The building site where the HS2 railway dips into a tunnel under the Chilterns is to be turned into a large nature reserve once the construction works have finished.
The site, which was a number of monoculture arable fields sits just inside the M25 motorway and is currently being used to start construction of the two tunnels that run under the Chilterns.
At the moment, it’s a huge building site, and they were always required to restore the landscape afterwards, but rather than returning it to fields, they’re taking an opportunity created by the tunnels themselves to create a nature reserve instead.
The tunnels are digging through a chalk landscape under the Chilterns, and that spoil needs to be removed, but by using it to landscape the local area by the tunnel mouth instead they are both reducing the amount of traffic needed to remove the spoil, but also creating a chalk rich reserve.
Around 3 million cubic metres of chalk from the tunnels, along with soil from the construction site will be piled up into new hills and slopes around the HS2 railway to create a chalk valley landscape.
Calcareous grasslands, which develop on shallow soils overlying chalk or limestone, are a valuable, scarce and rapidly declining habitat in the UK, with this decline reflected in both the Colne Valley and adjacent Chiltern Hills.
The neighbouring Chilterns Area of Outstanding Natural Beauty is currently thought to support around 700 hectares of chalk grassland, and at 90 hectares, the HS2 site will increase that by nearly 13 percent.
In addition, nearly 65,000 trees and shrubs of 32 species will be planted together with nearly 3.5km of new hedgerows. The loss of hedgerows, mainly in arable farms, has been identified as a factor in the decline of many plant and animal species in the UK.
In total, the new nature reserve will be nearly 130 hectares in size and will include around 4.5km of new footpath, cycling and horse-riding routes.
Those who hate HS2 will never stop hating it, but the question at this stage should be less about trying to stop HS2, as that ship has long since sailed, but maximising the various opportunities that it can bring, or if you prefer another way of putting it, minimising the downsides.
This is one site where once there was bland arable fields next to a noisy motorway, but in a decade’s time will be a thriving haven for wildlife.
Tunnelling at the Chiltern portal is set to start shortly and should be completed in 2024. Field trials are in preparation ahead of the final seeding, and planting of trees and shrubs in 2025.