Eifel Aqueduct

The Eifel Aqueduct was one of the longest aqueducts of the Roman Empire.

The aqueduct, constructed in AD 80, carried water some 95 kilometres (59 mi) from the hilly Eifel region of what is now Germany to the ancient city of Colonia Claudia Ara Agrippinensium (present-day Cologne). If the auxiliary spurs to additional springs are included, the length was 130 kilometres (81 mi). The construction was almost entirely below ground, and the flow of the water was produced entirely by gravity. A few bridges, including one up to 1,400 metres (0.87 mi) in length, were needed to pass over valleys. Unlike some of the other famous Roman aqueducts, the Eifel aqueduct was specifically designed to minimize the above-ground portion to protect it from damage and freezing.

Before the building of the Eifel Aqueduct, Cologne got its water from the Vorgebirge aqueduct, which had its source in the springs and streams from the Ville region to the west of the city. As the city grew, this aqueduct was no longer able to provide enough water of sufficient quality: the springs contained a small amount of silt in the summer, and sometimes even ran dry. A new aqueduct was built to bring water from the springs of the Eifel into the city.

The Eifel aqueduct was built in the northern part of the region. The construction is of concrete with stones forming an arched covering. It had a maximum capacity of approximately 20,000 cubic metres (4,400,000 imp gal) of drinking water daily. The aqueduct provided water for the fountains, baths, and private homes of Colonia Claudia Ara Agrippinensium. The aqueduct remained in use until about 260, when the city was first plundered by the German tribes. After this date, it was never brought back into operation, and the city obtained its water from the old Vorgebirge Aqueduct.

The aqueduct began at a spring in the area of Nettersheim in the Urft river valley. It then travelled along the valley to Kall, where it had to overcome the divide between the Maas and the Rhine. The Roman engineers chose this spot because they were able to overcome the divide without resorting to a tunnel or a pump. The aqueduct then ran parallel to the northern Eifel Mountains, crossing the Erft near Kreuzweingarten (in the Euskirchen district) and the Swistbach with an arched bridge. In Kottenforst, northwest of Bonn, it passed through the Vorgebirge highlands. Finally, it ran through Brühl and Hürth before arriving in Cologne. Other springs in the region that met Roman quality and quantity guidelines were also equipped with aqueducts to feed the main line.

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