A short history of Roman aqueducts

Have you thought about where the water in your house comes from? If you live in a city, it probably comes from borewells that pump water from underground or from a water supply system that brings water from rivers, reservoirs, or lakes in the city’s outskirts through underground pipes. This water moves with the help of mechanical pumping.

Gravity effect

Way back in Roman times, water was also brought from distant rivers and springs into the city, through engineering feats called aqueducts. Unlike today’s pipes, these worked completely on gravity, without any pumping necessary. A city in the Roman Empire in the first century CE had public baths and toilets, and water fountains, while wealthy residences had their own baths and toilets. The capital city, Roma, reportedly had around 150 public toilets.

Ordinary houses got their drinking water from wells and cisterns, but this wasn’t enough to feed all the fountains, baths, and public toilets. So, Roman emperors commissioned the construction of aqueducts that could bring water from distant places, sometimes from 100 km away.

Pont du Gard
| Photo Credit:
Wikimedia Commons

Aqueducts were built over a period of 500 years, starting from around 300 BC. They are recognisable by their bridge-like structures, with a continuous series of arches on both sides enclosing the pipe carrying water. But these aerial structures are only a small part of the aqueduct; several kilometres lie underground. In an aqueduct, the water had to flow through gravity, which meant that the main water source had to be at a higher level. Then, the pipe had to have a continuous, gradual slope to allow the water to keep moving. So, whenever the aqueduct encountered a hill or elevated ground, a hole would be drilled to help it pass underground. In other parts, the aqueduct stood over ground or water like a bridge, supported by arches.

Since the water had to keep flowing, a gradual slope had to be maintained throughout. Now, Roman mathematicians didn’t have computers and calculators, and certainly couldn’t ask ChatGPT for an answer. But they had unique engineering and surveying tools to determine the slope precisely. They also ensured that the materials were solid, with no water leakage or blockages at any instance.

It was an engineering feat on a massive scale. The Roman Empire, which covered large parts of Europe, had hundreds of aqueducts. One of the most famous aqueducts is Pont du Gard, in present-day France. The capital city, Roma, alone had 11 aqueducts, and one of these is functional even today, carrying water for more than two millennia.

Hampi
| Photo Credit:
Wikimedia Commons

Did you know?

In India, one of the most well-known historical aqueducts is in Hampi, the Vijayanagara capital, which brought water from the Tungabhadra river.