Plans to divert the A303 into a tunnel close to Stonehenge has been supported by a new report from global heritage organisations but caution has been urged over the design of the portals.
The report from Unesco, the World Heritage Convention and the International Council on Monuments and Sites welcome the plan to build the 2.9km tunnel and calls it a “best practice case”.
Although the report believes the tunnel is the best solution, it has said that the “siting and design of the tunnel portals, approach cuttings/embankments, entry/exit ramps, mitigation measures and the temporary construction works have the potential to adversely impact on the outstanding universal value of the work”. The organisations have called for “rigorous investigation, evaluation, iterative design and assessment” of these aspects of the plans.
The report suggests that a heritage-centred steering group should be established to “ensure proper quality control at all stages of decision making, project design and implementation”. Another recommendation proposes that BIM and 3D visualisation should be used to inform the iterative option identification and selection process to minimise the impact of the work on the surrounding area.
A joint venture of Atkins and Arup was awarded the design contract for the Stonehenge tunnel by Highways England in January as part of the £15bn five-year Road Investment Strategy, the A303 between Amesbury and Berwick Down in Wiltshire. GE has contacted both consultants and Highways England for comment on the findings of this heritage report but no response has been received yet.