Upkeep discovery

New research shows Roman aqueduct in Constantinople (today’s Istanbul) was carefully maintained into the 12th century.

The Romans were masters of aqueduct construction. Rome’s water management expertise produced enough running water for cities, towns, baths, and mines. We know of more than 2,000 aqueducts, many of them spanning long distances. Numerous others await discovery. The most spectacular of all were the late-Roman aqueducts that provided water to Constantinople, such as the 426km-long Aqueduct of Valens, currently being studied by Gul Sürmelihindi and her colleagues at Johannes Gutenberg University in Mainz.

Water was always a problem for Roman Constantinople. An initial 60km aqueduct brought water from springs west of the city. During the 5th century, the authorities expanded it to springs lying 120km from the capital. In the end, nearly 426km of aqueduct supplied the city, mostly vaulted masonry channels large enough for someone to walk through. There were 90 bridges and numerous tunnels, up to 5km long. Some bridges carried two water channels over some 50km, the one above the other, allowing for maintenance work to be carried out while water still flowed. Enormous labour forces, probably mainly slaves, built and maintained the aqueduct. There were constant problems with limescale that formed in the running water.

The researchers were able to study the carbonate deposits through almost all the aqueduct. They calculated that the accumulation was only for about 27 years of use. Archives in Constantinople record that the aqueduct was in use for more than 700 years, until at least the 12th century. This means that the entire aqueduct was cleaned and maintained beyond Roman times into the era of the Byzantine Empire, right up to just before it ceased to work. Unfortunately, no one will be able to study how the aqueduct worked. One of the most important bridges was blown up by treasure hunters in 2020. They thought they would find gold in the ruins.

Image: the Aqueduct of Valens, completed by the Roman Emperor Valens in the late 4th century AD.