Fibre-Optic Cable Landfall Ballycotton Bay Archaeological Desktop Review
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FIBRE-OPTIC CABLE LANDFALL BALLYCOTTON BAY ARCHAEOLOGICAL DESKTOP REVIEW THE ARCHAEOLOGICAL DIVING COMPANY LTD. FIBRE-OPTIC CABLE LANDFALL BALLYCOTTON BAY ARCHAEOLOGICAL DESKTOP REVIEW 11 August 2014 Project Director Dr. Niall Brady Brehon House, Kilkenny Road, Castlecomer, Co. Kilkenny [email protected] THE ARCHAEOLOGICAL DIVING COMPANY LTD. TABLE OF CONTENTS LIST OF ABBREVIATIONS 1 EXECUTIVE SUMMARY 2 LIST OF FIGURES 4 1.0 INTRODUCTION 5 2.0 THE PROPOSED DEVELOPMENT 6 3.0 ASSESSMENT METHODOLOGY 7 4.0 THE RECEIVING ENVIRONMENT 11 5.0 MITIGATION PROPOSALS 18 6.0 APPENDIX 1: RECORDED SHIPWRECKING EVENTS, BALLYCOTTON BAY 23 7.0 APPENDIX 2: KNOWN SHIPWRECKING EVENTS, BALLYCOTTON BAY 32 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork LIST OF ABBREVIATIONS ADCO The Archaeological Diving Company Ltd BMH Beach Manhole DAHG Department of Arts, Heritage and the Gaeltacht E Easting GSI Geological Survey of Ireland INFOMAR Integrated mapping for the sustainable development of Ireland’s marine resource INSS Irish National Seabed Survey N Northing NGR National Grid Reference NIAH National Inventory of Architectural Heritage NMI National Museum of Ireland OPW Office of Public Works RMP Record of Monuments and Places RPS Record of Protected Structures UKHO United Kingdom Hydrographic Office UTM Universal Transverse Mercator < Less than > More than ADCO 1 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork EXECUTIVE SUMMARY The Archaeological Diving Company Ltd (ADCO) was commissioned by PiPiper Ltd to undertake an archaeological desktop review of the sea area within Ireland’s 12 nautical mile limit for a fibre-optic cable network, as it makes landfall in Ballycotton Bay, Co. Cork. Desktop assessment is a preliminary stage in archaeological mitigation for any given project. It identifies and charts the known archaeological information within the context of the particular project, and makes appropriate recommendations for further work. The Beach Manhole (BMH) location is within 40m of an archaeological site, CO 89-78, which has been developed into a residential complex. Investigations in 2006-7 did not reveal material of archaeological significance in this location. The cable route offshore to 12 nautical miles includes numbers of recorded shipwrecking events and 17 known shipwreck locations. There are five known shipwreck locations that lie within 1500m of the proposed cable centerline, and one shipwreck that lies c. 500m from the centreline. The cable centerline does not directly impact on any known shipwreck site. There is no archaeological reason why the development proposal should not proceed. The recommendations of this report include: ñ An archaeological consultant specializing and experienced in maritime and underwater archaeology should be appointed to undertake and/or oversee the archaeological mitigations. ñ Intertidal survey will be necessary at the landfall location. ñ The location of the BMH within 40m of the archaeological site C O 89-78 may anticipate a requirement to investigate areas of impact that are considered to lie close to C O 89-78. ñ The project-specific marine geophysical survey to be carrie d out along the cable route should qualify the presence or the absence of recorded and known wrecksites along the route. The work should also understand the nature of the seabed deposits, to permit informed statements concerning the character of the seabed surface and substrate, and its ability to expose and conceal cultural materials, including shipwrecks and (for the nearshore area) submerged landscapes. ñ Archaeological dive survey may be necessary to cover any data -gaps in the marine geophysical survey, especially between the nearshore and the Low Water Mark. Archaeological dive survey can also be anticipated to inspect anomalies identified in the marine geophysical survey. Inspections in deep water will require ROV/other non-diver means. ADCO 2 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork ñ Archaeological monitoring is recommended during the cable-lay operation, including the pre-grapnel survey, to resolve any archaeological material that may become exposed at that point. ñ Archaeological site work requires archaeological licenses, granted by the DAHG, and sufficient lead-time is required to ensure the licenses are in place before archaeologically-related site works take place. Recommendations are subject to the approval of the National Monuments Section at the DAHG. ADCO 3 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork LIST OF FIGURES Figure 1: Detail from Admiralty Chart showing proposed cable route between Ballycotton Bay and the 12nm limit. Figure 2: Known archaeological sites at the landfall location. Figure 3: Known shipwreck locations within the 12nm limit close to the cable route. ADCO 4 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork 1.0 INTRODUCTION 1.1 General The Archaeological Diving Company Ltd (ADCO) was commissioned by PiPiper Ltd to undertake an archaeological desktop review of the sea area for a fibre-optic cable network, as it makes landfall in Ballycotton Bay, Co. Cork. The study is informed by a requirement identified by the Department of Arts, Heritage and the Gaeltacht (DAHG) in relation to the overall project, which will ultimately extend to include site surveys and intertidal inspections.1 The current report presents the archaeological observations for the landfall location and the sea area within the 12 nautical mile territorial limit, and includes details relating to the procurement of archaeological mitigation requirements for future site- related work associated with the project. 1.2 Location A route option for the subsea fibre-optic cable project has been prepared that seeks to provide a safe and economic route for the lifetime of the cable.2 The project will extend the network to Ireland, making landfall at Ballycotton Bay (Figure 1). Two route options are being considered, lying up to 500m apart at sea within the 12-mile limit and sharing the same landfall. Ballycotton Bay lies between Cork Harbour on its west side, and Youghal Bay on its east side, with the Celtic Sea to its south. Ballycotton village lies at the tip of a low headland, which extends south to create a sheltered haven at the head of Ballycotton Bay on its west side. The cable is to approach from the southeast and will make landfall at the head of the bay north of the village, in Garryvoe Lower townland, at UTM 29N 569378E 5746096N. 1 Correspondence G Pre00119-2014. 2 Detail relating to the landfall is laying method is provided in No Name, Joshua. Submarine for Alcatel-Lucent Submarine Networks, 04/06/2014. ADCO 5 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork 2.0 THE PROPOSED DEVELOPMENT The precise cable route will be subject to the results of detailed survey, which will be carried out near- and inshore within a c. 200m-wide corridor. In water depths greater than 1,000m the cable is considered to be secure enough to lie on the seabed floor. In water depths of 1,000m and less, it is proposed to bury the cable to 1m depth where seabed sediment permits. In shallower water, where rock exposure is encountered, the cable may be run over the rock, and provided protection by lying inside an articulated pipe. A pre-lay grapnel run will be carried out immediately prior to the cable-lay operation, to assist with the removal of obstacles. At sea, where sediment permits, the cable will be buried using a marine plough system, which cuts into soft sediment, lays and buries the cable in the one motion. The cable will be pulled ashore and buried up to 2m deep across the beach, which will be excavated by open-cut trenching. The cable will cross the foreshore, and terminate inland at a Beach Manhole (BMH), which is to be located above the High Water Springs in Garryvoe Lower townland. ADCO 6 Archaeological Desktop Review Fibre-optic cable landfall Ballycotton Bay, Co. Cork 3.0 ASSESSMENT METHODOLOGY A sequence of work has been completed to ensure that the archaeological desktop review has been comprehensive and robust. The work has included a study of known archaeological and architectural sources, and a review of licensed archaeological work conducted on the terrestrial site area. 3.1 Consultations The following sources of information have been consulted: ° The Irish Antiquities Division of the National Museum of Ireland (NMI) retains an extensive archive of small finds and objects discovered across Ireland and reported to the Museum and its predecessors since the nineteenth century. It represents a critical resource for archaeological research, where registered objects are recorded by townland in the Topographical Files. For the present project, the following townlands were assessed: Ardnaninch; Ballycrenane; Ballylongane; Ballynamona; Ballynangna; Ballybramer; Garryvoe Lower. ° Department of Arts, Heritage and the Gaeltacht (DAHG) Sites and Monuments Record files. The information, which is also filed according to townland, provides details relating to specific monuments and sites of archaeological importance that survive or whose site area is recorded. The record generally includes only sites that pre-date c. 1750 AD. ° Historic Shipwreck Inventory files and Places and Ports archive. This information relates to the archives maintained by the National maritime sites of archaeological interest. The information is located with reference