Bourn Airfield, Cambridgeshire

Countryside Strategic Land & Major Projects

As a result of our close working relationship with the client, IDOM Merebrook were asked to provide a detailed appraisal of risks at this 282 hectare former airfield site which is to be redeveloped to provide a new village including homes, community facilities and commercial premises.

Following an initial risk appraisal based on a review of existing data, we designed and completed a supplementary investigation. Given the former use of the site, close attention was paid to emerging contaminants perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). These substances are highly persistent in the environment earning them the name of “forever chemicals” and they are linked to a range of adverse health effects. Explosive residue testing was also carried out due to historical weapons storage on the site identified from mapping.

Our investigation proved the absence of significant contamination resulting from the former use of the site meaning that site-derived topsoil could be re-used on site thus minimising the volume of material required to be imported to site.

  • Review of desk study and ground investigation reports produced by others
  • Intrusive ground investigation including:
    • Shallow boreholes to determine geotechnical properties of soils;
    • Runway cores to test for the presence of asbestos and coal tar;
    • Installation of hazardous gas monitoring standpipes;
    • Trial pits;
    • Infiltration testing to the BRE Digest 365 Soakaway Design Standard;
    • Lightweight deflectometer to measure the bearing capacity of shallow soils;
    • UXO watching brief
  • Conceptual model and Tier 2 generic quantitative risk assessment
  • Preliminary geotechnical recommendations for road, drainage and foundation design
St Christophers