APPENDIX 13.1 FLOOD RISK ASSESSMENT FLOOD RISK ASSESSMENT FOR A PROPOSED AVIATION FUEL PIPELINE FROM DUBLIN PORT TO DUBLIN AIRPORT STAGE 1 – FLOOD RISK IDENTIFICATION MARCH 2015 TABLE OF CONTENTS PAGE 1 INTRODUCTION ........................................................................................................ 1 1.1 BACKGROUND ....................................................................................................... 1 1.2 SCOPE ................................................................................................................ 1 1.3 METHODOLOGY ...................................................................................................... 2 1.3.1 Stage 1 - Flood Risk Identification ......................................................................... 2 2 DEVELOPMENT PLANS AND POLICIES ....................................................................... 3 2.1 NATIONAL, REGIONAL AND LOCAL SPATIAL PLANS ............................................................. 3 2.1.1 National Development Plan 2007–2013 .................................................................. 3 2.1.2 Dublin City Development Plan (DCDP) 2011 - 2017 ................................................. 3 2.1.3 Fingal County Development Plan (FDP) 2011–2017 ................................................. 5 2.1.4 Dublin Airport Local Area Plan 2006....................................................................... 6 2.2 CONSULTATIONS WITH STATUTORY BODIES ..................................................................... 6 3 EXISTING HYDROLOGICAL ENVIRONMENT ............................................................... 8 3.1 GENERAL DESCRIPTION OF THE CATCHMENTS CROSSED ....................................................... 8 3.2 EXISTING AND PROPOSED DRAINAGE AND WATER SUPPLY SYTEMS ......................................... 12 3.3 EXISTING SITE GEOLOGY AND HYDROGEOLOGY ................................................................ 12 3.4 EXISTING FLOOD RECORDS ....................................................................................... 12 3.5 EXISTING FLOOD STUDIES AND SURVEYS....................................................................... 17 4 FLOOD RISK IDENTIFICATION ............................................................................... 22 4.1 VULNERABILITY OF DEVELOPMENT ............................................................................... 22 4.1.1 Risk of flooding from Groundwater Sources ........................................................... 22 4.1.2 Pluvial Flood Risk ............................................................................................... 22 4.1.3 Fluvial Flood Risk ............................................................................................... 23 4.1.4 Tidal Flood Risk ................................................................................................. 25 4.2 OVERVIEW OF FLOOD RISK IDENTIFICATION ................................................................... 26 4.2.1 Risk of Flooding to the Development .................................................................... 27 4.2.2 Risk of Flooding from the Development ................................................................. 27 4.2.3 Risk of Flooding from Groundwater Sources ........................................................... 27 4.2.4 Pluvial Flood Risk ............................................................................................... 27 4.2.5 Fluvial Flood Risk ............................................................................................... 27 4.2.6 Tidal Flood Risk ................................................................................................. 28 4.3 JUSTIFICATION TEST .............................................................................................. 28 4.3.1 Residual Risks ................................................................................................... 28 5 CONCLUSIONS AND RECOMMENDATIONS ............................................................... 29 APPENDICES Appendix 1: Figure 1.2 (North Central) from the FloodReslienCity Project) Appendix 2: Flood Risk Identification Mapping Q:/2010/LE10/727/01/Reports/Rpt001-1.doc i/ii LIST OF TABLES PAGE Table 3.1: Pipeline Crossing Details at Streams and Rivers ............................................... 11 Table 3.2: Historical Flood Incidents .............................................................................. 12 LIST OF FIGURES Figure 3.1: Waterbody Catchment Map ........................................................................... 10 Figure 3.2: Flood Zones Overview Map ............................................................................ 16 Figure 3.3: DCFPP Project Map C1.4 ............................................................................... 18 Figure 3.4: DCFPP Project Map C1.5 ............................................................................... 18 Q:/2010/LE10/727/01/Reports/Rpt001-1.doc ii/ii Section 1 Fingleton White & Company Ltd. Flood Risk Assessment – Stage 1 1 INTRODUCTION 1.1 Background Fehily Timoney & Company was commissioned by Fingleton White (FW) to prepare a flood risk assessment for the proposed aviation fuel pipeline from Dublin Port to Dublin Airport in support of the Environmental Impact Statement (EIS) and planning application for this development. This report contains the first stage of the flood risk assessment, the flood risk identification. The flood risk identification Stage 1 report was prepared in accordance with the guidelines produced by the Department of the Environment, Heritage and Local Government (DoEHLG) - The Planning System and Flood Risk Management Guidelines for Planning Authorities, November 2009. 1.2 Scope The geographical scope of the flood risk assessment for the proposed development comprises any watercourse and floodplain that is intersected by the proposed scheme alignment and/or situated within a corridor of 25 m either side of the proposed pipeline corridor, which includes the public road, footway and verges within the boundary lines between public and private property. As the proposed pipeline is to be constructed generally in an urban setting and will be limited to within the proposed pipeline corridor, the receptors will be generally located within 10-25 m of the construction activities. The flood risk assessment also examined the wider catchment influences on these watercourses. The assessment took cognisance of any environmentally protected areas along these hydrological pathways. The proposed development comprises a 200 mm nominal bore (NB) pipeline to transport aviation fuel from a inlet station at Dublin Port to a reception station at Dublin Airport. The pipeline will be 14.4 km in length located predominantly within the road carriageway along the route. At the northern extent of the scheme, at Dublin Airport, the pipeline corridor will pass through the DAA Long Term Car Park (Red). A short section of the pipeline will traverse Athletic Union League (AUL) Sports Complex at Clonshaugh. The pipeline will also cross over the Dublin Port tunnel. It is proposed to cross seven river/stream crossings, five of which are culverted at the location of the crossing. Above Ground Stations will be required at both Dublin Port and Dublin Airport. These installations will be designed to pump and receive fuel and to control and monitor the quality and quantity of fuel being transported. The inlet station at Dublin Port and the reception station at Dublin Airport are existing facilities which will be modified to accommodate the proposed pipeline. Detailed strip mapping at a scale of 1:1000 was available for the entire pipeline corridor of 14.4 km. This strip mapping was examined along each section to determine the likely potential flood risk to and from the proposed development. The pipeline passes through two local authority functional areas namely, Dublin City Council (DCC) (from Dublin Port to Clonshaugh) and Fingal County Council (FCC) (from Clonshaugh to Dublin Airport). Figure 3.1 shows the proposed route of the pipeline. The catchments crossed by the proposed development are in Hydrometric Area HA09 passing through the Mayne and Santry River catchments and the coastal catchments of the Tolka and Mayne Rivers. There are seven watercourse crossings in all along the pipeline route. Five of these crossings are culverted at the location of the proposed crossing points. These rivers are under the responsibility of the Eastern River Basin District and Inland Fisheries Ireland. In the EIS, Chapter 13 Hydrology and Water Quality, the location of known existing foul, combined and stormwater collection systems and watermains was identified in Figure 13.5 and Figure 13.6. Cognisance was taken in this flood risk assessment of the potential flood risk where there are clashes with these networks in the jurisdictions of DCC and FCC. The layout of proposed sewerage schemes and watermain schemes was also examined. There is a network of stormwater gullies and manholes servicing the area where the pipeline corridor will pass through the DAA Long Term Car Park (Red). The developer will liaise with DAA to confirm the location of services in this area before construction commences. In addition, the location of services will be proofed using slit trenches and scanning equipment where necessary. Q:/2010/LE10/727/01/Reports/Rpt001-1.doc Page 1 of 29 Section 1 Fingleton White & Company Ltd. Flood Risk Assessment – Stage