With the first phase of High speed Railway 2 (Birmingham-London) being firmly voted through the House of Commons last month, the National Trust has handed in a petition (along with many others) expressing our concerns about the scheme and suggestions as to how it could be improved.
The most frequent request from petitioners is that HS2 ltd needs to build a “fully bored tunnel” for the railway throughout the whole of the Chilterns Area of Outstanding Natural Beauty (AONB). This idea is supported by many inhabitants in the Chilterns, conservation groups, MPs and local authorities.
It begs the question, what is an AONB and why does it deserve to be protected to this degree against the HS2?
What is an AONB?
Many of us would know our nation’s National Parks, which include Dartmoor and the peak District. These receive special protection from insensitive development and often have their authorities to protect them.
AONB’s were made equal status with National Parks in 2000. They are considered to be areas that need protection to preserve their beauty and ecology, although they often don’t have the same judicial weight as National Parks and don’t have their own authorities. This might explain why HS2 have not accepted demands for a fully bored tunnel as of yet.
What makes the Chilterns special?
This area was designated an AONB due to:
- Landscape- HS2 would no doubt impede on the overall ‘natural beauty’ of this area which has not changed since medieval times
- Ecology- many conservation groups have pushed for the protection of ancient woodland (see previous post) and many habitats that will be disrupted by HS2. Not to mention the ecological barrier the track would create where no wildlife could pass.
- Noise- without proper mitigation tranquillity, in the Chiltern’s would be disturbed.
- Cultural heritage- Some people have expressed concern over the railway’s impact upon archaeology and damage to previously undisturbed Iron Age earth structures (not to mention all the grade II listed farm houses that will have to be demolished)
How should we protect the Chilterns?
So it is clear the Chilterns has irreplaceable aspects that need we need to conserve, so what are our choices?
This option is the least disruptive way to build HS2 through the Chilterns AONB.
Of course tunnelling is the most costly scheme, but seeing as HS2 already plans to tunnel halfway through the Chilterns many argue that it should be extended to span the full AONB.
Click here for the useful HS2 route map from Chilterns Conservation Board.
“Green Tunnel or Land Bridge”
The step down from a tunnel is the ‘green tunnel’ or ‘land-bridge’. This involves building embankments either side of the track, putting a lid on top, and placing earth and vegetation on top of that lid. (see last week’s post)
This reduces the impacts on ‘natural beauty’, noise and wildlife, and it is of course cheaper than boring straight into the ground.
However, as this landscaping scheme would be above ground it would still significantly disturb the landscape, ancient woodland and cultural heritage.
Click here for a clear illustrated guide to tunnels from the Woodland’s trust.
Cuttings, embankments and protective barriers
Failing all this, we then have other schemes to reduce the impact of the railway. Embankments and cuttings can partially protect the AONB from noise and visual impacts.
Noise barriers also will stop most of the noise from the railway but will need to be screened by trees to protect the landscape.
Of course, this sort of scheme will have the most negative impact on wildlife, ancient woodland and cultural heritage.
At the moment HS2 are using a combination of all these methods (see map) which many feel isn’t enough to protect the AONB. What do you think is enough to protect the Chilterns?