unizeit Schriftzug

Submerged settlements in the Wadden Sea

Using a combination of geophysical and archaeological methods, researchers at Kiel University are looking back to the 14th century and unearthing the history of formerly inhabited areas in the North Frisian Wadden Sea.

Archaeologists push six magnetic field sensors across the mudflats on a trolley
© Ruth Blankenfeldt, ZBS

Archaeologist Bente Sven Majchczack and geoscientist Dennis Wilken push six magnetic field sensors across the mudflats on a trolley. They use them to measure the near-surface magnetic field of the earth and can thus reconstruct the submerged cultural landscape from the Middle Ages.

Back in the 14th century, what are now the island of Pellworm, the peninsula of Nordstrand and the Nordstrandischmoor Hallig (undyked islet) formed a single connected landmass criss-crossed by lots of small watercourses. There were several settlements here, including the medieval trading centre Rungholt, as well as fertile arable land. This land was gradually lost to storm surges. The beginning of the end was the devastating storm surge of January 1362. It went down in history as the “Grote Mandränke” (Old North Frisian for “Great Drowning of Men”), taking settlements and arable land with it. All we know from records passed down from this time was “that 42 parishes are said to have been lost as well as the legendary Rungholt,” explained Kiel-based archaeologist Dr Bente Sven Majchczack from the Cluster of Excellence ROOTS. “What was left of the medieval cultural landscape was swallowed up by the second “Grote Mandränke” of 1634, leaving just Pellworm and Nordstrand behind. More than 6,000 people are said to have drowned then, which was two thirds of the population there.”

As members of a larger research network, Majchczack and his colleague Dr Dennis Wilken from the working group Applied Geophysics are tracing the remains of the submerged settlements. Their objective is to understand how people lived there and how they dealt with natural disasters. The investigations form part of the research project RUNGHOLT, which is now in its second phase being funded by the German Research Foundation (DFG). Project partners are the Johannes Gutenberg University Mainz and Kiel University, the Centre for Baltic and Scandinavian Archaeology (ZBSA) and the Schleswig-Holstein State Archaeology Department (Archäologische Landesamt Schleswig-Holstein) in Schleswig.

During the first phase of the project, the researchers from Kiel and Mainz developed methods to research the remains of settlements submerged in the tidal flats and produced an initial reconstruction of settlement structures. Magnetic gradiometry is an important method for taking measurements. “At low tide we drive a vehicle fitted with six magnetic field sensors over the tidal flats and measure the earth's magnetic field close to the surface. From this we produce maps that clearly show the structures of the dykes, drainage ditches and field boundaries,” explained Dennis Wilken from the Institute of Geosciences. This study is supplemented by seismic measurements taken at high tide. Wilken explained that “In principle, this works like an echo sounder that penetrates into the sediment. We can use this to create a vertical cross-section and break down the changed soil structures. If we drill bores at points of interest, we can say exactly what we have there.” The drill cores are then taken to be analysed at Johannes Gutenberg University Mainz.

map of a part of the wadden sea
© pur.pur

A particular challenge of this project is the work carried out which is dependent on the tides. Majchczack said that “There is always a very short time frame. When the tide is going out, first you have to get to your area of work and then you have two and a half or three hours to get the work done. And then you have to make sure you get back before the tide comes in again.” Traditional archaeological fieldwork is only possible where the finds have been excavated, he added. “Of course, the areas where this works are very limited. In 90 percent of tidal flat areas we can only make progress through geophysics and drilling bores.” This is why there has not yet been any systematic research into these submerged medieval landscapes in the tidal flats. The methods for this research had to be developed first, said the archaeologist. “We are only now getting to the settlement remains covered in sediment.”

The medieval losses are especially interesting, he said, because hardly any records have been passed down on these. “We do not know exactly how large this lost landscape was, how the settlements looked, how people farmed or, above all, what people did back then to claim and secure the landscape,” said Majchczack.

Initial findings were made in the preceding project, reported Wilken. “We were able to reconstruct where the dyke ran, how the dwelling mounds were connected to the dyke and where fields and pathways were laid out in our area of investigation. In the vertical cross-section, for example, we see that the dyke in this area was higher than the connected dwelling mound. This means that when the dyke broke, the dwelling mound, i.e. the hill on which the houses were built, flooded.”

Author: Kerstin Nees