An international expert has warned that the status of Bru na Boinne as a world heritage site could be under threat from the proposed Slane Bypass.
Dr Douglas Comer, who is a leading expert on such sites, has prepared an heritage impact assessment on Bru na Boinne for Meath Council Council following a recommendation by An Bord Pleanala that such a study be conducted as part of its request for further information on the project.
Some further study should be done to determine the likely impact of the project on the site and to examine in greater detail possible alternatives to solving the traffic problems of Slane, according to the professor.
The report noted that the key issue is how the introduction of modern infrastructure such as the new bypass and bridge would affect the experience of being in and passing through the landscape of the World Heritage Site.
Dr Comer has said that failure to maintain the outstanding universal value of the site which includes Knowth, Dowth and Newgrange could threaten its status.
"The question is how much of the bypass and the bridge would be visible from within the site," he said.
The site has already been affected by the M1 motorway and bridge, the cement factory chimneys at Platin, the stack of the Carranstown incinerator and a number of housing developments as they can be seen from parts of both Knowth and Dowth, according to the report.
"So as time goes on and you add all of these factors, at a certain point in time you come to a place where you've really compromised the environment that makes Brú na Bóinne so special," he said.
Dr Comer said the building of the new bypass could pave the way for further development 'that would actually constitute a bigger threat to the outstanding universal value of Brú na Bóinne because these developments would almost surely be visible within the site.'
The report had identified some gaps in the council's information on the visibility of the proposed new bridge over the Boyne, according to Dr Comer.
What we're suggesting is that a balloon test be conducted - with an inflatable balloon put in position where the bridge would be located. That's a very transparent way to determine just what could be seen from different parts of the World Heritage Site,' he said.
Dr Comer said he recognised the fears of Slane residents and has recommended that detailed studies should be carried out on the all aspects of imposing and implementing a ban on heavy goods vehicles travelling through the village and directing traffic away from the N2 in the Slane area as a means of dealing with the problem.
Professor George Eogan, who has been involved with the excavations at Brú na Bóinne for more than 50 years, criticised the project and said the site was a microcosm of the archaeology of Ireland - its architectural and engineering marvels were the embodiment of genius and its preservation was essential.
The Newgrange visitors centre had been built on the south side off the river to prevent traffic coming through Brú na Bóinne which had been a site of importance down the ages. He said the area was now saturated by roads and already impinged on by the M1 motorway.
Prof Eogan said he now believed the buffer zone set up around the site was too restrictive adding that he felt certain areas to the east and west could be extended slightly.
He said the recent discovery of a souterrain on Mr Rogers' land gave ' a strong indication that sites will turn up so the buffer zone can now be considered as not sufficiently large enough."
Dr Mark Clinton of An Taisce's Monuments and Antiquities Committee said he believed the bypass would create as many problems as it would resolve and was a Roads Authority Trojan Horse - a quasi motorway extending from Ashbourne to Ardee. Referring to the experience of finds made at Lismullin during the work on the N3, he said it was unacceptable that such finds and finds that might be made during work on the Slane Bypass would be only preserved by record.
Engineer James Leahy, a member of An Taisce involved in restoring the Boyne Canal between Drogheda and Navan, said their were deficiencies in the Environmental Impact Statement prepared by the council as it did not adequately address mitigation measures to deal with the impact on the Boyne navigation or how a planned cycleway on the west side of the new bridge would link into the walkway along the canal towpath.
Meanwhile, heritage office with An Taisce, Ian Lumley said the application for the bypass would be viewed as a legacy of a decade and a half of strategic planning failure by the NRA and Meath County Council. He claimed the proximity of Slane to the M1 and Navan meant there was no justification for maintaining three national roads so close together.
Environmentalist Peter Sweetman argued that the information given by Meath County Council was not adequate enough for Bord Pleanála to make the right decision and the holding of the hearing had been premature.