Eifel Aqueduct

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).

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.

The aqueduct provided water for the fountains, baths and private homes of Colonia Claudia Ara Agrippinensium.

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.

Other springs in the region that met Roman quality and quantity guidelines were also equipped with aqueducts to feed the main line.

Archaeological excavations show that, at the lowest level, the Roman engineers had placed a loose layer of stones.

Small cracks were sealed with wood ash, which was strewn over them the first time the aqueduct was set in operation.

In 1938, while searching for a drinking water source for Mechernich, the workers encountered the feed line for the aqueduct from this area.

If they run free and open, inspect and observe the physique of the people who dwell in the vicinity before beginning to conduct the water, and if their frames are strong, their complexions fresh, legs sound, and eyes clear, the springs deserve complete approval.

If it is a spring just dug out, its water is excellent if it can be sprinkled into a Corinthian vase or into any other sort made of good bronze without leaving a spot on it.

[1]Vitruvius insisted,[2] "Consequently we must take great care and pains in searching for springs and selecting them, keeping in view the health of mankind."

In the Middle Ages, the layer of "Eifel marble" from the aqueduct was widely reused as building material.

The archaeological remains were in good enough condition here that a partial reconstruction was built to show how the original must have looked.

The Romans occasionally suffered problems of low-quality work on large projects, as witnessed by Sextus Julius Frontinus, lead official for water resources in the city of Rome, who wrote[This quote needs a citation]: No other construction requires greater care in its building as one that is to contain water.

Therefore it is necessary to supervise all aspects of such a project with great conscientiousness—proceeding fully in accord with the rules, which everyone knows, but only few actually follow.Considering the amount of surveying, underground building, and bricklaying involved, a construction of this size could not be built all at once.

It has further been demonstrated that the surveying took place separately from the building, as is in fact the rule today in large construction projects.

The actual construction time appears to have been even longer, since this estimate leaves out the question of surveying and production of the building materials.

Using devices similar to modern levels, the Roman engineers were capable of maintaining a slope as small as 0.1 percent—one metre of fall for every kilometre of aqueduct.

There were also open pools at points where various springs ran together so that maintenance personnel could keep an eye on problem areas.

This additional construction enabled water to be delivered to the higher-lying areas of the city through pressurised pipes.

The Eifel aqueduct was destroyed by Germanic tribes in 260 during an attack on Cologne, and was never brought back into operation, even though the city continued to exist.

The entire aqueduct remained buried in the earth some 500 years, until the Carolingians began new construction in the Rhine valley.

As this area has relatively little naturally occurring stone, the aqueduct became a favoured place for obtaining building materials.

The Römerkanal-Wanderweg ("Roman canal hiking trail") runs for approximately 100 kilometres (62 mi) along the aqueduct's path from Nettersheim all the way to Cologne.

The Eifel aqueduct is a very important and valuable archaeological site, particularly for the study of Roman surveying, organizational ability, and engineering know-how.

It is also a poignant symbol for the loss of technical knowledge during the decline of civilisations that between the Middle Ages and more recent times, no better use was found for the aqueduct than as a stone quarry.