Roman aqueduct 280 miles long uncovered in Turkish forest

Deep in a forest in western Turkey, British archaeologists are uncovering a massive 280-mile-long aqueduct built to serve Constantinople, the capital of Rome's Eastern Empire.

Only after two years of survey work in difficult terrain has the archaeological team from Newcastle University been able to establish the true scale of the 1,600-year-old water complex.

Constructed between AD 355 and 440, and then massively restored in the 530s, the aqueduct complex is three-and-a- half times as long as its largest rival, the 82-mile-long aqueduct which served the Roman north African city of Carthage. In western Europe the longest example – at Cologne – was just 60 miles long.

By the early fifth century, Constantinople (now Istanbul) was one of the two largest cities in the world, with a population of more than 500,000. The great aqueduct complex was capable of supplying the metropolis with 28.6 million gallons of water per day.

The entire system was a marvel of civil engineering. Using specially dug tunnels, cuttings and one-, two- and three-tier purpose-built aqueduct bridges, the Roman engineers and architects achieved an incredible average gradient of one in 16,666 (four inches per mile) for the main part of the system. More than half the 280-mile-long aqueduct twists and turns through virtually impenetrable forest. The survey team has located a dozen multi-tier aqueduct bridges between 82 and 112 feet high. The entire system has around two miles of spectacular arched bridges.

The aqueduct was of great historical importance. Without it Constantinople could never have survived as the capital of the empire – a role it performed for almost 800 years.

During the 28 years it took to build (AD355-373 and 430-440) tens of thousands of paid workers would have provided the labour, so the entire project would have cost the imperial authorities colossal sums of money.