Gradients and conduits The majority of Roman aqueducts were flat-bottomed, arch-section tubes, 0.7m (2.3ft) wide and 1.5m (5ft) high internally, running 0.5 to 1 m beneath the ground surface, with inspection and access covers at regular intervals. Above-ground conduits were typically slab-topped. Flat-bottom pipes were easier to build out from town centers, where gradients could be easily controlled by digging down a few feet inside an arched opening and then lining the hole with stone or brick. Conduits under road surfaces were usually made of cut stone, while those under buildings were often made of brick.
The most famous example of a Roman aqueduct is probably the Pont du Gard in France. Built between 29 BC and 7AD, it is one of the largest surviving works of its kind in Europe. The aqueduct carries water from the Lot river 8km (5 miles) away into the city of Nîmes. It consists of three parallel channels, each about 4m (13 ft) wide and 30cm (1 foot) deep, with a total length of about 940 meters (3264 feet). There are also many smaller aqueducts in Rome itself. Some of them still carry water today.
In addition to supplying water for drinking and industry, the Romans used their aqueducts to control floods and provide irrigation for their crops. They even used some of the water to make wine and other products.
The majority of Roman aqueducts were built underground and at a modest downward inclination to enhance water flow. Siphons were used to transport water across a low basin or valley. When the aqueduct reached the other side, the siphon was broken and the water flowed freely into another channel or tank where it could be distributed through more conduits or dropped over the end wall of the tank into areas where it was needed.
Aqueducts were one of the most important inventions of the ancient world and played an essential role in making possible the growth of large cities such as Rome. An aqueduct was typically made up of several channels or pipes connected together under pressure. It was usually buried in rock crevices or trenches dug in the ground. The deeper the channel, the faster the water would flow. Channels were often separated by small vertical spaces called "jogs" to reduce the amount of time it took for water to travel from one channel to the next. These days, engineers use a similar design concept when they build pipelines for drinking water supplies.
In addition to being useful for supplying water, aqueducts provided cool, clean water that was ideal for drinking, cooking, and washing. They also helped control disease by reducing the concentration of pathogens in water sources that were likely to be contaminated with animal feces.
Aqueducts were lengthy conduits built by the Romans to transport water into towns. Many Roman aqueducts were underground. The water brought into towns was utilized for drinking water, bathing, and sewage. The majority of aqueducts were made out of stone but some were made of wood or metal.
The breadth of Rome's roads increased every year from about 250 BC until they were finally declared illegal in 194 AD. By this time they spanned more than 2000 miles. They were used for military purposes as well as travel by pedestrians and vehicles.
Rome's many bridges were also important for transportation. There were five types of bridges that were built over various waterways within the city limits: arches, semi-subterranean, suspended, half-overhead, and double bridge.
Arches were used where there was not enough space for a large opening. They resembled a small doorway with supporting posts beneath it. Arches could be used for footbridges, street bridges, and railway bridges.
Semi-subterranean bridges were built below ground level but with open-air corridors on both sides. They could be accessed by stairs or ramps. Semi-subterranean bridges were commonly used for highway bridges.