1. Roman Aqueductsand Water Supplies
3. Ancient Sources Information about aqueducts has come from:
inscriptions such as commemorations written on the aqueducts
Vitruvius in his book De Architectura
and the dryer but more technical Fontinus (AD 35-103/4) in De Aquaeductu.”
The ruins of the aqueducts themselves
4. The Predecessors of Rome In Greek times, populations usually relied on wells and springs for their water supply. Two exceptions were Samos and Pergamon.
5. The Predecessors of Rome Pergamon:
The city had at least 8 aqueducts. The Madradag Aqueduct ran in a relatively huge siphon and was four times as steep as the best known Roman siphon.
6. Wells and Cisterns In the Rome Empire wells were usually lined with masonry or terracotta rings. They collapsed easily though, and often dried up, so many of them had to be built. Furthermore, they couldn’t supply that much water, so wells would have to be built near every group of houses.
Cisterns were different. While wells tap underground water supplies, the cistern catches run-off surface water. This method was superseded by the aqueduct which brought fresh running water to the city, reducing the impluvia to a decorative function. They would continue though to be used for agricultural and industrial purposes.
In general, aqueducts were preferred over wells which were better than cisterns.
7. History of Aqueducts in Rome The first aqueduct in Rome was the Aqua Appia, built in 312 BCE, and was extraordinary engineering for its time.
Other aqueducts include the Anio Vetus built in 272-269 BCE, and the Anio Novus, built in 38-52 CE, the second started by Caligula then finished by Claudius to increase the supply brought from the Anio River.
The Aqua Virgo was completed by Marcus Agrippa in 19 BCE under Augustus’s rule. Aqueducts were an excellent form of urban renewal and were appreciated by city residents.
8. History of Aqueducts in Rome Aqua Appia
9. Aqueducts: The Source Surface water wasn’t used much. At Rome though, the Anio Vetus and Anio Novus took their water from the Anio River. Also, the Segovia aqueduct drew its water from the Rio Acebeda, the water diverted by a dam.
Cities seldom used the river water flowing by their doors. It was too polluted. Also, the water had to come from a higher source than the city in order to use gravity flow.
For the most part they turned to springs for Roman urban supplies.
10. Aqueducts: The Aqueduct Masonry conduit The typical Roman aqueduct was a surface channel, slightly below ground, surprising since our idea of an aqueduct comes mainly from the above-ground arcades.
Concrete with rough stone and brick construction was common.
The channel had to be accessible to a man for maintenance and cleaning, and that governed its size. In fact, the channel was normally only half to two-thirds full of water.
The floor and side walls were lined with waterproof cement which made the channel impervious to leaks, provided a friction-free contact surface, and made the surface continuous.
11. Aqueducts: The Aqueduct Above ground masonry conduits were very much like the underground ones, just raised on an arcade.
The incrustation of hard water on the cement in all types of conduit was a problem though. It could only be prevented by chipping it away as it formed, which became a constant duty for the waterworks staff.
12. Aqueducts: The Aqueduct Pipes could be made out of terracotta, lead, wood, and stone. In city distribution, lead pipes were the most common.
As a side note, lead pipes were not shown to lead to any lead poisoning of city inhabitants. Because the water was always flowing, it never had time to pick up a large concentration of lead.
Unlike masonry channels, pipes were meant to run full, so it ran under at least a little pressure. Because of this they needed to be laid only roughly level. This means theoretically that it was easier to lay out than a masonry channel. They were though limited to a smaller capacity because of their smaller diameter.
13. Engineering Works To cross the land, aqueducts sometimes required great works of engineering, most importantly: tunnels, low embankments, bridges, siphons, and continuous arcades
Tunnels were needed to go through ridges and other such things that it would be uneconomical to contour around. If possible, they were usually dug by sinking a number of vertical shafts and tunneling in both directions from the bottom of each. If it was to deep to build shafts, then work would begin on both sides of the tunnel and meet at the middle, like at Samos.
14. Engineering Works Bridges were used for crossing valleys or rivers and were built out of ashlar blocks until the end of the 1st century BCE, carved out of whatever stone was naturally available.
15. Engineering Works Siphons were more expensive than bridges, because their pipes had to be made strong enough to withstand high pressure. The water arrives in a traditional aqueduct to a header tank, which from there leaves by a series of lead pipes arranged side to side. At the bottom, there was a considerable pressure build up, which pushed the current back up the other side of the slope.
16. Engineering Works The engineer would build running arcades after it was no longer possible to keep the aqueduct on ground level.
17. Planning and Surveying An engineer would first decide the source site, then the castellum (the end point in the city), and then work to connect the two points using the engineering forms previously discussed.
He would use tools like the T-board and a water level to measure how level the path was, and then decide how to approach the natural contours of the ground from there.
18. Special Uses Aqueduct water was used for irrigation and industry, and probably had an importance out of all proportion to what we actually know about. They probably used different aqueducts than what was meant for the cities, as the water could be of worse quality if it wasn’t going to be used for direct consumption.
Baths also took up another amount of the overall supply. There were some baths built directly over springs, but others, especially the larger ones, required water to be channeled in. Indeed, entire aqueducts might have been built simply to service a new bath, though builders would usually use that water supply for other needs as well. The Baths of Trajan, for example, were built from 104-109 CE, linked simultaneously with the Aqua Trajana which was built in 109 CE.
19. Urban distribution A settling tank would be provided at the end of the aqueduct’s run to filter out the impurities.
Then it would reach the castellum divisorium, a small tank usually located at the edge of the city. The aqueduct enters as a single unit and leaves it as a number of separate branches, sometimes running directly to their point of use, such as for baths, but otherwise running to a number of sub-castella or water towers, where the branches are further subdivided into individual lines serving fountains and private houses, delivering a constant flow day and night.
20. The Domestic Supply Public fountain and private supplies came from the secondary castella which were equipped with a calix, a supply pipe that regulated the maximum possible consumption through an officially controlled size.
Regulation of the water supply was a full time job, and a water commission saw to it that no one took more than their allotted share.
In an excavation of Pompeii it was estimated that for a population of maybe 8,000, there were 180 people to every fountain. The fountains in Pompeii were located at about 100m intervals, and in total, the people had about 132 gallons per head. The minimum supply for the empire was probably closer to 2.5 gallons if there were aqueducts in that particular city.
21. Drains and Sewers Raised stepping stones can be seen in cities like Pompeii because the fountains often overflowed.
Domestic sewage was cleaned somewhat by the overflow of the fountains, washed away with the excess water.
Street drains and sewers were provided most simply as an open ditch. In more developed communities, these would be covered over. The discharge would all collect in a central collector sewer, which would be like the Cloaca Maxima, and would dump everything into a river at the edge of the city.
22. Drains and Sewers The largest drains were those intended for draining swampland and reclaiming it for agriculture.
An example is the Cloaca Maxima which was used to drain the swampland around the Forum area. This drain also from its earliest days around 616-578 BC used to carry out sewage. It was all purpose, combining the three jobs of: sewer, rainwater removal, and swamp drainage.
Drainage of rain and water removal depended on where it fell. If it was on a house, the water from the roof was channeled into a cistern. If on the streets and open spaces, it flowed downhill, and into a drain.
23. Bibliography Cavazzi, Franco. "Index of maps of Rome." The Roman Empire. 25 Oct. 2008 <http://www.roman-empire.net/maps/rome/>.
De Kleijn, Gerda. The Water Supply of Ancient Rome : City Area, Water and Population. City Published: J. C. Gieben Publisher, 2001.
Hodge, A. Trevor. Roman Aqueducts and Water Supply. New York: Duckworth, 2002.
Rinne, Katherine W. "Waters of the City of Rome." Waters of Rome. The University of Virginia. 25 Oct. 2008 <http://www.iath.virginia.edu/waters/first.html>.