Cognition has been commissioned by Linden Homes to undertake a programme of remediation works on a brownfield site at River Lane, Fetcham. The eventual site redevelopment will include the construction of 26 new homes and the improvement of drainage and flood risk mitigation systems. An additional feature will be the creation of landscaped and managed wildlife areas for recreation and to enhance the local ecology. It is envisaged that the project can help restore the “Green Belt” characteristics of the area.

In recent years, the site has had several users including a nursery, tyre yard and topsoil manufacturer. This has resulted in a diverse array of remedial work being required prior to the commencement of the redevelopment project. Once Cognition has completed the remediation works, the site will be handed back to Linden Homes to begin the redevelopment.

The site will be divided into 5 zones which will comprise different end uses; public open space, housing units and a wildlife buffer zone. Prior to the main works commencing, Cognition will carry out the removal and burial of the invasive Japanese Knotweed that is prevalent across the site and divert the stream to reduce the risk of contamination during the remediation works. The demolition and breakout of existing structures will then take place and clean soils will be excavated and stockpiled for later reuse as clean cap for landscaped areas. Next, hydrocarbon contaminated soil and made ground will be excavated, treated with bioremediation techniques, or disposed of as necessary, with the aim of reusing as much material as possible on site. The soils will also be tested for the presence of asbestos fibres and the necessary compliance measures followed.

The works will conclude with the construction of a fully engineered pile mat using stabilised material that has undergone geotechnical testing, and finishing off the landscaped areas with a clean cap.

Cognition will follow a rigorous environmental monitoring plan, to ensure that risks to the local public and environment surrounding the site are strictly controlled and disruption minimised.