An ambitious plan to create extensive areas of new ecologically rich habitat in the Colne Valley using excavated chalk from HS2 tunnelling under the Chilterns has been approved by Three Rivers District Council and Buckinghamshire Council.
The proposals, led by LDA Design and Jacobs as part of the Align joint venture, represent the biggest single landscape and habitat creation scheme within HS2’s Green Corridor programme. It will create 127 hectares of calcareous grassland, broadleaf woodland, pasture and wetlands.
The project will also benefit local communities by providing around 4.5km of new footpath, cycling and horse-riding routes with connections into the Colne Valley Regional Park and the neighbouring Chilterns Area of Outstanding Natural Beauty.
The scheme re-uses three million tonnes of excavated chalk from the 10-mile tunnel to form a series of shallow valleys. It is just one of several initiatives to reduce locally the project’s carbon footprint.
HS2 is also looking to recycle construction waste such as concrete and aggregates within the soil profiles and has commissioned Cranfield University and soil experts Tim O’Hare Associates to undertake research and trials.
Simon Railton, a director at LDA Design and landscape architecture lead, says this is a significant milestone for the project.
“Our ambition is to create an immersive place for people to connect with nature,” explains Simon, “a mosaic for hundreds of species of flora and fauna, many of which are scarce or under threat. In addressing important matters such as biodiversity loss we hope to provide an enduring legacy for the project.”
The first of two tunnel boring machines began excavating the tunnel earlier this year, with the site now set to receive a continuous supply of chalk until tunnel completion in 2024. Field trials are in preparation ahead of final seeding, and planting of trees and shrubs in 2025.
Working with LDA Design and Jacobs in the Align JV are three international infrastructure companies: Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.