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AQUEDUCTS, WATER SUPPLY AND CITY LIFE IN THE GREEK AND ROMAN WORLDS Dr P.-L. Viollet1 Abstract: The classical Greco-Roman Antiquity used for water supply both the heritage of the older civilizations of Antiquity, as well as new water technologies which appeared between the IIIrd and the Ist century BC. Water had a high value, and the urban way of life was characterized by abundance of water, for public service, pleasure, and industry, with aqueducts, water distribution systems, baths, and water-mills. Keywords: water management, aqueduct, fountain, water distribution, bath, water-mill. INTRODUCTION The Greco-roman world is often called “classical Antiquity” and it is the best known period of Antiquity. It followed many centuries of older civilizations and previous urban development which took place during the Bronze Age and to some extent inherited water technologies from this age. The first section of the paper is a short analysis of this heritage, and of the development of water technologies in Antiquity. The second section is related to water distribution in Roman cities, with a focus upon Rome, Pompeii (Italy), Nimes (France), and Petra (Jordan), a contrasting example. The third section is related to water use and management inside cities in classical Antiquity. HERITAGE IN WATER MANAGEMENT : FROM THE BRONZE AGE TO CLASSICAL ANTIQUITY During the Bronze Age, between the 4th millennium to 1150 BC, in the large interconnected area situated between the Indus, the Nile and the Aegean Sea, water management technologies developed up to a considerable extent, mostly for the needs of agriculture, with drainage and irrigation works using gravity-driven open channels (Viollet, 2010). Cities developed, in Mesopotamia, in Egypt, in the Indus valley (Harappean civilization), in Syria, in Crete (Minoan civilization) and on the Greek mainland (Mycenaean civilization). The sources of water for these early cities were (see table 1) : the large rivers or open channels derived from it (Nile, Euphrates, Tigris, Orontes...), natural springs, wells, and structures allowing to collect rainwater and to store it into cisterns. From the open channels, wells and cisterns, water was not distributed, but carried by men or by women. Urban drainage conduits existed in many of these cities. The aqueduct, defined as a manufactured long-distance conduit or channel designed as to provide a city with water, for water distribution inside the city, appeared only in the latest period of the Bronze Age, in Crete, and later in continental Greece. The sophisticated water management in the palace of Cnossos (Minoan Crete), with an aqueduct probably made with terracotta elements, baths, rainfall drainage and collection, sewage conduits, may appear as the predecessor of the model of the use of water in the GrecoRoman cities. 1 Société Hydrotechnique de France. 1 Table1. The sources of water in some Cities of the Bronze Age (3000-1150 BC). Origine of the water A short navigable canal connected to a large river Canals allowing to direct floodwater into reservoirs Gutters and cisterns for rainwater collection and storage Underground cistern fed from a spring or from groundwater infiltration , with stairs allowing to reach the water Wells Aqueduct or canal from a source in altitude Cities Uruk, Ur, Mari, Babylon (Mesopotamia), Memphis (Egypt) Jawa, Khirbet el Umbashi (Jordan, Syria) Mari (Syria), Cnossos (Minoan Crete) Mycenae, Athens, Tiryns (Mycenaean Greece), Zakros (Minoan Crete) Ugarit (Syria), Mohenjo Daro (Harapean Indus) Cnossos*, Mallia* (Minoan Crete), Pylos, Thebes (Mycenaean Greece), DurUntash (Elam) * = probable The Bronze Age civilizations came to an abrupt end by 1150 BC, under a series of troubles which caused destruction of most cities of the eastern Mediterranean area (only Egypt escaped). During the “dark age” which followed, writing was forgotten in Greece, until the VIIIth century BC when the Greek alphabet appeared, derived from the Phoenician one, and that the classical Greek civilization started. But the technologies of the great civilizations of the Bronze Age, including dam construction, open channel flows design and construction, terracotta pipes, remained. Those technologies were used in the classical Greek civilization for aqueducts construction, urban drainage : Greek aqueducts were mostly made with terracotta pipe elements ; they were generally buried and followed the slope of the land. Water distribution inside the cities of this period is poorly documented. The classical Greek period ends under the huge shadow of Alexander the Great who, in the IVth century BC, conquered the eastern world between the Aegean Sea and the Indus River, built Alexandria in Egypt, as well as many other cities. The eastern world and the western one were set into contacts, and Alexandria became a key place for science and new technologies including water technologies : pressure pipes, water-lifting machines (Archimedes’ screw, Ctesibios pump, and bucket-chain). The water-mill (with vertical wheel) appeared somewhere in the east during the Ist century BC. A key early example of an aqueduct using a pressure pipe is the first aqueduct of Pergamon (Turkey), built in the IInd century BC, which used an 3 km long siphon with a pressure-pipe made of lead. Then the Romans came, who inherited from Etruscan, Greek and Oriental civilizations and developed the most outstanding aqueduct and water supply technologies, together with a real water abundance. Water was now up to a large extent brought into the cities with aqueducts, and distributed. WATER SUPPLY AND DISTRIBUTION IN THE GRECO-ROMAN WORLD A new model for city development Cities of the classical Greco-roman Antiquity did not develop from a River as a source of water, as it was the case in the Bronze Age cities of Egypt or Mesopotamia, but rather were natural springs were available. The pure water from the spring has a high cultural value, often in a religious manner, as local cults of nymphs are often related to the sources. When those cities grow and when the available natural sources are not sufficient any longer due to the growth of the population, then new sources are brought to the cities with aqueducts. This scheme is quite evident in Rome, in Antioch (Syria), or in Nimes (Nemausus, France) for 2 example. And when a new city is created, aqueducts construction goes together with the building of the new town : this was the case in Lyon (Lugdunum, France), or in Carthage (Cartago, Africa) after this city has been re-founded by Emperor Augustus. Monumental fountains (see fig. 1), called nymphaea, are built either at the location of the original sources in the city, or at the source of the aqueduct providing the city with water, or inside the city in places where it can be fed in water by an aqueduct. Fig 1. Two examples of monumental fountains. Left : the Peirene Fountain in Corinth (Greece). Right : the Nymphaeum of Jerash (Gerasa , Jordan). Roman aqueducts and their termination points inside the city. The Roman aqueducts are masterpieces of civil engineering, many remains are still visible in Europe, in Africa, and in the Middle East. Table 2 gives a few key examples. Table 2.Characteristics of a few keynote Roman aqueducts Country City (roman name) / aqueduct Length (km) Italy Italy France France France Germany Turkey Tunisia Rome / Aqua Marcia Rome / Anio Novus Lyon (Lugdunum) / aq. of the Gier Lyon (Lugdunum) / Brevenne aq. Nimes (Nemausus) Köln (colonia Agrippina) Pergamon (Pergamum) / Kaikos aq. Carthage (Cartago) / Zaghouan aq. 91 87 86 70 50 95 50 118 Assumed flow rate (m3/day) 187000 189000 15000 10000 28000 27000 20000 17000 Within a city, water has to be distributed. A few is known from written sources and from excavations in Roman cities. The aqueduct arrives in a reservoir (castellum aquae) which is (with some exceptions) not intended to store water, but rather to distribute it within the different circuits. According to the Roman architect Vitruvius, such a castellum should allow to feed with the highest priority the public fountains, then the public monuments (baths, gymnasiums), then the private people ; so that in case of drought the public fountains would always be fed. Only few such Roman castellum have been preserved. The castellum found in Pompeii (fig.5), distributing water into 3 systems, might fit well with Vitruvius’ description, although this correspondence is not proven. The castellum found in Nimes (fig.6) distributed water to 10 circuits. From the excavations, it comes that the Roman distribution systems included secondary distribution reservoirs, and used pipes made of lead (in Italy and southern Europe), as well as wood (in northern Europe) or terracotta (in countries with earlier Greek influence). 3 The city of Rome Rome developed by the VIth century BC from small villages close to the Tiber River, in a place which was fed by natural sources. At the beginning, the first hydraulic engineering in Rome was the construction of the cloaca maxima, as a drainage system (fig 2). It was covered at the end of the VIth century, as its presence as an open channel was an obstacle to the development of the City. It is only in 312 BC that it became necessary to build a first aqueduct, the aqua Appia. New aqueducts were built following the increase of the population of the city, reaching at the end of the development a number of 11 aqueducts (fig. 3), with a total discharge estimated to about 1 million m3 (1 m3 / day / person !) N all l rina Qui Tib l na mi Vi q. er n A ia rv e S w An io a ac clo P al wall im a in Esquil ma x Ca pi tol e tus Ve atin ia pp A ve nt in Caelius A ua q A a rci Aq. Ma ll Janicule wa Fig. 2. The city of Rome under the Republic : the cloaca maxima, which was primarily a drainage canal allowing to drain the forum, was covered in the VIth century BC, and since that time has been serving as a sewer. The figure shows also the first aqueducts which were built in order to provide water to the growing city : aqua Appia (312 BC), aqua Anio Vetus (272 BC), aqua Marcia (144 BC). The Aqua Appia passes underneath mount Aventin, while the Aqua Marcia, which has a higher elevation, arrives at Mont Aventin through a siphon issuing from the Caelius. (Reproduced from Viollet, 2007) brooks Ancient swamp Elevation > 20m 1 km aqueducts The story of the first 9 aqueducts is well known thanks to the book written by Sextus Julius Frontinus, who was nominated by Emperor Nerva as curator aquarum (director for water) in 97 AC. According to Frontinus, there were in the City of Rome at his time 247 distribution reservoirs, 39 monumental fountains, and 591 public fountains with basins. We also learn from his book that : - Following Frontinus’ directorate, most public fountain could be fed by at least 2 aqueducts, keeping the continuity of the water service during maintenance works on one aqueduct. - The quality of water was very important : the two aqueducts derived from the Anio river delivered less limpid water, and that was taken into consideration regarding the use of water (pure water was preferably delivered to fountains); aqua Marcia was considered as delivering the best water ; the 11th aqueduct, aqua Alsietina (see next section) was not supposed to be distributed to public fountains because of its poor quality. - Authorization to deliver water to monuments or to some specific private houses was a privilege granted by the Emperor. - Water-men often used to deliver water to private users in a fraudulous way according to a parallel market. 4 Population (millions) Water supply (millions m3/day) Appia Julia Virgo Tepula Marcia 0,4 Anio Vetus 0,8 Alexandrina Trajana population 1,2 Claudia Anio Novus 1,6 0,8 0,4 0 300 0 -400 -300 -200 1,2 -100 0 BC Years 100 200 AC Fig.3. The increase of the water supply and of the population in Rome (from Viollet, 2007) Fig 4. Water distribution in Pompeii, with a photo of a street fountain and its distribution tower. Pompeii Pompeii, which was destroyed in 79 AC by an eruption of the volcano Vesuvius, shows a good example of a Roman distribution system (fig 4). The castellum (fig. 5) was situated at Porta Vesuvio, at the highest point of the city, and there were downstream secondary distribution reservoirs and distribution towers. Those distribution towers were fitted with a small reservoir, at the top the the tower, whose level made it possible to adjust the downstream pressure at a constant level, and not to have too much pressure in the public fountains (photo on fig. 4). The population in Pompeii was about 8000, and the daily water supply provided by the aqueduct was about 6500 m3. The ordinary people used to go to the 5 public fountains to take their water, while water was distributed to public or private baths, and to some rich houses which had their own private fountain (Jansen, 2000). Fig. 5. The castellum of Pompeii : left : outside view with the 3 exit orifices for water distribution ; right : inside view showing how the flow was separated into 3 branches. Nimes (Nemausus) Nimes is another interesting example of a Roman distribution system (Veyrac, 2006). The city was created in the VIth century BC, before Roman times, around a historical spring called “The Fountain”, a perennial but not regular source of water (average flow 100 l/s, lower flow in dry season). It was later nicely built as a nymphaeum in the Roman time. An aqueduct was built by the middle of the Ist century AC, under Claudius. Its castellum (fig. 6) was built at the altitude of 59 m, higher than the Fountain (51 m), allowing to provide water to a larger area of the city. The number of inhabitants in the Roman period is estimated to 20 000. The flow delivered by the aqueduct was probably about 28 000 m3/day. Either from the Fountain or from the aqueduct, water was distributed through lead pipes to public or private fountains, to baths (9 can be identified, there may have been more), to latrines. There were also some wells in the city, as well as an important sewer system. 500 m Th Spring Aqueduct Castellum Baths Fountains & basins Castellum The Fountain Th Th Th Th Th Th Th Th Fig. 6. Water in Nimes, with a photo of the castellum. Amphitheatre Th 100 m 80 m 60 m 6 Petra A contrasting example is Petra (Jordan), which was the old capital of the Nabatean kingdom, then, after 106 AC, became the capital of the Roman province of Arabia. There were in Petra advanced systems of rainwater collection (fig. 7) and conservation into cisterns, an heritage of older Oriental technologies. In addition to this extended system, 6 aqueducts were built in order to carry water from distant springs to downtown. As the city was built inside a set of narrow valleys, it has been also necessary to build a number of dams protecting the city from flash floods. Fig 7. A small canal for rainwater collection, above the monument so called the soldier’s tom, in wadi Farasa in Petra. WATER INSIDE THE CITIES OF THE CLASSICAL ANTIQUITY Water : a source of pleasure. Water is of high cultural value in the Greco-roman world, as we have seen from the monuments and local cults associated to it. A specific source of pleasure associated with water are the baths, which existed in the Greek world but developed up to a considerable extent from the beginning of the Roman imperial period (Manderscheid, 2000). The architecture of Roman baths became also more sophisticated. There is no doubt that the development of aqueducts made the development of public baths possible, and that the societal demand for baths probably contributed to justify the need of new aqueducts. But aqueducts were not the sole source of water for baths : wells, cisterns, springs have also been identified as sources of water to some Greek or Roman baths. In Cosa (Italy), water for the public baths was lifted using a bucket-chain system. A specific use of water as a pleasure was the nautical games (naumachia). In Rome, Emperor Augustus made constructed a specific area for such games, on the right bank of the Tiber, and an aqueduct (aqua Alsietina) was specially built in order to provide water for this area. Water : a source for industry Water is also used by industrial activities. A special interest is to be paid to water-mills. The (vertical wheel) water-mill appeared in the Ist century BC, and developed rapidly inside the Roman Empire, becoming a widely-used technology from the Ist century AC (Viollet, 2005). The Roman water-mills often used aqueducts as the source of water. Many mills were in private villas in the countryside, close to the source of grain. One astounding water-mill with 16 wheels was built in Barbegal (close to Arles, France), using a branch of the aqueduct providing Arles (Arelate) with water. But there were also many water-mills inside the cities : in Rome, there was in the IIIrd century AC a water-mill in the basement of the Caracalla baths, and there were water-mills on the Janiculus hill, on the right bank of the Tiber, using water from the aqueduct aqua Trajana, and possibly also from Aqua Alsietina. The development of water-mills inside Rome is probably associated with the fact that, from the IIIrd century, flour and no longer grain, was distributed to the population of Rome. Then grinding grain became 7 under public responsibility. Water-mills existed also in the Vth century AC on the Roman agora of Athens (fig. 8). Water management inside the cities The abundance of water created in many cities was also used the clean the sewer systems, and to improve hygiene with public latrines fed with water (fig. 9). The large monuments like amphitheatres were equipped with well-designed water-drainage systems. Also, as stated above, many cities in the Mediterranean area were equipped with advanced systems for rainwater collection and storage in cisterns (fig. 10). Fig 8. Remains of a water-mill on the Roman agora of Athens. Fig. 9. Public toilets in Corinth (Greece) Fig 10. A cistern fed from rainwater in the Nabatean city of Auara, founded in the Ist century BC by Nabatean king Aretas III (Humeyna, Jordanie). This city in the desert used to be an important centre on the road from Petra to the Red Sea. All photographs in the present paper are from the author. REFERENCES Frontinus, De Aquaeductu Urbis Romae, Latin text with translation into French with comments by P. Grimal, Les Belles Lettres (1961) Jansen, G. 2000 “Urban water transport and distribution”, in Handbook of Ancient Water Technology, O. Wikander ed., Brill, p. 103-125 Manderscheid, H. 2000 “The water management of Greek and Roman baths”, in Handbook of Ancient Water Technology, O. Wikander ed., Brill, p. 467-535 Veyrac, A., 2006, Nîmes romaine et l’eau, CNRS éditions, Paris Viollet, P.-L., 2005, Histoire de l’énergie hydraulique, Presses des Ponts et Chaussées, Paris Viollet, P.-L., 2007, Water engineering in ancient civilizations, translated by F. Holly, IAHR, Madrid Viollet, P.-L., 2010, “Water Engineering and Management in the Early Bronze Age civilizations”, in Water Engineering and Management through time – learning from history, E. Cabrera & F. Arregui ed., CRC Press/Balkema, p. 27-54 8