Hidden beneath Cologne’s bustling streets flows a river with a rich history. This is the Duffesbach. Its origins lie in Hürth-Knapsack. The Duffesbach is unique. It’s the only stream in the Cologne Bay that reaches the Rhine. This is because the Romans engineered it. They created an artificial waterway. This supplied water to Cologne’s medieval guilds and businesses. Before this clever intervention the Duffesbach disappeared into the gravel. This was west of Cologne between Kalscheuren and the Militärring. Sediment proves this surprising fact.
The Duffesbach’s journey wasn’t always straightforward. Its course changed over time. In earlier times it had different names. In Cologne it was known as the Gleueler Bach or simply ‘die Bach’. The street that followed its path is called Kölner Bäche. Before entering Cologne it was mostly called the Hürther Bach. The name Duffesbach itself is unclear. Attempts to link it to tuff mills or a dovecote haven’t yielded definitive answers.
The Duffesbach once powered many mills. There were seven mills in Hürth alone. A malt mill stood near its mouth in Cologne. These weren’t typical mills with ponds. Water was briefly dammed in the mill stream itself. Mills could only operate if those upstream didn’t impede the flow. Besides the malt mill a grinding mill near Efferen had a special use. Before grinding it processed oak bark for tanners. Today only street names remember these mills.
The lords and landowners along the Duffesbach used its water. They filled their moats and ponds. They could only do so on Sundays. This was when the water wasn’t needed for Cologne’s industries. These industries are reflected in the street names along the Kölner Bäche.
Today the Duffesbach is largely channeled. It’s mostly hidden underground. Above ground it flows for only about 600 meters in Cologne’s Sülz district. The Duffesbach Association formed in 2012 to preserve it. It’s a collaboration between the city of Hürth and industrial companies. These include YNCORIS RWE Power and the Cologne Ports and Goods Traffic AG. Their predecessors were the Duffesbach cleaning and drainage cooperative and the Duffesbach cooperative. The Duffesbach may be hidden but its legacy endures. It’s a testament to the city’s industrious past. The Duffesbach’s story is a reminder of Cologne’s ingenuity. It shows how humans have shaped the landscape for centuries.