Since Planning Policy Guidance 16 (PPG 16) came into force, local authorities have the power to place a constraint order on any planning application where they suspect archaeological features may exist until their presence or absence has been determined.
If remains are found they must be left undisturbed or excavated and recorded to a standard set out by the planning authority - all of which has major financial and time implications for developers.
However, early use of geophysics to assess a site can inform the design process before submission and minimise the potential conflict between development and archaeological remains.
Leeds based Met Surveys was recently asked to locate the position of graves in a 19th Century churchyard so a proposed extension could be designed.
Graves are notoriously difficult to locate because they are commonly backfilled with the same material that was excavated, and once the backfill material has compacted over time contrast can be slight.
In this instance, the local igneous geology also meant the site was unsuitable for a magnetic survey, so ground penetrating radar (GPR) was chosen.
The GPR was undertaken on a 0.25m by 0.25m grid, and located a number of areas where the ground has been disturbed, as well as possible coffins. While it was not possible to determine the origin of all the anomalies or graves in the site, the survey did highlight areas to avoid and others where care should be taken during excavation.
'Geophysical techniques not only aid archaeological investigations, they can actively help developers achieve planning consent, ' says Met Surveys' senior geophysicist Mark Whittingham. 'This may not totally avoid the need for excavation, but it will give an accurate indication of archaeological potential and so can be used to determine likely cost and time implications if archaeology is found.'