ROMAN PUBLIC WORKS

• Public Works: construction projects completed by the state for the benefit of the citizens: roads, bridges, water supply, sewers.

• Roman engineering accomplished these tasks

• Today we look at one of those public works that benefited the Roman people so much

ROMAN CONSTRUCTIONAqueducts

Aqueducts

• Aqueduct: Man-made conduit for carrying water.– Aqua=water; duct=to lead– Aqueducts bring water from its source to a distribution

point.– Most aqueducts ran underground. Bridges of stone

arches were built when a river or valley had to be crossed. This helped keep the water flow at a constant rate.

– Other peoples built structures like aqueducts: India, Persia, Egypt, Middle East.

– Romans are considered the greatest of all aqueduct builders.

Aqueducts• History:

– During the early days of Rome the water supply came from the River Tiber, wells, and springs.

– Rome needed an alternate water source for its growing population.

– Over a 500 year period (312 BC-AD226), 11 aqueducts were built to bring water to Rome from far away.

– The longest was the Anio Novus, 59 miles long.– They served a population of over 1 million in Rome!– Some are still in use.

Aqueducts

• Construction:– Only a portion of Rome’s aqueducts crossed over valleys on stone

arches. The rest consisted of underground conduits made mostly of stone and terra-cotta pipe but also of wood, leather, lead and bronze built into the mountains.

– Vertical shafts were bored at intervals to provide ventilation and access for workers.

Aqueducts

• Construction:– Except where a closed

pipe was used, the channel in which the water flowed was 3 feet wide and six feet high. This allowed workers to walk through its length for inspection and maintenance.

– Impermeable concrete was used as a waterproofing liner.

– Sedimentation tanks were used to clean impurities out of water.

Aqueducts

• Construction:– Water flowed to the city by force of gravity.– Once in the city, the water went through a series of

distribution tanks (cisterns) on high ground.– From the tanks it was distributed to all parts of the city

through lead pipes.– Water was not generally stored. The excess was used

to flush out the sewers.– Roman aqueducts were built throughout the Roman

empire. Their arches can still be seen in places like Greece, Italy, France, Spain, North Africa, Asia Minor.

Aqueducts

• Construction:– 3 Types of Aqueducts:

• Masonry conduits• Lead pipes• Earthenware pipes

– Most common in Rome were masonry conduits.

Earthenware pipe unearthed in Rome

Aqueducts

• Masonry Conduits:– The nucleus of the masonry aqueduct was the

specus or water channel.• Specus: always had stone walls, floors and roof

whether it ran underground or above.• The specus was always covered.

– Protection from sun– Protection from enemy poisoning.

Aqueducts

• Covering of channel:– Three types of covering:

• Flat slabs: very common and easily constructed. Frequently used for above ground aqueducts

• Twin Slabs: Pointed Arch: This could be used when terrain proved difficult to tunnel through and height was important.

• Half-round arch: An arch in the specus allowed the channel to be high enough for a man to enter in order to maintain the channel.

Aqueducts

• Covers:

Half Round Arch

Twin Slab

Flat Slab

Aqueducts:

• Building an Aqueduct– After water was found and the aqueduct was

commissioned to be built, the Senate assessed the cost of construction.

– They decided which spring to tap and obtained a librator (surveyor) to design a practical route.

– The librator's first task was to find a route with a relatively even gentle slope, between the source and the city. The route was then marked with wooden stakes.

Aqueducts

• Building an Aqueduct– When it was necessary to sight a straight run of

aquaduct with an existing road or path, the surveyors might use a groma to determine the right angles.

– The liberator then calculated the elevation of each end of the aqueduct.

– A leveling instrument, dioptra, was needed to take the measurements. This tool had a very limited sighting distance of about 40 yards and required the librator to move the tool hundreds of times over the distance of the proposed aqueduct.

Aqueducts

• Dioptra: This was used as a surveying device in ancient Rome to get the route as straight as humanly possible. History has proven it worked very effectively.

Aqueducts

• Building:– While building an aqueduct, the men would be

housed and fed in camps that were scattered along the route.

– Workers consisted of slaves, day laborers from small towns and unemployed workers from Rome. As may well be expected, slaves were found in the most grueling jobs such as tunneling and stone breaking.

– Work on the aqueduct would begin concurrently at various points along the route.

Aqueducts

• Building:– Every 20 yards shafts were dug from the surface to

the route of the aqueduct. – At every stage the librators checked the progress. – Once a channel had been roughed out, a chorobates

would be lowered into the trench to check the slope.

Aqueducts

• Building:– Arches were created by the

use of wooden supports that created the shape of the arch and were removed after construction. Use of Roman brick.

– The water channel was often lined with concrete

– Water could be diverted from an aqueduct into other channels by creating cisterns. The main flow could continue while some of the water was sent through small openings to supply baths or fountains

Roman Cistern

Aqueducts

• Building:– At the terminus of the aqueduct, a huge

cistern would hold the water until it was needed.

– aqueducts had long working histories – They were maintained, inspected, repaired

and improved.• The channels, as well as the traps, had to be

cleaned regularly for sediment deposits.

Aqueducts

• Facts:– As the wars in Italy ended it was no longer necessary for the

channels to be secret. Many were marked with milestones called cippi

– Cippi were used to locate specific points along the aqueduct making repairs practical.

– The business of aqueduct regulation became a venture. Private and commercial consumers paid for their water

– but it was common to steal water by connecting a pipe to the aqueduct.

– Pipe sizes were regulated and the pipes were stamped and

recorded to ensure no larger pipes were installed later.

Aqueducts

• Facts:– Ordinary people were

permitted to draw water from street fountains. It was of great importance that the water for these street fountains and the public baths be protected.

Roman fountain

Aqueducts

• Aqua Claudia:

Aqueducts

• Segovia Aqueduct: Spain

Aqueducts

• Aqua Appia

Aqueducts

• Aqua Alexandrina

Aqueducts

• Aqua Virgo: Buried arches in Rome.

Aqueducts

• Map: