08-05-2025

Eichstätt geographers in search of Roman bridge and harbor remains on the Moselle river

The Department of Geography at the KU is helping archaeologists in their search for ancient Roman bridge and harbor remains in Trier. Because it is not possible to search for ancient remains at the bottom of the Moselle with shovels, scrapers and brushes as usual and divers would not see anything in the murky water, the KU research boat has now been deployed. It is equipped with state-of-the-art technology: Using a multibeam echo sounder, the bottom of the water can be surveyed so precisely that even the remains of former bridge piers or remaining piles are visible as elevations.

KU geographer Prof. Dr. Florian Haas usually takes his research boat to mountain lakes in the Alps to investigate the quantities of debris that melting glaciers carry down into the valley. The motorboat has now spent four days on the Moselle on behalf of the Department of Provincial Roman Archaeology at the University of Trier. Together with underwater archaeologist Dr. Max Fiederling from the Transmare Institute at the University of Trier and archaeologist Ronja Fink, they used an echo sounder to examine the structures at the bottom of both rivers.

The method used is called bathymetry: This creates a topographical model of the river bed – with a level of detail of 25 measuring points per square meter. This revealed structures in the subsoil that indicate old bridge piers. These remains, which lie directly next to the Roman bridge that exists today, can be assumed to be the pillars of the first Roman bridge from 17 BC, explains Florian Haas. The echo sounder also revealed the remains of suspected boat docks. However, detailed investigations at the site would have to clarify whether these are actually Roman remains of port facilities or docks.

Trier, the oldest city in Germany, was once the capital of the western Roman provinces with numerous Roman villas along the Moselle. The Romans traded there – also with ships. But where were the ancient harbors and bridges located? Some bridge locations are known, others are merely suspected. All we know about the docks and harbors is that they must have existed. Wine, stone from quarries and other goods were certainly transported by ship across the Moselle and on to the Rhine.

Archaeologist Ronja Fink drops a sonic probe into the river

The contact between the Trier archaeologists and the Eichstätt geographers was established at a conference on Roman roads, which was organized at the KU by the departments of Ancient History and Classical Archaeology and in which Trier scientists also took part. Following the deployment of the KU research boat, the river bed in the urban area of Trier has been fully mapped. Now the data will be evaluated. However, it will be a few more weeks before these are finalized and handed over to the archaeologists in Trier, says Florian Haas. "We are all already very excited to see whether there will actually be finds that will help archaeologists in their research into the trade routes of the Provincial Romans."