Underwater archaeology is becoming less and less dependent on diving. Today, hydrographic technologies are playing an increasingly important role, allowing us to see what is hidden beneath the seabed – non-invasively, precisely, and across the entire research area. This is the subject of our latest scientific article published in the Journal of Applied Hydrography, prepared jointly by specialists from INNOMAR and researchers from the Centre for Underwater Archaeology at Nicolaus Copernicus University in Toruń. The article shows that modern hydroacoustics is no longer an addition to underwater archaeology, but one of its most important research tools.
Satisfactory research results
The publication concerns research on the medieval port in Puck — one of the most important underwater archaeological sites in the southern Baltic Sea basin. As part of the project, we used the Innomar SES-2000 quattro parametric, multi-transducer sub-bottom profiler to image structures beneath sediment layers. The results were very gratifying: we managed to identify a buried shipwreck, determine the extent of the medieval port area, and trace the paleochannel of the Płutnica River within Puck Bay. This is exactly the type of data that allows us to look deep into the sediments where divers cannot reach.
Picture: Jens Lowag
Methodology with prospects for the future
What is particularly important is not only the result itself, but also the methodology. The research was conducted in very shallow water, in places only 1–3 metres deep, i.e., in conditions challenging for both archaeologists and hydrographers. The system used enabled the collection of a dense, high-resolution 3D dataset with a 1-metre profile grid. During approximately 35 hours of work, nearly 700 short measurement lines were obtained, covering an area of approximately 0.13 km². Sediment penetration of up to approximately 3 metres and vertical resolution better than 10 cm were achieved. In practice, this means that it is possible to capture the subtle relationships between archaeological objects, harbour sediments and the former terrain.
Picture: Jens Lowag
Cooperation is the key to success.
This is where the importance of cooperation with INNOMAR becomes apparent. INNOMAR is a manufacturer specialising in parametric sub-bottom profilers for imaging structures below the seabed, and the "quattro" model was designed specifically for applications requiring very high data density in extremely shallow waters, including archaeological research. The company also emphasises that INNOMAR solutions are developed with the imaging of objects and structures hidden in the sea and river beds in mind. In our project, therefore, it was not merely a cooperation on equipment, but a real combination of archaeological and hydrographic expertise that translated into scientific and practical results.
Hydrography and archaeology
For us at the Centre for Underwater Archaeology at Nicolaus Copernicus University, hydrography must be used not only for mapping the seabed. We treat it as a cognitive tool that allows us to detect objects buried under sediments, reconstruct former coastlines, identify the boundaries of ports, quays and areas of waterfront use, and then combine this data with the results of diving surveys, photogrammetry and other documentation methods. In the project described, data from the sub-bottom profiler were interpreted alongside results from other studies, including multibeam measurements and photogrammetric documentation. It is this integrated approach that sets the standard for modern underwater archaeology today.
Cooperation and investments
It is no coincidence that we focus on such projects at the Centre. Underwater sites are becoming increasingly complex, and much of the most valuable information is not on the surface of the seabed but hidden in sediments. If we want to study them responsibly, effectively and without unnecessary interference, we must use the most advanced hydroacoustic tools available to science. We have invested in our own multibeam echo sounder and are developing cooperation with leaders in the hydrographic community in Poland and Europe. Our latest article shows that we are not only able to implement these technologies, but also to use them creatively to solve real archaeological problems.
Directions for development
Our article is not just a presentation of one case from Puck. It is also a clear signal of the direction in which contemporary underwater archaeology is developing: towards increasingly precise, non-invasive research based on data sharing and close interdisciplinary cooperation. And it is in this direction that we want to develop further projects carried out by the Centre for Underwater Archaeology at Nicolaus Copernicus University.