This study explores the applicability and effectiveness of electrical resistivity tomography (ERT) as a tool for the high-resolution mapping of submerged and buried shipwrecks in 3D. This approach was trialled through modelling and field studies of Crowie, a paddle steamer barge which sunk at anchor in the Murray River at Morgan, South Australia, in the late 1950s. The mainly metallic structure of the ship is easily recognisable in the ERT data and was mapped in 3D both subaqueously and beneath the sediment-water interface. The innovative and successful use of ERT in this case study demonstrates that 3D ERT can be used for the detailed mapping of submerged cultural material. It will be particularly useful where other geophysical and diver based mapping techniques may be inappropriate due to shallow water depths, poor visibility, or other constraints.

Three-dimensional (3D) modelling is becoming a ubiquitous technology for the interpretation of cultural heritage objects. However most 3D models are based on geomatic data such as surveying, laser scanning or photogrammetry and therefore rely on the subject of the study being visible. This chapter presents the case study of Crowie, a submerged and partially buried barge wrecked near the town of Morgan in South Australia. Crowie was reconstructed using two alternative approaches; one based on a combination of historic photographs and computer graphics and the second based on geophysical data from electrical resistivity tomography (ERT). ERT has been rarely used for maritime archaeology despite providing 3D representation under challenging survey conditions, such as in shallow and turbid water. ERT was particularly successful on Crowie for mapping the external metal cladding, which was recognisable based on very low resistivity values. An alternative 3D model was created using historic photographs and dimensions for Crowie in combination with information from acoustic geophysical surveys. The excellent correspondence between these models demonstrates the efficacy of ERT in shallow maritime archaeology contexts.

Ground penetrating radar (GPR) was used to non-invasively map the location of unmarkedgraves within the Lake Condah Mission Cemetery in western Victoria as a means of siting future interments. This cemetery was associated with the former Lake Condah Mission (established in 1869) and continues to be an important site for local Indigenous people. It is anecdotally thought to contain more than 100 graves however only 26 are currently marked. The GPR survey identified an additional 14 probable unmarked graves as well as 49 other areas that may contain one or more unmarked burials. The extensive subsurface disturbance present at the site and the presence of many extant tree roots made the effective interpretation of the GPR data difficult. Despite this, it was still possible to delineate areas where no unmarked graves are present. This is an important outcome for managing the cultural heritage of the cemetery because it identifies areas where new graves can be emplaced in a culturally appropriate fashion. This demonstrates the utility of GPR as a means of effectively managing heritage sites containing unmarked graves, even when substantial subsurface disturbance is present.