Heathrow Expansion

DateOct 25, 2016

The Heathrow expansion has been a hot topic for many years and still divides political opinion, with even the Prime Minister's constituency fighting the expansion. However this morning we saw ministers approve the long-awaited decision, with Chris Grayling Transport Secretary calling the decision “truly momentous”.


Whilst most commentators are now concentrating on what’s going on up in the skies and on the ground, Groundsure took a look at what lies beneath, examining the environmental hazards that the 573ha expansion of Heathrow could unearth. The geology beneath the expansion area comprises superficial deposits of Shepperton Gravel Member and Taplow Gravel, amongst others. This geology meant that, historically, these areas were used for sand and gravel extraction, leaving large pits subsequently used for waste disposal.

Initial analysis shows that approximately 27.3% of the land beneath the proposed Heathrow footprint (excluding land already developed as part of Heathrow) was formerly used as landfill, with a further 12.3% classified as active landfill. Additionally, historical land uses such as breaker’s yards, factories, transport depots, garages, old gravel pits, electro-chemical engineering works and saw pits can be found at the site, all of which have the potential to have left legacies of contamination which would require some form of investigation and possible remediation. Groundsure’s historical land use database shows that approximately 22.4% of the development area was formerly used for industrial purposes.

A report commissioned by Gatwick Airport and produced by RSK Group claims that the cost of clearing these landfill sites and associated contaminated land would be an extra £500m[1], far more than the cost of the cleanup of the heavily contaminated Olympic Park (c.£386m[2]). However, given that the Olympic Park was only around 246ha in size, the per hectare cost for remediation of the Olympic Park was £1.56m, as opposed to £872,600 as an equivalent per hectare cost for Heathrow based upon RSK’s projected costs.

Heathrow’s own projections show that only £130m has been set aside to mitigate all environmental concerns[3] (including reprovision of wildlife habitat, flood mitigation and reprovision of reservoir costs). It is not clear whether this accounts for necessary environmental remediation, or whether this is accounted for in the £17.6bn estimate for general ‘airport infrastructure’. If the £130m does include the costs for investigation and remediation, it would seem that Heathrow have grossly underestimated the costs associated with land contamination, and will be digging into contingency funds before a brick is laid.

In addition to the brownfield legacy of the proposed development, there is also the issue of greenbelt development, given that the vast majority (approximately 78%) of the development area lies within the London greenbelt, whilst also cutting into a small part of a designated Local Nature Reserve. However, given that around half this greenbelt area is also brownfield land, it is not hard to imagine the arguments that could be made in favour of development, despite simplistic policy assessments in the Conservative manifesto which appear to imply that greenbelt and brownfield land are mutually exclusive entities[4], and also the a priori assumption that brownfield land always has an lower ecological value than greenfield sites.

Whilst the decision to build has been approved, there are likely to be significant legal battles before a final “final” decision is reached. “Don’t book your opening ceremony tickets just yet” (Simon Calder)



[1] http://www.colnbrookcommunityassociation.org.uk/landfill-clear-up-would-add-500m-to-heathrow-runway-cost/

[2] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/78228/DCMS_GOE_QR_JUNE-2012.pdf

[3] http://www.heathrowairport.com/static/Heathrow/Downloads/PDF/a-new-approach_LHR.pdf

[4] http://issuu.com/conservativeparty/docs/ge_manifesto_low_res?e=16696947/12317396