ng solution should
be included in a current, long-term plan (Davidson interview 15/3/99).
A case could be made for several small car parks placed around the edge
of the World Heritage site, to give walkers more ready access and to disperse
traffic. These could be concealed by trees and given an unobtrusive green
surface (Fowler interview 15/3/99).
The deep bore tunnel
Tunnel Vision identified two possible routes for a deep bore tunnel; a
long ('green route') tunnel, passing under the Avenue and Cursus and a
short ('purple route') tunnel passing under the Cursus. The short tunnel
proposal was quickly abandoned when it encountered universal opposition
from the local community (Tunnel Vision, annexe A, table A1). The longer
('green') tunnel would be approximately three and three-quarter kilometres
long (see figure 1). Until publication of the Master Plan, a deep bore
tunnel was the option favoured by both the National Trust and English
Heritage. Its direction was predicated on the need to minimise the slope
of the approach from the east, if the tunnel entrance were to be immediately
below King Barrows Ridge. In 1994, the Director General of the National
Trust, who own land on which cut-and-cover tunnel would be dug, said the
long-bore tunnel was the only feasible alternative which met World Heritage
site requirements (quoted in Fielden 1998: 735). This view was endorsed
by the Highways Agency Planning conference held in November 1995 and described
in Wainwright 1996. Wainwright changed his opinion because he was satisfied
the cut-and-cover tunnel was the only affordable option, and that it achieved
the main objective of enabling visitors to roam across the landscape around
Stonehenge (Wainwright, interview 24/2/99).
Cost of a deep bore tunnel. The cost of the longer deep
bore tunnel has been variously estimated at between £200 million
and £300 million (Tunnel Vision annexe A, Stone n.d.: 5, Wainwright
1996: 11). The method for arriving at these estimates has not been published
although Wainwright reports that foreign firms were consulted by the Department
of Transport (Wainwright, interview 24/2/99). In the words of the recent
editorial in Antiquity, the cost of the cut-and-cover tunnel has been
'plucked for discussion' (Anon 1998: 733). Lord Kennet's claim that a
3.2 km. single bore, two-track rail tunnel is being driven through North
Downs for £80 million (Kennet 1998: 736) appears however to disregard
infrastructural costs (Wainwright, interview 24/2/99). Neither the technical
specifications of the proposed deep bore tunnel, nor the geotechnical
survey on which the costing of a deep bore tunnel was based have been
published, but they would have to be made available at a public enquiry.
It has been suggested that additional funding could be sought from European
or international sources (Fielden 1998: 736). The suggestion that 'heritage
sources' should bear part of the cost contradicts, however, the 'polluter
pays' principle (Stone n.d.: 4). Indeed, enquiries made by the Wiltshire
Archaeological Society have ascertained that even if alternative sources
of funding were available, the cut-and-cover tunnel would still be the
preferred option of English Heritage (Fielden, interview 13/4/99).
One of us (RL) spoke to a qualified, professional civil
engineer who stated that the principal cost of a deep bore tunnel is setting
up the equipment, while the cost of a cut and cover tunnel is directly
related to its length. In general terms, a short (half-kilometre) deep
bore tunnel would be six times more expensive, a 2.5 kilometre deep bore
tunnel 35% more expensive than a cut and cover, but a four kilometre tunnel
only 10% more expensive. If the two kilometre cut and cover tunnel costs
£125 million, a four kilometre deep bore tunnel would cost £275
million. The new technique of spraying concrete onto the walls of the
bore is still viable. The recent collapse of the tunnel under construction
at Heathrow Airport was caused by the thinness of the sprayed concrete,
not an inherent defect in the method.
Wainwright reports that the 'green'