Roman History


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This is some helpful information on how the aqueducts were used, and what they did.

Ancient Aqueducts

   The earliest form of aqueduct was the qanaat. A qanaat is a tunnel that begins slightly below the water table in the foothills of a mountain or a range of hills. This tunnel leads away from the foothills, gradually downhill, to carry water to a village or city. Qanaats were used widely throughout the Middle East and Northern Africa (where they were known as fogarras). Their greatest development, however, was in Persia (now Iran). There qanaats are still in use and are constructed in much the same manner as they were in ancient times.

   A famous early tunnel aqueduct was cut through solid rock in about 700 BC to carry water from the spring of Gihom to the Siloam reservoir in Jerusalem, a distance of about 1,750 feet (530 meters). In 691 BC, King Sennacherib of Assyria ordered construction of the aqueduct of Jerwan, which brought water from a tributary of the Greater Zab River to Nineveh, some 50 miles (80 kilometers) away. Another aqueduct, built on the Aegean island of Samos in about 530 BC, traveled through a hill by means of a tunnel about 3,300 feet (1,000 meters) long. Water flowed through clay pipes laid within the tunnel.

   The most famous aqueduct builders of ancient times were the Romans. The word aqueduct comes from the Latin aqua ("water") and ducere ("to lead"). Roman engineers built the main portions of their aqueducts at ground level or underground where possible. The water fed through free-flowing conduits. When it was necessary for the Roman aqueducts to cross valleys or descend to plains, they were often carried on arched bridges, or arcades. Some bridges were built with two or three tiers of arches to gain the height needed to maintain an even flow. The bridges and arcades were more difficult to build and required more maintenance than the surface level or underground portions of the aqueducts.

   Water for the city of Rome was supplied by 11 major aqueducts built over a period of more than 500 years. The first one, the Aqua Appia, was built in 312 BC and was 10 miles (16 kilometers) long. The last, the Aqua Alexandrina, was built in about AD 226. The longest was the 58-mile (93-kilometer) Aqua Marcia, built in 144 BC.

   Roman engineers built aqueducts in numerous other parts of their empire, notably France, Spain, and Northern Africa. Remains of these aqueducts still exist. A few of them, such as the one at Segovia, Spain, have remained in use. One of the most striking of the old Roman aqueducts is the Pont du Gard in southern France, which the Romans built to a height of 160 feet (49 meters) by stacking three bridges.