Aquae Ductus
（ὑδραγωγία, ὑδραγωγεῖον, ὑπόνομος). A water-conduit or aqueduct.
1. Greek.
As nearly all the ancient aqueducts now remaining are of Roman construction, it has been generally imagined that works of this description were entirely unknown to the Greeks. This, however, is an error, since some are mentioned by Pausanias. The Greeks, in fact, at a very early period, had some powers of hydraulic engineering, as is shown by the drainage tunnels of the lake Copa ïs, and the similar works of Phaeax at Agrigentum; and we have an instance of a channel for water being carried through a mountain to supply the city of Samos. The height of the mountain was 150 orgyiae (900 Greek feet); the length of the tunnel was seven stadia (seven eighths of a Roman mile, or about 1420 yards); its section was a square of eight Greek feet. The actual channel for the water was cut below this, and was, if the text is right, thirty Greek feet deep and three wide; the water passed through pipes from a copious spring, and was thus brought to the city (Herod.iii. 60). There are still remains of this tunnel. Müller conjectures that the work was one of those executed by Polycrates. Indeed, many of the Greek water-works appear to date from the age of the Tyrants. See Emissarium.But from early times, the Greeks, where the needs of a city called for it, constructed underground conduits following the undulations of the surface or carried through the hills by tunnels, and closely resembling the earlier Oriental aqueducts, of which they were probably imitations. Thus the conduit which supplied the acropolis of Thebes was attributed to Cadmus, and the canalization of the mountain torrents round Argos to Danaüs. The Greek aqueducts were usually rectangular channels cut in the rock or constructed of solid masonry, but in the Troad we have an instance of one composed of earthenware pipes (Hahn, Ausgrab. auf der Homer. Pergamus）
At Athens the rocky part of the city was dependent on cisterns. Two conduits entered the city on the east from the upper course of the Ilissus, which lower down was canalized, and part of its water went to supplement the Enneakrounos, below which an underground conduit ran from the river, repeatedly crossing under its bed, and accessible to use by shafts, and finally carried to the Piraeus. Below the Enneakrounos, a stream from Hymettus was carried over the Ilissus into the city. Later, two large conduits were constructed from Lycabettus on the east and west of that mountain. A system of canals from the Cephissus served to irrigate the olive-woods (E. Curtius, VII Karten von Athen). Finally, Hadrian, near the end of his reign, built an aqueduct of the Roman type, drawing its water from the Cephissus. Among the finest and best preserved of Greek aqueducts are those of Syracuse, which Thucydides (vi. 100) tells us were laid under ground to bring drinking-water into the city, and which are still in use.
2. Roman.
The Romans were in a very different position, with respect to the supply of water, from most of the Greek cities. They at first had recourse to the Tiber and to wells sunk in the city; but the water obtained from those sources was very unwholesome, and must soon have proved insufficient. Consequently, to supply the demands of the public baths and the fullers, and later of the growing population, and later still of the naumachiae, they had recourse to public works in order to bring pure water from a considerable distance—from the hills, in fact, which surround the Campagna. The date of the first aqueduct is assigned by Frontinus to the year a.u.c. 441, or B.C. 312 (De Aquaed. Urb. Rom. 4); and the number of aqueducts was gradually increased, partly at the public expense and partly by the munificence of individuals, till, in the time of Procopius, they amounted to fourteen; and, even before they were all erected, they might well excite the admiration which Pliny expresses with respect to the Claudian aqueduct (Pliny H. N. xxxvi. 123). The Roman aqueducts are among the most magnificent structures of antiquity. Some of these were constructed underground; others, latterly almost all, conveyed the water, often for long distances, in covered channels of brick or stone, over lofty arcades stretching straight through hill and valley. They started from a well-head (caput aquarum） and ended in a reservoir (castellum), out of which the water ran in Rome into three chambers, lying one above another, the lowest chamber sending it through leaden or clay pipes into the public fountains and basins, the middle one into the great bathing establishments, the uppermost into private houses. Private citizens paid a tax for the water they obtained from these public |
| Section of the Aqua Marcia, Tepula, and Iulia, near the Porta San Lorenzo |
In the time of Frontinus (A.D. 97) there were in Rome nine aqueducts, of which four were constructed in the time of the Republic and five under the Empire. These were as follows:
- 1. The Aqua Appia, begun by the censor Appius Claudius Caecus (q. v.) in B.C. 312. (See Middleton, Ancient Rome, p. 466.) Its length was 11,190 passus, of which 11,130 were carried under the earth, and the remaining sixty passus on arches, from the Porta Capena to the Porta Trigemina, where it ended. See Livy, ix. 29.
- 2. The Anio Vetus, commenced by the censor Manius Curius Dentatus in B.C. 272, the expense of its construction being defrayed out of the spoils taken from Pyrrhus. Its source was in the river Anio, above Tibur, ten Roman miles from the city; but, because of its windings, the actual length was forty-three miles, of which length only 221 passus were above ground. There are remains of this aqueduct near the Porta Maggiore.
- 3. The Aqua Marcia, built by the praetor Q. Rex Marcius in B.C. 144, at the cost of 180,000,000 sesterces. It commenced three miles south of the Via Valeria, thirty-six miles from Rome, and its length was some 61,710 passus, of which 7463 were above ground, 6935 being on arches. Vitruvius speaks of the excellence of its water as proverbial (viii. 3.1). It is still in use.
- 4. The Aqua Tepŭla, built by the censors Cn. Servilius Caepio and L. Cassius Longinus in B.C. 127. It commenced two miles to the right of the tenth mile-stone on the Via Latina. Its water was slightly warm (tepida), hence the name tepula applied to it. It was afterwards connected with the Aqua Iulia.
- 5. The Aqua Iulia, built by M. Vipsanius Agrippa (q.v.), in B.C. 33, during his aedileship. Its length was 15,426 passus, of which 7000 were above ground, partly on arches.
- 6. The Aqua Virgo, also built by Agrippa during his aedileship to supply his baths. (See Balneae.) It began near the eighth mile-stone on the Via Collatina, being in length 14,105 passus, of which 12,865 were underground. It is still in use.
- 7. The Aqua Alsietīna, or Aqua Augusta, built by Augustus. It extended from the Lacus Alsietinus, which lay 6500 passus to the right of the fourteenth mile-stone on the Via Claudia, a distance of 22,172 passus. Of this length, only 358 passus were on arches. Its water was so bad as to be used only for watering gardens and for the naumachiae.
- 8. The Aqua Claudia, begun by the emperor Caligula in A.D. 38. It began near the thirtyeighth mile-stone on the Via Sublacensis, and furnished excellent water. Its length was 46,406 passus, of which 9567 were on arches.
- 9. The Anio Novus, the longest of all the aqueducts, being nearly fifty-nine miles in length. It was begun by Caligula in A.D. 38, and finished by Claudius in A.D. 52. Of its length, 9400 feet were above ground, some of its arches being 109 feet high. (See Frontin. 15.) Near the city the Aqua Claudia and the Anio Nova united, forming two channels on the same arches.
It has been calculated that these nine aqueducts supplied the city of Rome with some 332,306,624 gallons of water a day, or about 332 gallons a head. At the present time, forty gallons per head are considered sufficient.
After the time of Frontinus two other aqueducts were built.
- 10. The Aqua Traiāna, built by Trajan about A.D. 110, and brought from the Lacus Sabatinus to supply the Regio Transtiberina.
- 11. The Aqua Alexandrīna, built by Alexander Severus in A.D. 226 from a spot between Gabii and Lake Regillus, about fourteen miles from Rome, and intended to supply the baths of Severus. There was also
- 12. The Aqua Crabra, originally carried directly through the Circus Maximus from a point near the source of the Aqua Iulia; but its water was so bad that it was abandoned to the people of the Ager Tusculanus, and hence became known as the Aqua Damnata.
See Frontinus, De Aquaeductibus Urbis Romanae; Fabretti, De Aquis et Aquaeductibus Veteris Romae; Stieglitz, Archäologie der Baukunst; Hirt, Geschichte der Baukunst; Platner and Bunsen, Beschreibung der Stadt Rom; Canina, Storia dell' Architettura Romana; Burn, Rome and the Campagna (1871); Lanciani, Topografia di Roma Antica (1880); Middleton, Ancient Rome in 1885; id. Remains of Ancient Rome (1892); and the illustration in the article Nemausus.