The transformation of HS2’s largest construction site into a haven for wildlife reached a major milestone last month, with the millionth cubic metre of chalk laid out around the south portal of the Chiltern Tunnel, near Amersham and Chalfonts.
The ambitious environmental project will eventually see 2.6 million cubic metres of chalk excavated during the construction of the 10-mile-long tunnels used to create one of the largest areas of chalk grassland in the Chiltern Hills.
Two giant tunnelling machines – named Florence and Cecilia – are currently miles deep into their journey under the Chilterns.
Instead of removing the unearthed chalk by road, it is being used to landscape the site as part of plans to create 127 hectares of new chalk grassland, woodland, wood pasture and wetland habitats.
The Chiltern Tunnel will be the longest tunnel on the HS2 route between London and Crewe and will pass beneath Amersham and Chalfonts.
HS2 Ltd’s environment director Peter Miller said: “The south portal project is one of the most important parts of our Green Corridor programme to establish better connected, sustainable and biodiverse landscapes along the route of the new railway.”
Chalk grassland holds little water and drains well, creating conditions which encourage a huge variety of herbs and wildflowers.
Around 4.5km of new footpath, cycling and horse-riding routes will give the public access to large parts of the site.