Carnuntum's wastewater disposal and canals

Main drainage channel of the Auxiliary Fort (Photo: T. Mauerhofer)

The supply of sufficient food and clean drinking water for humans and animals, a functioning sewage system, bathing facilities and good medical care were important basic requirements in the everyday life of large Roman cities. Many Roman cities therefore also had modern-looking sewage systems in addition to a large-scale water supply network. The sewers, often built from reused building materials (so-called spolia), drained the latrines, baths and fountain overflows and ensured that roof and street water drained away quickly during rainfall. A functioning sewer system was necessary to prevent the possible spread of diseases and epidemics. In the military camps, too, the sewage system was one of the most important hygienic facilities, together with the crew toilets, the camp baths and the camp hospital, in order to keep the 6,000 or so legionnaires healthy and ready for action.

In Carnuntum, as in most Roman cities of the time, there was a canal system running under the streets. It usually had brick walls, a floor made of brick slabs and was covered with stone slabs. Wastewater and rainwater were often collected in separate channels and fed into a large stream. The large sewer collected the waste water from the smaller side sewers and let it flow into soakaways or down towards the Danube. Public toilets (latrines) were also part of the facilities in the settlements and the waste was also fed into the sewage system. Most private houses did not have their own latrine and were not connected to the municipal sewer system, so the inhabitants had cesspits at their disposal. However, there is also evidence of towns that had no sewer system at all: Flavia Solva near Leibnitz near Graz (Styria), for example, where there was no sewer system and the drinking water supply and wastewater disposal were carried out without exception via wells and soakaways.

Various sections of the sewage system have already been investigated during excavations in the settlement area of Carnuntum. At the end of the 1970s, a drinking water pipe was discovered in the western canabae north of the cavalry camp, which crossed the main sewer of the auxiliary fort. Normally, the sewer was always laid under the fresh water pipe so that the drinking water could not be contaminated by leaking liquids from the faecal sewer. Here, however, the drinking water pipe runs under a sewage pipe, which was forbidden according to Roman building regulations. It is not known why the sewer was not laid deeper. It may have been to avoid the necessary movement of material, which would have had to interfere with the unstable, gravelly subsoil. By today's standards, however, one has to speak of "botching".

Drinking water pipe in the Auxiliary Fort (Photo: T. Mauerhofer)

In 1993, a latrine and a surrounding sewer were uncovered in the area of the Auxiliary Fort. Compressed alluvial material containing plant and animal remains was found in the bend of the canal, which is why sediment samples could be taken for bioarchaeological investigations. The finds date from the end of the 2nd to the beginning of the 3rd century and show traces of barley, emmer and lentils, among other things, which indicate kitchen and hearth areas. In addition, remains of fruit such as figs, vines, apples, pears, plums and strawberries were found in a nearby latrine, as well as oil and spice plants. Animal remains were also found in the canal, such as bone remains of smaller domestic animals and vertebrate groups. The domestic animal remains examined include sheep, pigs, cats and small dogs, as well as chickens and smaller animals such as moles and green toads. Insect remains such as houseflies, humpback flies and molluscs were also found.

Skull fragment of a house mouse from the canal of the Auxiliary Fort. (Photo: Rudolf Gold, Institute of Paleontology, University of Vienna)

Further reading on this text:

G. K. Kunst – S. Radbauer, Interdisziplinäre Forschungen in der Zivilstadt von Carnuntum. Grabungs- und Aufarbeitungsprojekt Weststraße, in: M. Meyer – V. Gassner (Hrsg.), Standortbestimmung. Akten des 12. Österreichischen Archäologentages, Wiener Forschungen zur Archäologie 13 (Wien 2010) 281–295.

M. Philipp - M. Popovtschak - U. Thanheiser - G. K. Kunst - W. Waitzbauer - C. Frank, Aufgestaut - Bioarchaeologische Funde aus einem kaiserzeitlichen Kanal im Auxiliarkastell Carnuntum, in: D. Beyll - W. Hameter - C. Kandler (eds.), Carnuntiner Wege. Festschrift for Manfred Kandler on his 80th birthday, Römisches Österreich Jahrgang 44 (2021) (Graz 2021) 75-102.

A. O. Just, Die Kreuzung einer römischen Trinkwasserleitung mit dem Hauptwasserkanal des Auxiliarkastells der Provinzhauptstadt Carnuntum (Petronell-Carnuntum 2003).

H. Stiglitz, Zur Wasserversorgung der Zivilstadt von Carnuntum, in: F. Humer (ed.), Römische Thermen. Forschung und Präsentation; Akten des Internationalen Kolloquiums veranstaltet vom Archäologischen Park Carnuntum und der Gesellschaft der Freunde Carnuntums, 17 - 18 September 2009 in der Kulturfabrik Hainburg (Hainburg 2011) 101-106

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