Rapid Archaeological Site Surveying & Evaluation in the Marine Environment and Transistional Zones

English Heritage ALSF summaries. 2004/2005

The RASSE project was a three year research project undertaken by the University of St Andrews with partners, funded by Round 2 of the Marine Aggregates Levy Sustainability Fund (MALSF) administered by English Heritage (EH).  The principal aim of the project was to test and develop rapid and quantitative, remote (geophysical) sensing techniques for the enhanced investigation of maritime archaeological sites in aggregate extraction areas.  Furthermore, the project attempted to improve temporal and environmental assessment methods for sites and areas of high archaeological importance.  The project addressed issues of direct relevance to the aggregate industry, to managers and curators of the marine historic environment, and to academia.  The work complemented Round 1 and 2 ALSF funded projects administered by EH such as those by Wessex Archaeology and the University of Southampton.

The project involved analysis of historical data sets and the construction of a test site in Plymouth Sound to enable development of protocols to maximise the potential of geophysical techniques for monitoring submerged archaeological sites. Advanced processing (software) methods including ‘scale saliency’ and ‘scale invariant feature transform’ techniques were tested for automated object recognition on the Hastings Shingle Bank and the wreck Stirling Castle, which sank in 1703 on the Goodwin Sands.  This important historic wreck has been extensively surveyed using a range of acoustic techniques since 2002.  The RASSE project collected a further four ultra high resolution data sets using a Reson Seabat 8125 sonar. By comparing each, it was possible to identify changes in the elevation of the seabed and to attribute changes to real effects, i.e., the movement of sediment.  Furthermore, it was also possible to monitor changes (deterioration) within the wreck site resulting from the wreck exposure.  As a result of initial investigations, a new spar buoy deployment system (the independent sonar head attitude and positioning system – ISHAP) was designed for the multibeam sonar.  Tests with this new system demonstrated a significant increase in the fidelity of the data recorded thus giving far higher resolution images of archaeological remains on the seabed.

The RASSE project has demonstrated that advances in acoustic processing techniques have the potential to improve our understanding of seabed archaeology, by offering enhanced discrimination of archaeological material. Furthermore, the high resolution acoustic techniques have been shown to provide an effective and efficient tool for investigating, monitoring and quantitatively evaluating large and small changes on a marine archaeological site. The results are sufficiently detailed to allow curators to understand and measure the impacts to archaeological sites that can arise from a complex interplay of natural and man-made ‘drivers of change’.

In the final analysis, sound data enables sound decision making. In light of this, we recommend that these techniques should be routinely used both for wide-area and detailed archaeological site investigations. The results will provide crucial information for the long-term management of change within the submerged archaeological resource in UK coastal waters, and in the context of increasing pressure from aggregate extraction and other commercial and recreational activities.

This page was published on 17/09/2007