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— CH. 1 · THE FIRST WATER LINE —

Roman aqueduct

~3 min read · Ch. 1 of 6
6 sections

  • In 312 BC, the censor Appius Claudius Caecus commissioned Rome's first aqueduct. The Aqua Appia ran from a spring outside the city walls to the Forum Boarium cattle market. This project stood alongside the construction of the Appian Way, a military road linking Rome and Capua during the Third Samnite War. The water flowed through a buried conduit that offered protection against enemy attack. It delivered approximately 75 million liters of water daily into a fountain at the lowest point of the city. Most Romans still relied on wells or rainwater collected in jars. Public baths did not exist yet. The outlet elevation was too low to supply individual homes directly.

  • Roman engineers used specific tools to measure the land for their water channels. A chorobates served as a flatbed wooden frame about 6 meters long with water levels and plumb lines attached. Surveyors plotted horizontal courses using a groma, an apparatus later replaced by the dioptra. Vitruvius recommended a gradient of no less than 1 in 4800 to prevent erosion. The Pont du Gard in modern France descends only 17 meters over its entire length while spanning the Gardon river valley. Steeper gradients appeared in mining sites like Dolaucothi in Wales where slopes reached 1 in 700. Water flowed by gravity alone through conduits made of stone, brick, concrete, or lead. Most channels ran two-thirds full beneath the ground surface.

  • Water distribution prioritized public fountains before private users received any supply. In Frontinus's time around 103 AD, roughly 10 percent of Rome's aqueduct water fed 591 public fountains. Marcus Agrippa built or subsidized 170 public bathhouses during his tenure as aedile in 33 BC. These baths became social centers where citizens gathered daily. The free flow to basins took precedence over the small fees charged at public baths. Wealthy individuals could purchase rights to draw overflow water gratis as a state honor. Pipe stamps indicate that half of all water grants went to elite senators. Ordinary Romans without piped access drew about 67 liters per day from spouts.

  • Agricultural operations consumed vast quantities of water during the dry summer growing season. Farmers licensed to use aqueduct water irrigated fragile crops like grapes and vegetables near urban markets. At Dolaucothi in south-west Wales, miners used holding reservoirs and hushing tanks to strip earth and expose gold ore. Fire-setting weakened rock while water power drove trip-hammers to crush it further. The Barbegal complex in Roman Gaul featured 15 overshot water mills grinding flour for the Arles region. A law in the 5th century forbade unlicensed milling but enforcement remained inconsistent. Grain shortages threatened famine so authorities tolerated some illegal tapping to keep food prices low.

  • The office of curator aquarum managed Rome's water supply under Emperor Augustus. Frontinus served as consul and curator aquarum simultaneously in 97 AD under Nerva. A familia aquarum of 460 workers included slaves and free men who maintained conduits. Fines reached 10,000 sesterces for allowing tree roots to damage a channel. Polluting water within a conduit carried a penalty of 100,000 sesterces. Water rights were personal grants issued by the emperor that could not be inherited or sold with property. New owners had to negotiate fresh agreements in their own names. Despite these strict rules, corruption and theft remained common problems throughout the empire.

  • During the Gothic War in 537, Ostrogothic forces cut off aqueduct supplies to besiege Rome. Belisarius defended the city using mills stationed on the Tiber river instead. Most provincial aqueducts fell into disuse due to lack of maintenance over centuries. By the late medieval period only the Aqua Virgo provided reliable water to supplement wells. Pope Nicholas V renovated main channels of the Aqua Virgo in 1453 during the Renaissance. The standing remains inspired architects like those rebuilding Segovia in Spain. Modern engineers still study techniques used to cross valleys and maintain flow rates across vast distances.

Common questions

Who commissioned Rome's first aqueduct in 312 BC?

The censor Appius Claudius Caecus commissioned Rome's first aqueduct, known as the Aqua Appia. This project ran from a spring outside the city walls to the Forum Boarium cattle market.

What tools did Roman engineers use to measure land for water channels?

Roman engineers used a chorobates, which was a flatbed wooden frame about 6 meters long with water levels and plumb lines attached. Surveyors also plotted horizontal courses using a groma apparatus later replaced by the dioptra.

How much water did public fountains receive during Frontinus's time around 103 AD?

Roughly 10 percent of Rome's aqueduct water fed 591 public fountains during Frontinus's time around 103 AD. Water distribution prioritized these public fountains before private users received any supply.

When did Ostrogothic forces cut off aqueduct supplies to besiege Rome?

Ostrogothic forces cut off aqueduct supplies to besiege Rome during the Gothic War in 537. Belisarius defended the city using mills stationed on the Tiber river instead of relying on aqueduct water.

Who served as consul and curator aquarum simultaneously in 97 AD under Nerva?

Frontinus served as consul and curator aquarum simultaneously in 97 AD under Emperor Nerva. The office managed Rome's water supply through a familia aquarum of 460 workers including slaves and free men.

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All sources

25 references cited across the entry

  1. 1inlineSamuel Ball Platner (1929, as completed and revised by Thomas Ashby): A Topographical Dictionary of Ancient Rome. London: Oxford University. p. 29.
  2. 2bookThe Aqueducts of RomeSextus Julius Frontinus
  3. 3bookThe Aqueducts of RomeSextus Julius Frontinus
  4. 4webThe AqueductsAndré Caron
  5. 5inlineTaylor, Rabun, M., (2002), Tiber River bridges and the development of the ancient city of Rome, pp. 16–17, accessed 22 June 2013
  6. 6inlineJelena Bogdanovic, Crow, J., (team leader), Historical and Archaeological Context Constantinople and the longest Roman aqueduct Accessed August 28, 2016.
  7. 7journalMilitary Aqueducts in Roman BritainG. R. Stephens — 1985
  8. 8bookThe Aqueducts of RomeSextus Iulius Frontinus
  9. 9webRoman Aqueducts on coins
  10. 10webDe MedicinaCelsus — Loeb
  11. 11inlineVindolanda Trust website (accessed September 10, 2022)
  12. 12encyclopediaLead Poisoning and RomeJames Grout
  13. 13journalLead in ancient Rome's city watersHugo Delile et al. — 6 May 2014
  14. 14webon ArchitectureVitruvius
  15. 15bookAncient Water TechnologiesSpringer — 2010
  16. 16bookThe Aqueducts of RomeSextus Julius Frontinus
  17. 17webThe Aqueducts of RomeSextus Iulius Frontinus
  18. 18inlineDembskey, E. J., "The Aqua Claudia Interruption", Acta Classica, 52 (2009), pp. 73–82, Published By: Classical Association of South Africa, Jstor, accessed 20 March 2021, subscription required
  19. 19webThe Aqueducts of RomeSextus Iulius Frontinus
  20. 20inlineFor the earliest likely development of Roman public bathing, see Fagan, Garrett T., Bathing in Public in the Roman World, University of Michigan Press, 1999, pp. 42−44. google books preview
  21. 22journalTerminal Display Fountains ("Mostre") and the Aqueducts of Ancient RomePeter J. Aicher — Classical Association of Canada — 1993
  22. 23bookDe Re RusticaColumella — 1941
  23. 24bookA Companion to Ostrogothic ItalyJonathan Arnold et al. — Brill — 2016
  24. 25inlinePedro Tafur, Travels and Adventures (1435–1439), trans. Malcolm Letts, Harper & brothers, 1926. link to washington.edu
  25. 26bookRome in the Age of Enlightenment: the Post-Tridentine syndrome and the ancien regimeHanns Gross — Cambridge University Press — 1990