Desk-Based Assessment

The best way to assess the impact that a development project may have on archaeologically important sub-surface deposits is by means of a geoarchaeological Desk-Based Assessment (DBA).

ARCA has long and extensive experience of producing geoarchaeological DBAs for a variety of clients (archaeological contractors, environmental consultancies, national heritage agencies, local authorities and utility companies).

A geoarchaeological DBA is a written report that draws together geological data, topographic information and records from prior geotechnical and archaeological investigations, all meant to provide an initial assessment of the geoarchaeology of the site.

The principal source of data is often British Geological Survey (BGS) mapping (superficial and drift geology), the BGS borehole database and, where available, stratigraphic data from prior geotechnical and archaeological investigations of a site. However, non-geological data are also important in assessing the likely sub-surface stratigraphy, particularly topographic maps such as those produced by the Ordnance Survey, aerial photographs (for example as available via Google Earth), and, for some locations, multispectral satellite imagery.

When we integrate of all these data sources within Geographic Information Systems (GIS) software and specialist geological software, we can produce interpretive cross-sections, deposit models and predictive models, which illustrate the impacts that development work may have. An accompanying text explains the deposits present on a site and how those determine its archaeological potential. The geoarchaeological DBA report can then be used to inform what (if any) archaeological works are required and how possible damage to sub-surface remains might be mitigated.