Celtic Interconnector Project – Marine Consultancy and Engineering Services Land Report
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EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES LAND REPORT Report Reference: P1812_R3400_Rev2 Issued: 17 November 2014 Intertek Exchange House Liphook Hants GU30 7DW United Kingdom Tel: +44 (0) 1428 727800 Fax: +44 (0) 1428 727122 E-mail: [email protected] Web Site: www.intertek.com EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES SUMMARY Intertek has been commissioned, under its marine consultancy and engineering services contract, to provide a cable landing review for the proposed HVDC Celtic Interconnector cable for EirGrid and RTE. The objective of the study is to establish the least constrained landfall locations from a marine perspective, for further seabed survey. Intertek conducted Landfall site visits for both the Irish & French sites. In Ireland the ten proposed sites fell into two regions, five near Cork and five near Wexford/Waterford. In France, a total of six potential sites were considered, all in the Brittany region. The site visits were conducted during the period 4th – 7th November 2013 for the Irish landings and 20th – 22nd November 2013 for the French landings. The objective of the site visits was to assess each proposed site for its suitability as a cable landing site, factoring in all aspects involved in a cable installation. Each site was scored using a weighted system to accurately depict which sites were the most preferred and why. The results of the scoring exercise are presented in Section 5 – Landfall Rankings. There are a number of recommendations made within this document that should be considered in the final engineering solution for a successful installation. These are set out in Section 6 – Conclusions & Recommendations for Further Work. The recommendations from this Landfall report should be considered, along with the cable Route Investigation Report for the marine route, when scoping the marine survey solution. REPORT REFERENCE: P1812_R3400_REV2 18/11/2014 EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES CONTENTS 1 INTRODUCTION ................................................................................................. 1 1.1 BACKGROUND ....................................................................................................... 1 1.2 SCOPE OF WORK ................................................................................................... 3 1.3 SUPPLIED INFORMATION ......................................................................................... 3 1.4 BACKGROUND INFORMATION .................................................................................. 3 2 METHODOLOGY ................................................................................................ 4 3 STUDY AREA / SITE OVERVIEW ...................................................................... 6 3.1 IRELAND................................................................................................................ 6 3.2 FRANCE ................................................................................................................ 7 4 LANDING SITE DETAILS .................................................................................. 8 4.1 IRELAND LANDFALL OPTIONS .................................................................................. 8 4.2 FRANCE LANDFALL OPTIONS ................................................................................ 75 5 LANDFALL RANKINGS ................................................................................. 141 5.1 INTRODUCTION .................................................................................................. 141 5.2 RANKING METHODOLOGY ................................................................................... 141 5.3 IRISH MATRIX RANKINGS .................................................................................... 143 5.4 FRENCH MATRIX RANKINGS ................................................................................ 144 5.5 FINDINGS .......................................................................................................... 145 6 CONCLUSIONS & RECOMMENDATIONS FOR FURTHER WORK ............. 148 APPENDIX A CABLE LANDING INSTALLATION METHODS ............................ A-1 A.1 CUT TRENCH ..................................................................................................... A-1 A.2 HORIZONTAL DIRECTIONAL DRILLING................................................................... A-2 A.3 AUGER BORING ................................................................................................. A-4 A.4 CONSTRUCTION SITE FOOTPRINTS ...................................................................... A-6 APPENDIX B KEY ENVIRONMENTAL DESIGNATIONS WITHIN THE STUDY AREA…………… .................................................................................................... B-1 REPORT REFERENCE: P1812_R3400_REV2 18/11/2014 EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES TABLES TABLE 2-1 CABLE LANDING CRITERIA ....................................................................................... 5 TABLE 3-1 IRISH LANDFALL SITES ............................................................................................. 6 TABLE 3-2 FRENCH LANDFALL SITES ........................................................................................ 7 TABLE 5-1 IRISH MATRIX RANKINGS .................................................................................... 143 TABLE 5-2 FRENCH MATRIX RANKINGS ............................................................................... 144 REPORT REFERENCE: P1812_R3400_REV2 18/11/2014 EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES FIGURES FIGURE 1-1 STUDY AREA FOR THE LANDFALL SITES .................................................................. 2 FIGURE 3-1 OVERVIEW OF IRISH LANDFALL SITES ..................................................................... 6 FIGURE 3-2 OVERVIEW OF THE FRENCH LANDFALL SITES ......................................................... 7 FIGURE 4-1 INCH BEACH APPROACH ....................................................................................... 8 FIGURE 4-2 INCH BEACH BEDROCK GEOLOGY .......................................................................... 9 FIGURE 4-3 BURIED PIPELINE ................................................................................................ 10 FIGURE 4-4 INCH BEACH LOOKING SOUTH WEST .................................................................... 12 FIGURE 4-5 FORESHORE AND BACKSHORE BERM LOOKING NORTH WEST TO W. STREAM OUTFALL ........................................................................................................................ 12 FIGURE 4-6 BACKSHORE BERM LOOKING NORTH EAST TO EASTERN STREAM OUTFALL ............ 12 FIGURE 4-7 FORESHORE AND BACKSHORE BERM LOOKING NORTH EAST ................................. 12 FIGURE 4-8 ROCK OUTCROP LOOKING WEST TOWARDS COBH HARBOUR ENTRANCE ............... 13 FIGURE 4-9 HWM LOOKING WEST TO COASTGUARD’S LOOKOUT ............................................ 13 FIGURE 4-10 HWM LOOKING SOUTH EAST............................................................................. 13 FIGURE 4-11 EASTERN FORESHORE ...................................................................................... 13 FIGURE 4-12 BALLYCRONEEN BEACH .................................................................................... 15 FIGURE 4-13 LOCATION OF BALLYCRONEEN BEACH ............................................................... 15 FIGURE 4-14 RIVER DISCHARGING ONTO BALLYCRONEEN BEACH ........................................... 16 FIGURE 4-15 STORM BERM WITH SEA DEFENCE BOULDERS LOOKING EAST .............................. 17 FIGURE 4-16 STORM BERM LOOKING NORTH .......................................................................... 17 FIGURE 4-17 BALLYCRONEEN BEDROCK GEOLOGY ................................................................ 17 FIGURE 4-18 WEST SIDE OF BEACH ROCK OUTCROP LOOKING EAST ........................................ 18 FIGURE 4-19 EAST SIDE OF BEACH ROCK OUTCROP LOOKING EAST ......................................... 18 FIGURE 4-20 BALLYCRONEEN BEACH LOOKING NORTH WEST ................................................. 20 FIGURE 4-21 WEST SIDE OF BEACH ROCK OUTCROP LOOKING WEST ....................................... 20 FIGURE 4-22 BALLYCRONEEN BEACH LOOKING NORTH .......................................................... 20 FIGURE 4-23 STORM BERM LOOKING NORTH .......................................................................... 20 FIGURE 4-24 BALLINWILLING STRAND.................................................................................... 22 FIGURE 4-25 LOCATION OF BALLINWILLING STRAND ............................................................... 22 FIGURE 4-26 PRIMARY BEACH ACCESS VIA CONCRETE SLIPWAY THROUGH SEA DEFENCES ....... 23 FIGURE 4-27 ALTERNATIVE BEACH ACCESS POINT .................................................................. 23 FIGURE 4-28 BALLINWILLING GEOLOGY. NOTE ROCK OUTCROP .............................................. 24 FIGURE 4-29 BALLINWILLING STRAND.................................................................................... 24 REPORT REFERENCE: P1812_R3400_REV2 18/11/2014 EIRGRID & RTE CELTIC INTERCONNECTOR PROJECT – MARINE CONSULTANCY AND ENGINEERING SERVICES FIGURE 4-30 EXPOSED DOLOMITIC LIMESTONE OUTCROP