Aqueducts

Sennacherib’s Aqueduct

Around 691 BCE the Assyrian king Sennacherib ordered the construction of a ten-mile (16 km) long water channel. The channel fed water from eighteen different sources in the nearby mountains into Nineveh, Sennacherib’s capital city. Where the water supply had to cross a valley the Assyrians raised the water channel on five stone arches and thus created the first aqueduct.

Some nine hundred yards (823 m) long, the aqueduct was made from hardened earth and was waterproofed with molten tar. The arches were thirty feet (9 m) high in places. The canal was fed by small streams to ensure that Nineveh had enough water for its parks, palaces, and botanical gardens. Two small dams controlled the flow of fresh water.

Sennacherib’s famous aqueduct was destroyed in 612 BCE, when Nineveh was sacked by the Babylonians and the Medes. Its ruins, however, inspired the ancient Romans to build a series of aqueducts that were the envy of the world.

Roman Aqueducts

At the beginning of the fourth century CE, the city of Rome required a total of about 38 million gallons of fresh water piped in every day. To satisfy this need, between 312 BCE and 226 CE the Romans built eleven aqueducts to bring water from the surrounding hills to their city.

Most of the Roman aqueducts were built of limestone. In places where the water channels passed high above the ground, they were supported by up to three rows of arches built on top of each other. Others aqueducts consisted of underground pipes made of stone, clay, wood, and bronze.

Channels and pipes were sloped to allow water to flow freely through the aqueduct. Water was collected in special tanks called castella within the city precincts before it was channeled out to public baths and the wealthier private houses. Extra water was used to flush out the city’s sewers.

The water channels at the top of the open-air aqueducts were usually three feet (91 cm) wide and six feet (183 cm) high. This design made it possible for workers to walk along the aqueducts and deal with any cracks or blockages. A team of repairmen worked constantly under the supervision of a curator to keep the aqueducts in excellent condition. Underground pipes could be inspected through airshafts dug into the hills.

Decline and Destruction

The Romans built aqueducts all over their empire, including North Africa and in countries like France, Spain, Greece, Italy, and Malta. As the empire began to decline in the fourth century CE, many of the aqueducts fell into disrepair. In the fifth century CE, the Ostrogoth warlord Vitiges had ten of Rome’s aqueducts destroyed and thereby cut off most of the city’s water supply. He missed one, however, known as the Aqua Virgo, because it ran mostly underground. In time this aqueduct also fell to ruin as people went back to fetching water from rivers and wells.