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
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Section of the Aqua Marcia, Tepula, and Iulia, near the Porta San Lorenzo
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sources. Under the Republic the construction and repair of aqueducts devolved upon
the censors, and their management upon the aediles, but from the time of Augustus, upon a
special
curator aquarum, assisted by a large staff of pipemasters,
fountainmasters, inspectors (
aquarii), and others, taken partly from the
number of the public slaves. The amount of water brought into Rome by its numerous aqueducts,
the first of which, the Aqua Appia, was projected B.C. 312, may be estimated from the fact
that the four still in use are quite sufficient to supply all the houses, fountains, etc., of
modern Rome.
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.
