Northern Ireland Flood Risk Assessment (NIFRA) 2018 DECEMBER 2018 Northern Ireland Flood Risk Assessment Plan (NIFRA) 2018 2 Acknowledgements This report was prepared by RPS Consulting Engineers for Water and Drainage Policy Division (WDPD) of the Department for Infrastructure (DfI). Some of the data was derived and provided by DfI Rivers. Revisions Date Revisions Made May 2019 Correction of minor typographical errors Northern Ireland Flood Risk Assessment Plan (NIFRA) 2018 3 Contents Executive Summary ................................................................................................................................................................................................................................................................................................................... .8 1 Introduction ...........................................................................................................................................................................................................................................................................................................................................................9 1.1 Aims and Objectives ......................................................................................................................................................................................................................................................................................9 1.2 Scope .....................................................................................................................................................................................................................................................................................................................................................................9 1.3 Approach .............................................................................................................................................................................................................................................................................................................................................10 2 Flooding in Northern Ireland ........................................................................................................................................................................................................................................................... .12 2.1 Introduction ............................................................................................................................................................................................................................................................................................................................ .12 2.1.1 June 2012 - Belfast .......................................................................................................................................................................................................................................................12 2.1.2 January 2014 - NI Coastal Areas .........................................................................................................................................................................................12 2.1.3 January and February 2016 Lough Neagh & Lough Erne Flooding ...............................13 2.1.4 August 2017 - Foyle and Faughan River Catchments ...........................................................................................17 3 Available Datasets Relating to Flood Risk ........................................................................................................................................................................................... .19 3.1 Introduction ............................................................................................................................................................................................................................................................................................................................ .19 3.2 Base Data – Sources ................................................................................................................................................................................................................................................................................... .19 3.3 Base Data – Pathways .......................................................................................................................................................................................................................................................................... .19 3.4 Base Data – Receptors .......................................................................................................................................................................................................................................................................20 4 Methodology .................................................................................................................................................................................................................................................................................................................................................22 4.1 Introduction .............................................................................................................................................................................................................................................................................................................................22 4.2 Climate Change ......................................................................................................................................................................................................................................................................................................... .24 4.3 Source and Receptor Data Analysis .................................................................................................................................................................................................... .24 4.3.1 Source Data...............................................................................................................................................................................................................................................................................................24 4.3.2 Receptor Data ....................................................................................................................................................................................................................................................................................24 4.4 Risk Analysis........................................................................................................................................................................................................................................................................................................................ .26 4.4.1 Grid-Based Analysis .......................................................................................................................................................................................................................................................27 4.4.2 Defining Cells for Initial FRAs ............................................................................................................................................................................................................27 4.4.3 Extending Initial FRAs ..............................................................................................................................................................................................................................................28 4.4.4 Refining Initial FRAs .......................................................................................................................................................................................................................................................29 5 Analysis Results ............................................................................................................................................................................................................................................................................................................................... .31 5.1 Flood Risk Area Summaries ............................................................................................................................................................................................................................................. .31 5.2 Climate Change Analysis.......................................................................................................................................................................................................................................................... .35 5.3 Areas of Potential Significant Flood Risk APSFR( ) ............................................................................................................................. .37 6 Conclusions ......................................................................................................................................................................................................................................................................................................................................................40