Purpose: This data provides information required to inform policy in the management of risks associated with coastal flooding. This is particularly relevant for local authorities in relation to the proper planning and development of coastal areas. The Irish Coastal Wave and Water Level Modelling Study (ICWWS) 2018 is a national study that was commissioned in 2018 with the following objectives: 1. Update the estimated extreme water levels for all coastal boundary point locations, previously derived as part of the Irish Coastal Protection Strategy Study (ICPSS), around the coast of Ireland (Phase 1). 2. Update the estimated extreme coastal water level and wave climate joint probability information for all coastal areas potentially vulnerable to wave overtopping (CAPOs) identified in the previous ICWWS 2013 project (Phase 2). 3. Develop detailed coastal models of specified major coastal flood relief scheme locations (including Dundalk and Blackrock, Co. Louth; Carlingford, Co. Louth; Tralee, Co. Kerry; Shannon and Bunratty, Co. Clare) and provide joint probability water level and wave climate conditions for the present day and four future climate change scenarios, to facilitate the subsequent and necessary wave overtopping analysis and modelling to inform and confirm scheme design standard and hydraulic performance. This includes the incorporation of more detailed bathymetric information together with consideration and analysis of beach drawdown and wave set-up where relevant (Phase 3). 4. Review the existing available relationship (height difference) between current Mean Sea Level (MSL) and Ordnance Datum Malin (OD Malin) around the coast of Ireland and estimate an up to date relationship (with assigned confidence) at all suitable coastal gauge locations and develop and apply a methodology to interpolate the MSL to OD Malin relationship to non-gauged locations for both OD Malin (OSGM02 and OSGM15) datums (Phase 4).