During excavations in the Merwede Canal zone in Utrecht, archaeologists found evidence of a massive flood that caused significant damage to the infrastructure of Roman Netherlands shortly after the year 100. The disaster swept away a bridge, leaving a 10-meter deep whirlpool behind. The research in the Merwede Canal zone over the past months has yielded numerous new insights into the development of the Roman border (limes) in the Netherlands.
Flood and Delta Plan
The bridge collapsed around the beginning of the second century during a major flood, creating a 10-meter deep whirlpool. In the year 125, a large restoration campaign followed. A 140-meter long detour was constructed around the whirlpool, with a heavy oak wood revetment. Elsewhere in the Rhine Delta, the infrastructure was also rebuilt to a high standard. This delta plan seems to have been executed at the behest of Emperor Hadrian, who had visited this area during an inspection trip a few years earlier, said municipal archaeologist Erik Graafstal.
The driven wooden piles along the Roman road from around 125.
Hundreds of Wooden Piles
During the research, many hundreds of wooden piles were recovered. Besides some bridge pillars, these include revetment piles from bridge heads, culverts, and the sides of the road. The exceptionally well-preserved wood remains contain a wealth of information about origin, logistics, and construction history. It appears that the oak wood for the delta plan of 125 came from the northern Ardennes. It is expected that ring-width research will yield even more new data about the development of the limes. Volunteer archaeologists are helping to clean the enormous amount of wood.
Volunteers carefully clean the Roman wood with a sponge, preserving the processing marks in detail. Photo Abe Jonker.
Roman Water Management
The excavations focus on the A1 of Roman Netherlands, the military connection route that linked all forts and watch posts along the limes. In December of last year, the branch towards the Dom Square was already discovered here. The border of the Roman Empire was formed here for the Rhine, which then flowed through Utrecht. The Romans had to pay their tuition in this dynamic river delta, but ultimately they arrived at clever forms of water management. For example, the archaeologists found various types of culverts in the Merwede Canal zone, allowing floodwater to drain into the hinterland under the road. Erik Graafstal: “But the most remarkable is a possible 35-meter long marsh bridge. This allowed the limes road to cross a natural depression that was susceptible to flooding. All these works were built by the Roman army.”
Visualization of the bridge belonging to the first phase of the limes road.
Rachel Streefland, councilor for Heritage: “Thanks to archaeology, we learn about Utrecht and its surroundings in earlier times. This remarkable discovery once again shows how important archaeological research is. What we learn from archaeological research can then be used in the further development of the city, which strengthens the bond of residents with Utrecht. Thus, heritage connects the past with the present.”
A Gaping Hole
After the disaster around the bridge, a deep water pool remained with a diameter of 45 meters. Passersby occasionally made offerings at the eerie whirlpool during Roman times, including a unique silver necklace. It took many centuries before the hole was filled with peat and clay. This soft filling has led to subsidence up to the last century. The majority of the whirlpool, along with everything that may still be in it, remains preserved in the soil as a treasure for future generations. A section of the detour from the year 125 also remains preserved underground.
A silver belt necklace and military belt fittings inlaid with glass paste from the whirlpool.
Innovation Lab
In the Merwede Canal zone, a new urban district Merwede is being built. The research is being conducted on behalf of the developing parties Greystar, G&S/Boelens de Gruyter, Orion Investment Partners, and Portaal. This large-scale development is the first in the Netherlands to work with its own innovation lab, where not only future innovations are produced but also much attention is paid to heritage experience. “History plays a crucial role in strengthening the identity and connectedness of urban areas, but in the current Merwede, unfortunately, very little of the rich past of the area can be seen. Therefore, we find it important to make the past of Merwede visible and experiential. We are also incredibly happy with this beautiful find that underscores how special the Merwede Canal zone is in the history of the Netherlands,” says Elies Koot, developer at Boelens de Gruijter.
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