Roman Aqueducts

The ancient Romans were famous for their engineering, and few of their achievements were as impressive as their aqueducts. These systems carried fresh water from springs and rivers in the hills to cities, sometimes over distances of more than ninety kilometers. By the third century, eleven major aqueducts supplied the city of Rome itself, providing water for public fountains, baths, and the private homes of the wealthy.

Roman aqueducts did not use pumps. Instead, they relied entirely on gravity. Engineers designed each channel so that it sloped gently downward along its whole length, often dropping only a few centimeters for every hundred meters. If the slope was too steep, the fast-flowing water could damage the channel; if it was too gentle, the water could stop moving. Achieving such precise slopes over long distances required careful measurement of the land.

Although many people picture aqueducts as tall stone bridges with rows of arches, most of each aqueduct actually ran underground, in tunnels or covered channels. This protected the water from dirt and heat and made the system harder for enemies to damage. Bridges were built only where the channel had to cross a valley. The most famous of these, the Pont du Gard in southern France, still stands today, almost two thousand years after it was built.