RPS’ Sydney-based Cultural Heritage and Subsurface Survey teams have joined forces to uncover links to one of New South Wales’ most famous colonial administrators – Governor William Bligh.
RPS in search of colonial history
The team was engaged by Johnson Property Group to assess the heritage values of an 8.8 hectare site at Pitt Town that once belonged to the Governor. Earmarked by the client for residential sub-division, the site is believed to have formed part of ‘Blighton Farm’, a place of great historical significance for the state.
Blighton Farm was established as a model for farming in the new colony and formed a backdrop for key events of the time, such as the Rum Rebellion of 1808, where Bligh was deposed as Governor in a military coup.
RPS’ Cultural Heritage team was engaged to undertake excavations of the site to locate any archaeological artefacts remaining, however after years of agricultural activity, landfill dumping and clearing, there were no longer any historical landmarks above ground to guide the team’s search.
In view of this challenge, the team consulted with their RPS Survey and Mapping colleagues to develop a strategy for scanning the extensive area and identifying priority areas for excavation.
High-tech methods for historical investigation
Ground Penetrating Radar (GPR) was used to uncover five significant features below the ground where the Cultural Heritage team would initiate archaeological digs.
GPR technology has not been widely used for cultural heritage investigations in Australia, due to the cost and limited availability of GPR equipment, and the margin for error presented by conductive soil composition in areas such as New South Wales.
To overcome these issues, a geophysical detection strategy was developed whereby the efficacy of the GPR would be tested (using a hand-pushed GPR scanner) before being deployed over the larger area on a mower-mounted rig.
A Mala Imaging Radar Array (MIRA) – the most technically advanced GPR system on the market – was used to ensure the most accurate possible outcome in the least amount of time. The unit features 16 channels in one unit allowing for “one pass” 3D mapping over large areas, and seamless integration of acquisition, processing, quality control, positioning data, interpretation and export of GPR data.
The data gathered was then analysed by the survey team to identify the exact locations of underground objects or anomalies. RPS surveyors could then accurately mark areas for excavation by the Cultural Heritage team.
Finding history in the haystack
The innovative spatial technologies and methods adopted for this investigation allowed our team to uncover important links to New South Wales’ past. The footings of a brick outbuilding were discovered which may be the only physical evidence of Hawkesbury region’s first farms established in the 1790s.
While definitive links to the Governor weren’t found, the bricks uncovered were hand made, and many of the additional artefacts found are contemporary to Bligh, including eight coins dated between 1797 and 1827.
Both teams are excited by what this investigation means not only for the history of the Hawkesbury region, but for other cultural heritage investigations to come. By combining RPS’ capability in subsurface detection with our archaeology and heritage expertise, historical artefacts were discovered that otherwise may never have been found.
The use of GPR spatial technology also allowed the investigation to occur much faster than traditional test excavation methods, with the digs completed in just three days.
RPS’ investigation was as a finalist in the NSW Excellence in Surveying and Spatial Industries Awards in the ‘Spatial Enablement Category’.