Connie Kelleher

The work of the Underwater Archaeological Unit and mitigation measures for dredgings and archaeology

The Underwater Archaeological Unit is an intrinsic part of Dúchas the Heritage Service within the National Monuments and Architectural Protection Division of the Dept. of Arts, Heritage, Gaeltacht and the Islands. Established in August 2000, the Unit is co-directed by Karl Brady and Connie Kelleher and has three other members - Fionnbarr Moore, Caroline Rock and Auriel Robinson, four of who are commercially trained divers qualified to HSE Part 1 (offshore). The Unit was set up to undertake the management and protection of our underwater cultural resource and within this it has several key functions. These include survey, planning, inspection, monitoring, licensing, publication and liaison with the sports diving community and the public at large.

It would be in the areas of survey and planning that the Unit would focus most of its time. With one brief feeding into the other in a symbiotic manner, the Unit endeavours through survey to undertake rapid reconnaissance and assessments of areas that are to be impacted by development. In turn, when undertaking inspection for planning applications or on-going archaeological work, the Unit takes the opportunity to carry out a general survey of that area.

The Unit undertakes specific archaeological survey projects, with the main project for 2001 being a joint one of the medieval harbour of Castlehaven, Co. Cork and the site of the 1697 man of war wreck the HMS Looe in Baltimore, Co. Cork. Both areas produced exciting results and diving survey work on the HMS Looe is still ongoing. This summer the Underwater Unit will be undertaking a detailed interdisciplinary survey of Lough Swilly in Co. Donegal, comprising intertidal, aerial, geophysical and diver survey. The Unit will also be undertaking diver survey of a number of crannog sites in Lough Derravaragh in Co. Westmeath for Aidan O' Sullivan of the Archaeology Department of University College Dublin, who is directing the survey work there.

The Unit is compiling a National Shipwreck Inventory for the Republic and Volume 1 of the Shipwrecks of Counties Louth, Meath, Dublin and Wicklow is due to be published in early 2003. A booklet and associated leaflets on the role of the Underwater Unit are also due for publication shortly.

The Unit assesses approximately 700 applications per year of proposed developments in the marine, riverine and lacustrine environments. In areas of archaeological potential, the Unit will recommend archaeological mitigation and will liase with the archaeological consultant who undertakes this work.

The Unit also has a specific monitoring brief for diving expeditions that focuses primarily on two sites every year - that of the RMS Lusitania off Cork and the site of the three Spanish Armada shipwrecks of 1588 at Streedagh Strand in Co. Sligo.

As part of either commercial archaeological work or sports diving on protected sites the Underwater Unit oversees the issuing of dive licences which are processed by the Licensing Section of Dúchas. The National Museum of Ireland also has a consultory role in the issuing of such licences. All wrecks over 100 years old are automatically protected under the National Monuments Acts 1930-1994 and a licence is required to dive on such sites. Certain other sites such as the RMS Lusitania, due to their intrinsic historical value, are also protected by an Underwater Heritage Order and a licence is also required for diving on this site.

Dredgings of ports and harbours is ongoing in the Republic and the Underwater Unit mitigates for potential impacts associated with such schemes. There are various pieces of legislation which can be drawn upon in order to address and protect the underwater cultural heritage. These include our own National Monuments Acts 1930-1994, Dumping at Sea Act 1996 and the Foreshore Acts of 1933 and 1992. Under these Acts all applications for foreshore licences or dumping at sea licences are referred to the Underwater Unit by the Dept. of Marine and Natural Resources for consideration. The Unit assesses each one and forwards any archaeological requirements to the Dept. of Marine, which is then appended to the conditions attached to the licence.

As part of the required archaeological mitigation for such dredgings works, the Unit requests that a full archaeological assessment to be carried out in advance of dredgings. This will include a detailed desktop historical review and either geophysical survey, intertidal survey and diver survey (or all three in the case of large dredging programmes) would be key components of each assessment. Each dredging programme is individually assessed and requirements made according to the potential of the area, particularly in regard to our record of shipwrecks. Private-sector archaeologists are contracted by the developers to undertaken the archaeological requirements. A full geophysical survey is usually carried out of the area to be dredged and any identified anomalies are then archaeologically diver-truthed. Offshore dumpsites are equally assessed through geophysics and diver survey. The contracted archaeologist forwards the archaeological assessment report to the Underwater Archaeological Unit for review prior to any dredgings beginning and, based on the results of the assessment, further archaeological mitigation may be required. Should archaeology be identified, at this stage, preservation in situ is the preferred option through avoidance. However, if avoidance is not possible, full archaeological excavation would be carried out.

Archaeological monitors are also required to be present on board the dredger during the works. This is the case for all capital dredging works but also for maintenance dredging in some cases where the area being dredged is one of high archaeological potential and/or produced significant archaeology during the capital dredging works. Archaeological monitoring has proven extremely effective in the recovery and protection of archaeology, with numerous shipwrecks, fishtraps and thousands of artefacts being located during the course of various dredgings programmes such as that at New Ross in Co. Wexford, Waterford Port and Drogheda Port in Co. Louth. Recent discoveries include three shipwrecks located during dredgings for the Dublin Bay Pipeline, one with a potential 17th century date. Another substantial shipwreck has been located in Waterford Estuary that also appears to be of 17th century date and may be the HMS Hastings that was wrecked there in 1697. Over 6,000 artefacts dating from all periods from prehistory to post-medieval times were recovered during the monitoring of the dumping of dredged spoil at Drogheda Estuary. All dumped material was screened and an artefact retrieval strategy put in place. Examples of artefacts included a socketed Late Bronze Age spearhead, some 3,000 flint artefacts, medieval human remains and Roman pottery dating to the 3rd century AD.

The Unit is presently involved in the formulation of Guidelines and Codes of Practice with the Port Authorities for port and harbour works. Guidelines are also being considered for Oil and Gas Exploration. Discussions are also pending with the Irish Underwater Council to formulate protocols for leisure users and archaeology.