Met Unearth Treasure For Developers

When brownfield redevelopment threatened a long lost archaeological site, the local authority and developers turned to 21st century surveying technology to help find it again.
Though it was generally known that a 12th century manor house and moat had once existed in the area, their precise location had long since been lost and buried, most recently beneath several metres of industrial landfill dating back as far as the 1930's.

Met Surveys were commissioned to carry out a ground penetrating radar (GPR) survey of the brownfield site ahead of redevelopment. The survey was able to reveal the location, profile and dimensions of the moat, including information on the minimum depth of the infill material, as well as potential structural or foundation issues associated with the manor house.
Met carries out GRP Technology to Locate the 12th Century Moated Manor House
Now that the exact location of the site was known, archaeological excavation could be undertaken. Once the extent and preservation of the remains have been finally established, it is intended that the moat and any structural remains associated with the manor house will be preserved in situ, by being incorporated into the development design.

"Geophysical techniques not only aid archaeological investigations, they can also help developers achieve planning consent and avoid the costly implications of an 'unexpected' find," says Mark Whittingham of the Met Surveys Geophysics Division.

Since the introduction of Planning Policy Guidance 16 (PPG 16) in 1990, archaeology has played an increasingly prominent role in planning consent for developments.

Most county councils and unitary authorities now employ Development Control Archaeologists to advise the planning department on the archaeological implications of proposed developments and on the basis of that advice may place a constraint order until the presence or absence of archaeological features has been determined.

If remains are found they must either be left undisturbed or, more commonly, be excavated and recorded to a standard set out by the planning authority.

Archaeological constraints are rarely imposed until a planning application has been submitted, at which point it is often too late to amend design solutions to avoid the remains and so excavation and recording usually have to be undertaken - all of which has major financial and time implications for developments.

Costs can vary from several thousand pounds for excavating small trial trenches where there are no important features, to in excess of £100000 for an archaeological site of regional importance which can take several months to excavate and record.

"The best way to avoid unexpected delays late in the design process is to assess a site as early as possible," says Mark Whittingham. " In archaeological terms this can be achieved by a geophysical survey. It may not totally negate the need for excavation but it will give an accurate indication of archaeological potential and hence can be used to determine likely cost and time implications if archaeology is found."

If undertaken early enough the results of a geophysical survey can also be used to amend the proposed design such that the impact on archaeological remains, and hence the cost of excavating them, can be reduced.

The most cost-effective way of assessing a site for archaeological potential is to carry out the work at the same time as other subsurface investigation techniques are being applied. If a geophysical survey is required to identify buried utilities for example, or mineshaft location, then it may be possible to use the same techniques to provide information on the possible presence of archaeology.

Conversely, if it is known that an archaeological geophysical survey has to be executed anyway, carrying it out at an early stage in the project design may provide geotechnical information that can be used in the design, such as identifying areas of made ground, or subsurface structures and other features.