Aqueduct

AQUEDUCT. A channel, covered or open, cut in the rock; a waterway built of stone and sometimes faced with smooth cement; a waterway carried on stone arches across depressions; used to convey water from reservoirs, pools, cisterns, or springs to the places where it is to be used. Aqueducts may have existed even in pre-Israelite times, and continued to be developed until the excellent work of the Nabatean period (100 b.c. to a.d. 100). The Roman period shows many fine examples. Hezekiah excavated the Siloam tunnel (conduit) to bring water into Jerusalem by a way that could not be stopped up in time of siege (2Kgs.20.20; 2Chr.32.30), and this served the purpose of an aqueduct.


AQUEDUCT. Sennacherib of Nineveh seems to have been the first to build an aqueduct. He carried a great irrigation canal across a tributary of the Atrush-Gomel, near modern Jerwan, on a ninety ft. bridge of five pointed arches over thirty ft. high. It was built of twenty-inch cubes of stone with a channel sealed by mortar. Hezekiah’s Siloam tunnel was an aqueduct which showed a similar standard of engineering. Polycrates of Samos and the 2nd cent. b.c. engineers of Hel. Pergamum also built efficient aqueducts, but of all ancient peoples the Romans produced the greatest hydraulic engineers and the finest aqueducts.

Remains of these great waterworks are to be found in all parts of the old domains of the empire. The Rom. aqueduct bridges were built on a simple pattern. On a row of tall piers of stone or brick rose a series of small round arches. Above these lay the water channel of concrete, with an arched roof above it. Where the conduit crossed a deep depression, as at Segovia, Tarragona, or Smyrna, two or three rows of arches were superimposed. The famous Pont du Gard at Nimes (ancient Nemausus) has three such arcades. These arcades or bridges were, of course, only part of the total system. They were conspicuous and have tended to survive, but tunnels and channels carried the water over most of its course. Only thirty m. of Rome’s 260 m. of aqueducts which functioned in the first cent. were thus elevated. The rest ran in low conduits or underground. Nearly all of the Aqua Appia, the first of Rome’s aqueducts, built by Appius Claudius Caecus, builder of the Appian Way, was subterranean. It was begun in 312 b.c. and carried the water of the Anio ten m. into Rome.

Estimates of the volume of water delivered by aqueduct into imperial Rome vary, but a reasonable figure would be 200,000,000 gallons a day, a generous supply for 1,000,000 inhabitants. Costs were high, as an estimate of Pliny, governor of Bithynia in a.d. 112, shows. Pliny reported to Trajan (Ep. 10.37) that the city of Nicomedia, after spending “an immense sum” on an aqueduct, had been forced to abandon the work. Pliny suggested a reasonable alternative, efficient and soundly financed. In Pal. may be seen a considerable section of aqueduct used to supply Caesarea with water, and a few traces of the aqueduct which Pilate built in Jerusalem are left. He financed the scheme from the Corban fund and clashed seriously with the Jewish authorities (Jos. War II. ix. 4).

Bibliography

L. S. De Camp, The Ancient Engineers (1963).

International Standard Bible Encyclopedia (1915)

sis’-tern:

Use of Terms

1. General

2. Wells or Cylindrical Cisterns

3. Private Cisterns

4. Public Cisterns

5. Pools and Aqueducts

6. Figurative Uses

LITERATURE

Several words are rendered by "cistern," "well," "pool," the relations of which in the King James Version and the Revised Version (British and American) are as follows:

Use of Terms:

"Cistern," bo’r (Jer 2:13, etc.), or bor (2Ki 18:31). The latter word is frequently in the King James Version translated "well." the Revised Version (British and American) in these cases changes to "cistern" in text (De 6:11; 2Ch 26:10; Ne 9:25) margin (Jer 14:3), rendered "pit" in the King James Version are changed to "cistern" the Revised Version (British and American) (the latter in the American Standard Revised Version only).



1. General:

The efforts made to supplement the natural water supply, both in agricultural and in populated areas, before as well as after the Conquest, are clearly seen in the innumerable cisterns, wells and pools which abound throughout Palestine The rainy season, upon which the various storage systems depend, commences at the end of October and ends in the beginning of May. In Jerusalem, the mean rainfall in 41 years up to 1901 was 25,81 inches, falling in a mean number of 56 days (see Glaisher, Meteorological Observations, 24). Toward the end of summer, springs and wells, where they have not actually dried up, diminish very considerably, and cisterns and open reservoirs become at times the only sources of supply. Cisterns are fed from surface and roof drainage. Except in the rare instances where springs occur, wells depend upon percolation. The’ great open reservoirs or pools are fed from surface drainage and, in some cases, by aqueducts from springs or from more distant collecting pools. In the case of private cisterns, it is the custom of the country today to close up the inlets during the early days of the rain, so as to permit of a general wash down of gathering surfaces, before admitting the water. Cisterns, belonging to the common natives, are rarely cleansed, and the inevitable scum which collects is dispersed by plunging the pitcher several times before drawing water. When the water is considered to be bad, a somewhat primitive cure is applied by dropping earth into the cistern, so as to sink all impurities with it, to the bottom. The accumulation often found in ancient cisterns probably owes some of its presence to this same habit.

2. Wells or Cylindrical Cisterns:

It is necessary to include wells under the head of cisterns, as there appears to be some confusion in the use of the two terms. Wells, so called, were more often deep cylindrical reservoirs, the lower part of which was sunk in the rock and cemented, the upper part being built with open joints, to receive the surface percolation. They were often of great depth. Job’s well at Jerusalem, which is certainly of great antiquity, is 125 ft. deep (see Palestine Exploration Fund, "Jerus," 371).


3. Private Cisterns:

Private cisterns must be distinguished from public cisterns or wells. They were smaller and were sunk in the rocks within private boundaries, each owner having his own cistern (2Ki 18:31; Pr 5:15). Ancient sites are honeycombed with these cisterns. A common type in Jerusalem seems to have been bottle-shaped in section, the extended bottom part being in the softer rock, and the narrow neck in the hard upper stratum. Many irregularly shaped cisterns occur with rock vaults supported by rock or masonry piers. Macalister tells of the discovery at Gezer of a small silt catchpit attached to a private cistern, and provided with an overflow channel leading to the cistern. It is an early instance of a now well-known method of purification. The universal use of cement rendering to the walls of the cisterns was most necessary to seal up the fissures of the rock. The "broken cisterns" (Jer 2:13) probably refer to insufficiently sealed cisterns.

4. Public Cisterns:

Besides private cisterns there were huge public rock-cut cisterns within the city walls. The great water caverns under the Temple area at Jerusalem show a most extensive system of water storage (see Recovery of Jerusalem, chapter vii). There are 37 of these described in Palestine Exploration Fund, "Jerus," 217 ff, and the greatest is an immense rock-cut cavern the roof of which is partly rock and partly stone, supported by rock piers (see Fig. 1, Palestine Exploration Fund). It is 43 ft. deep with a storage capacity of over two million gallons and there are numerous access manholes. This cistern is fed by an aqueduct from Solomon’s Pools about 10 miles distant by road, and is locally known as Bahar el Kebir, the "Great Sea." One of the most recent and one of the most interesting rock-cut reservoirs yet discovered is that at Gezer. (See Palestine Exploration Fund Statement, 1908, 96 ff.) In this example, the pool of spring water is reached by a great rock-tunnel staircase which descends 94 ft. 6 inches from the surface. The staircase diminishes in size as it descends, and at its greatest, it is 23 ft. high and 12 ft. 10 inches wide. These proportions may seem unnecessarily large, but may be accounted for by the necessity for providing light at the water level. As a matter of fact, the brink of the pool receives the light from above. The work dates back to pre-Israelite times.

5. Pools and Aqueducts:

Open pools were common in every city. They were cut out of the rock and were built and cemented at points where occasion demanded. They were often of great size. The pool outside Jerusalem known as Birket es Sultan measures 555 ft. x 220 ft. x 36 ft. deep, and the so-called Hezekiah’s Pool within the walls, is 240 ft. x 144 ft. x about 20 ft. deep. The latter probably owes its origin to the rock-cut fosse of early Jewish date. The Birket es Sultan, on the other hand, probably dates from the time of the Turkish occupation. They may, however, be taken as examples, which, if somewhat larger, are still in accord with the pool system of earlier history. Pools were usually fed by surface drainage, and in some cases by aqueducts from springs at some distance away. They seem to have been at the public service, freely accessible to both man and beast. Pools situated outside the city walls were sometimes connected by aqueducts with pools within the city, so that the water could be drawn within the walls in time of siege. The so-called Pools of Solomon, three in number (see Fig. 3), situated about 10 miles by road from Jerusalem, are of large proportions and are fed by surface water and by aqueducts from springs. The water from these pools is conveyed in a wonderfully engineered course, known as the lower-level aqueduct, which searches the winding contours of the Judean hills for a distance of about 15 miles, before reaching its destination in "the great sea" under the Temple area. This aqueduct is still in use, but its date is uncertain (see G. A. Smith, Jerusalem, 131, where the author finds reason for ascribing it to the period of Herod). The course and destination of another aqueduct known as the high-level aqueduct is less definite. These aqueducts are of varying dimensions. The low-level aqueduct at a point just before it enters the Temple area was found to measure 3 ft. high x 2 ft. 3 inches wide, partly rock-cut and partly built, and rendered in smooth-troweled cement, with well-squared stone covers (see Palestine Exploration Fund, Excavations at Jerusalem, 53 ff). There are many remains of rock-cut aqueducts throughout Palestine (see Fig. 4) which seem to indicate their use in early Hebrew times, but the lack of Old Testament references to these works is difficult to account for, unless it is argued that in some cases they date back to pre-Israelite times. The great tunnel and pool at Gezer lends a measure of support to this hypothesis. On the other hand, a plea for a Hebrew origin is also in a measure strengthened by the very slight reference in the Old Testament to such a great engineering feat as the cutting of the Siloam tunnel, which is doubtless the work of Hezekiah. The pool of Siloam was originally a simple rock-cut reservoir within the walls, and was constructed by Hezekiah (2Ch 32:30). It measures 75 ft. x 71 ft. It is the upper pool of Isa 7:3. A lower overflow pool existed immediately beyond, contained by the city wall across the Tyropoeon valley. The aqueduct which supplies the upper pool takes a tortuous course of about 1,700 ft. through the solid rock from the Virgin’s fountain, an intermittent spring on the East slope of the hill. The water reaches the pool on the Southwest of the spur of Ophel, and it was in the rock walls of this aqueduct that the famous Siloam inscription recording the completion of the work was discovered.

Herod embellished the upper pool, lining it with stone and building arches around its four sides (see Palestine Exploration Fund, Excavations at Jerusalem, 154 ff), and the pool was most likely in this condition in the time of Christ (Joh 9:6,7). There are numerous other pools, cisterns and aqueducts in and around Jerusalem, which provide abundant evidence of the continual struggle after water, made by its occupants of all times (see G. A. Smith, Jerusalem, chapter v, volume I).

See also PIT; WELL, etc.

6. Figurative Uses:

Good wives are described as cisterns (Pr 5:15 ff). "The left ventricle of the heart, which retains the blood till it be redispersed through the body, is called a cistern" (Ec 12:6). Idols, armies and material objects in which Israel trusted were "broken cisterns" (Jer 2:13, see above) "soon emptied of all the aid and comfort which they possess, and cannot fill themselves again."

LITERATURE.

G. A. Smith, Jerusalem; Palestine Exploration Fund Memoirs, Jerusalem vol; Wilson, The Recovery of Jerusalem; Macalister, Bible Sidelights; Palestine Exploration Fund Statement; Bliss and Dickie, Excavations at Jerusalem; Josephus.

Arch. C. Dickie

See also

  • Cistern