Linden Homes South East appointed JNP Group as their environment consultants on a new housing development at a former car garage site in Teddington, Middlesex.
JNP’s role was to undertake further ground investigation, design a remediation strategy and supervise the validation work at the above site. The site comprised a former two storey office with above and underground fuel tanks. The Made Ground at the site had been impacted with metallic and hydrocarbon contamination; isolated areas of asbestos had also been identified.
The development comprises a mix of two and three bedroomed terraced town housing with private gardens and areas of car parking; an apartment block in the south east with an underground car park; and an area of public open space in the central part of the site.
During the investigation work, the underground fuel tanks were found to have leaked into the surrounding natural ground of the Kempton Park Gravel Formation. Further investigation was undertaken to delineate the extent of this hydrocarbon plume.
Contaminated Made Ground and the hydrocarbon impacted natural ground was removed off site and transferred to a soil treatment facility, negating the need for capping layers in the areas of private gardens and public open space.
In addition, as a result of the requirements in final ground level at the site, a substantial amount of natural ground was obtained and following regulatory approval (and to avoid the use of importing fill from elsewhere) this was re-used on site.
Final validation work is still being undertaken at the site. The development will comprise 58 new dwellings built on a brownfield site using a sustainable development scheme.
JNP Group services provided:
- Several phases of intrusive ground investigation.
- Delineation of hydrocarbon plume.
- Generic human health and controlled waters risk assessment.
- Gas risk assessment.
- Refinement of conceptual site model.
- Production of a remediation strategy.
- Liaison and negotiation with the Environmental Agency, London Borough of Richmond Upon Thames and NHBC.
- Validation of the natural ground and topsoil.
- Production of a validation report.