The Stonehenge Bypass Tunnel project in the UK continues to be a source of controversy. The latest development comes in the shape of a warning from Unesco, which has told the UK government that the famous Stonehenge monument may lose its status as a world heritage site unless the proposed tunnel route is changed.
Unesco is calling for the design of the £1.7 billion tunnel, currently planned to be 3.2km long, to be lengthened. This would ensure that the portals do not cause damage to archeological sites of importance in the area. As a result, Unesco has asked the UK Government to provide updated plans by February 2022. The project has been an important one for Highways England and is needed to improve transport in the area. Whether the UK Government will be able to tolerate yet another cost increase remains to be seen.
The UK Government has approved the project but following another legal challenge, the approval process has been questioned and faces further battles in court. It now seems likely that the project will be stalled until a resolution can be found.
There have been plans to build a bypass tunnel previously but these were cancelled on ground of cost. The A303 is a dual carriageway for much of its length but features a single lane in either direction where it passes the famous Stonehenge monument. The A303 is busy and carries particularly heavy traffic during vacation periods when it becomes a popular tourist route, while the road also carries a high percentage of heavy truck traffic. The stretch with a single lane in either direction is subject to heavy congestion and delays, while there are also safety concerns and the upgrades have been long awaited.
Driving the bore, fitting the necessary electrical and mechanical systems, as well as the drainage mitigation systems will be costly as the ground conditions are poor and the water table is high. The tunnel construction will require extensive support, with comprehensive waterproofing and systems to ensure the water table is unaffected and also that there is no risk of contamination from water run-off.
The proposals to construct the tunnel have met with resistance on environmental and archaeological grounds. Stonehenge dates back around 4,000 years and is considered one of the most historically important monuments in Europe. The area surrounding the monument has been a centre for human activity for several thousand years and is also noted for its many archaeological sites of interest. The project’s critics say that building the tunnel threatens other potential archaeological finds, as well as posing a threat to the local environment.