Cork Line Level Crossings Appendix 9A Flood Risk Assessment Iarnród Éireann
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Cork Line Level Crossings Appendix 9A Flood Risk Assessment Iarnród Éireann March 2021 Appendix 9A Flood Risk Assessment Client Name Appendix 9A Flood Risk Assessment Cork Line Level Crossings Project No: 32111000 Document Title: Appendix 9A Flood Risk Assessment Revision: P02 Date: March 2021 Client Name: Iarnród Éireann Project Manager: Alex Bradley Author: Ana Silva Jacobs U.K. Limited Artola House 3rd & 4th Floors 91 Victoria Street Belfast BT1 4PN T +44 (0)28 9032 4452 F +44 (0)28 9033 0713 www.jacobs.com © Copyright 2020 Please select a legal entity from the Change Document Details option on the Jacobs ribbon. The concepts and information contained in this document are the property of Jacobs. Use or copying of this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright. Limitation: This document has been prepared on behalf of, and for the exclusive use of Jacobs’ client, and is subject to, and issued in accordance with, the provisions of the contract between Jacobs and the client. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or reliance upon, this document by any third party. Document history and status Revision Date Description Author Checked Reviewed Approved P01 September Draft Stage 1 and 2 FRA AS PH PH NS 2019 P02 October Updated to include Stage 3 FRA AS PH PH NS 2020 P03 March For Issue to An Bord Pleanála HC NS NS AB 2021 Appendix 9A Flood Risk Assessment Contents 1. Introduction .............................................................................................................................................................................. 1 1.1 Introduction and Background ............................................................................................................................................ 1 1.2 Proposed Project Description ............................................................................................................................................ 3 1.3 Report Structure ...................................................................................................................................................................... 5 2. Flood Risk Assessment Methodology ............................................................................................................................. 6 3. Stage 1: Flood Risk Identification ..................................................................................................................................... 6 3.1 General ........................................................................................................................................................................................ 6 3.2 Flood Information Sources .................................................................................................................................................. 6 4. Stage 2: Initial Flood Risk Assessment – Potential Impacts to the proposed Project ............................... 11 4.1 Potential Sources of Flooding ......................................................................................................................................... 11 4.2 Coastal Flood Risk ............................................................................................................................................................... 11 4.3 Fluvial Flood Risk ................................................................................................................................................................. 11 4.4 Estuarine Flood Risk............................................................................................................................................................ 14 4.5 Pluvial Flood Risk ................................................................................................................................................................. 14 4.6 Artificial Drainage Systems .............................................................................................................................................. 14 4.7 Reservoirs and Other Artificial Sources ....................................................................................................................... 15 4.8 Groundwater Flood Risk .................................................................................................................................................... 15 4.9 Summary of Flood Risk ...................................................................................................................................................... 15 4.10 Flood Risk due to Climate Change ................................................................................................................................ 16 5. Stage 2: Initial Flood Risk Assessment – Potential Impacts from the proposed Project ......................... 17 5.1 Impacts on Coastal and Estuarine Flooding .............................................................................................................. 17 5.2 Impacts on Fluvial Flooding ............................................................................................................................................ 17 5.3 Impacts on Pluvial Flooding ............................................................................................................................................ 20 5.4 Impacts on Flooding from Artificial Drainage Systems ........................................................................................ 20 5.5 Impacts on Groundwater Flooding ............................................................................................................................... 21 6. Stage 3: Detailed Flood Risk Assessment .................................................................................................................. 23 6.1 General ..................................................................................................................................................................................... 23 6.2 Hydrological Analysis ......................................................................................................................................................... 23 6.3 Hydraulic Model ................................................................................................................................................................... 24 6.4 Summary of impacts on Fluvial Flooding at XC219 Buttevant ......................................................................... 27 6.5 Conclusion .............................................................................................................................................................................. 29 7. Sequential Approach to Development Planning ..................................................................................................... 29 7.1 XC187 - Fantstown ............................................................................................................................................................. 30 7.2 XC201 - Thomastown ........................................................................................................................................................ 30 7.3 XC209 – Ballyhay ................................................................................................................................................................. 31 7.4 XC211 / 212 – Newtown / Ballycoskery ..................................................................................................................... 31 7.5 XC215 Shinanagh ................................................................................................................................................................ 32 7.6 XC219 Buttevant .................................................................................................................................................................. 32 Appendix 9A Flood Risk Assessment 8. Conclusion .............................................................................................................................................................................. 33 Table 1.1 Proposed Project at each Level Crossing .................................................................................................................. 4 Table 4.1 River Awbeg Flood Level Estimation for site XC19 Buttevant ....................................................................... 13 Table 4.2 Summary of Flood Risk to Proposed Project on all sites ................................................................................. 15 Table 4.3 Climate Change Forecasts ........................................................................................................................................... 16 Table 4.4 Climate Change Impacts ............................................................................................................................................... 16 Table 5.1: Pepperhill Stream Flood Level Estimation for site XC219 Buttevant ....................................................... 19 Table 6.1 : Peak Design Flows for Pepperhill Stream and River Awbeg ........................................................................ 24 Table 6.2 Hydraulic Model Boundary Conditions ................................................................................................................... 25 Table