Sašo POGLAJEN
(University of Primorska, Piran, Slovenia)
The contribution presents a practical account of the techniques and procedures for bathymetric measurements, which can be applied for the benefit of underwater archaeological investigations. The procedure for measuring using a single beam sonar is technically much simpler than the more advanced procedure based on measuring with a multi beam sonar. A comparison of the two procedures will be presented as applied on measurements of select Roman underwater structures along the coastline of the Slovenian shore. The underwater structures at Jernejev zaliv and at Fizine near Portorož were measured using a single beam sonar. The Roman pier at Simonov zaliv and structures at Jernejev zaliv were documented using a multi beam sonar. The latter facilitates a more precise bathymetric system, which at small depths enables an impressive encompassment of details from which maps can then be compiled. This system certainly proffers the best solution for documenting underwater structures, however due to the advanced technology it necessitates and the fact that it needs to be mounted on a larger vessel, it is not always accessible or appropriate for use in shallow, shoreline waters, which is where the majority of underwater Roman structures are positioned. The single beam sonar, which is mounted on a smaller vessel and which allows for recordings to reach all to the coastline, is almost ideal for bathymetric measurements of the shoreline tract.
Keywords: underwater archaeology, bathymetric survey, roman pier