An aqueduct is an artificial channel that is constructed to convey water from one location to another. The word is derived from the Latin "aqua", "water," and "ducere" ("to lead"). The word is also used for any
bridgethat carries water, similar to viaducts, though they carry water instead of a road or railway. Sufficiently large aqueducts may also be usable by boatsor ships. While a road bridge often carries the roadway at a more elevated level than the rest of the road, such a variation of height is not possible for an aqueduct.
Although famously associated with the Romans, aqueducts were devised much earlier in the
Near Eastand Indian subcontinent, where peoples such as the Egyptians and Harappans built sophisticated irrigation systems. Roman-style aqueducts were used as early as the 7th century BC, when the Assyrians built a limestone aqueduct 30 feet (10 m) high and 900 feet (300 m) long to carry water across a valley to their capital city, Nineveh. The full length of the aqueduct ran for 50 miles (80 km).
In the new world, when the
Azteccapital of Tenochtitlánwas discovered in the middle of the second millennium, it was watered by two aqueducts.
Aqueducts in Persia
In Persia from early times vague|Starting when? Finishing when? a system of underground aqueducts called
Qanatwere constructed, a series of well-like vertical shafts, connected by gently sloping tunnels. This technique:
* Taps into subterranean water in a manner that efficiently delivers large quantities of water to the surface without need for pumping. The water drains relying on gravity, with the destination lower than the source, which is typically an upland aquifer.
* Allows water to be transported long distances in hot dry climates without losing a large proportion of the source water to seepage and evaporation.
Aqueducts in India
Indian subcontinent was one of the earliest builders of aqueducts. More prominent evidence can be found at the sites of present day
Hampi. The massive aqueducts near river Tungabhadra supplying irrigation water were once 15 miles long [http://books.google.ca/books?id=_kc3LKI_slEC] .The elegant water ways in royal center supplied water for royal bath houses.
Roman aqueducts were built in all parts of the
Roman Empire, from Germany to Africa, and especially in the city of Rome itself, where they totaled over 260 miles (416 km). The aqueducts were important for supplying water to large cities across the empire, and they set a high standard of engineering that was not surpassed for more than a thousand years.
Much of the expertise of the Roman engineers was lost in the
Dark Ages, and in Europe the construction of aqueducts largely ceased until the High Middle Ages. An example of an extant small scale aqueduct system built in 1202 by Cistercian monks is the Spanish Real Monasterio de Nuestra Señora de Rueda, whose central heating and waste disposal system relied upon a series of aqueducts originating from a diversion of the Ebro River. Through most of the Middle Agesand even up to the 19th century, water was instead usually supplied through the digging of wells, though this could cause serious public health problems when local water supplies became contaminated. One notable exception was the New River, a man-made waterwayin England, opened in 1613 to supply Londonwith fresh drinking water over a distance of 38 miles (62 km). The development of canals provided another spur to aqueduct building.
The 19th century saw aqueduct building resume on a large scale to supply fast-growing cities and water-hungry industries. The developments of new materials (such as
cast iron) and new technologies (such as steam power) enabled significant improvements to be made. For instance, cast iron permitted the construction of larger, more highly pressurised inverted siphons, while steam- and electrically powered pumps enabled a major increase in the quantity and speed of water flow. England led the world in aqueduct construction, with notable examples being built to convey water to Birmingham, Liverpooland Manchester.In modern times the largest aqueducts of all have been built in the United Statesto supply that country's biggest cities. The Catskill Aqueductcarries water to New Yorkover a distance of 120 miles (190 km), but it is dwarfed by aqueducts in the far west of the country, most notably the Colorado River Aqueduct, which supplies the Los Angelesarea with water from the Colorado Rivernearly 250 miles (400 km) to the east, and the 444 mile (714.5 km) California Aqueductwhich runs from the Sacramento Delta to Lake Perris.
Uses of aqueducts
Another widespread use for aqueducts is to supply large cities with clean drinking water. Some of the famed Roman aqueducts still supply water to
Rometoday. In California, USA, three large aqueducts supply water over hundreds of miles to the Los Angeles area. Two are from the Owens Riverarea and a third is from the Colorado River.
In more recent times, aqueducts were used for transportation purposes to allow
canal barges to cross ravines or valleys. During the Industrial Revolutionof the 18th century, many aqueducts were constructed as part of the general boom in canal-building.
civil engineeringprojects, detailed study and analysis of open channel flowis commonly required to support flood control, irrigation systems, and large water supply systems when an aqueduct rather than a pipeline is the preferred solution. The aqueduct is a simple way to get water to other ends of a field.
In the past, aqueducts often had channels made of earth or other porous materials. Significant amounts of water are lost through such unlined aqueducts. As water gets increasingly scarce, these canals are being lined with
concrete, polymersor impermeable soil. In some cases, a new aqueduct is built alongside the old one because it cannot be shut down during construction.
Ancient Greek aqueducts
Pont du Gardin southern France
Barbegal aqueduct, France
Eifel aqueduct, Germany
Caesarea Maritima, Israel
Aqueduct of Segovia, Spain
Acueducto de los Milagros, Mérida, Spain
*Almuñécar, Spain (5 aqueducts - 4 still in use)
Valens Aqueduct, Istanbul, Turkey
Aqua Augusta, Italy
Aqua Claudiaand the Anio Novus, as part of the Porta Maggiore, Rome, Italy
Skopje, Republic of Macedonia
List of aqueducts in the Roman Empire
Wignacourt Aqueduct, Malta. This aqueduct was built in the 16th century to transport water from the old capital city of Malta, Mdinato the new capital city Valletta. Today, only part of this aqueduct is visible in the localities of Balzan, Birkirkaraand Santa Venera.
Aqueduct St-Clément, Montpellier, France - 17th century
Águas Livres Aqueduct, in Lisbon, Portugal(built 1731-1748)
Carioca Aqueductin Rio de Janeiro, Brazil(built 1744-1750)
Aqueduct of Teruel, Spain
Roquefavour aqueduct, France - built between 1842 and 1847
Winnipeg Aqueduct, Manitoba, Canada - built between 1915 and 1919
Canal de l'Aqueduc, Quebec, Canada
Päijänne Water Tunnelis 120 kilometers long underground aqueduct (continuous tunnel) connecting lake Päijänneto Greater Helsinki.
Wan Mat Saman Aqueduct, Kedah, Malaysia- built between 1900 and 1909
Mathur Aqueductin Tamilnadustate, India
* Surviving Spanish aqueducts in
** Aqueduct of Querétaro,
Mexico- built between 1726 and 1738, 1.3 km long and featuring 74 arches.
** Aqueduct of
Morelia, Michoacan, built between 1735 and 1738.
** Aqueduct of
Acámbaro, Guanajuato, built in 1528 [http://www.sectur.gob.mx/work/resources/LocalContent/7830/1/Acueducto%20de%20Acambaro.htm] .
Levadas, 1350 miles of 17th century aqueducts on the Portuguese island of Madeira.
*Espada Aqueduct, built 1735, in
San Antonio, Texas, United States.
Quabbin Aqueduct, 24.6 miles long tunnel, in Massachusetts, United States.
Chicopee Valley Aqueduct, 13.1 miles long, in Massachusetts, United States.
Central Arizona Project Aqueduct
California Aqueduct, a 444 miles (approx. 714.5 kilometers) long combination of canals, pipelines and tunnels, United States.
Delaware Aqueduct, in New YorkState, United States- at 85 miles (137 km) long, the world's longest continuous underground tunnel.
* High Bridge, part of the former
Croton Aqueduct, built in 1848, is the oldest surviving bridge in New York City.
List of canal aqueducts in Great Britain"Navigable aqueducts are bridge structures which carry canals over other rivers, valleys or railways or roads. They are primarily distinguished by their size, carrying a larger cross-section of water than most water-supply aqueducts. Although Roman aqueducts were sometimes used for transport, aqueducts were not generally used until the 17th century when the problems of summit level canals had been solved and the modern canal system started to appear.
Early aqueducts such as the three on the
Canal du Midi(1683) were stone or brick arches, the longest span being 18.3m on the Cesse Aqueduct (1686). However the weight of the construction to support the trough with the clay or other lining to make it waterproof made these structures clumsy and it was not until 1796 that the first large cast ironaqueduct was built at Longdon-on-Ternby Thomas Telfordon the Shrewsbury Canal. It has a total length of 57m with 3 intermediate piers. Within 10 years he had completed the far more ambitious Pontcysyllte Aqueductover the Dee valley on the Llangollen Canalwhich has a total length of 307m. Other cast iron aqueducts followed such as the single span Stanley Ferry Aqueducton the Calder and Hebble Navigationin 1839 with its innovative 50m through arch design.
The impact of new materials can be seen in the experience of the
Canal latéral à la Loirein France. It had 2 substantial arch aqueducts on the higher stretches of the Loire, the longest being 470m completed in 1838, but a river-level crossing was used to cross the Loireto the Canal de Briarebecause the consequent obstruction to the river during flooding was considered unacceptable. This proved troublesome until the 662m long steel Briare aqueductwas built in 1896, which remained the longest aqueduct in the world until the 21st century when the Magdeburg Water Bridgein Germany took the title.
Notable navigable aqueducts
Benjamin Outram's 44ft-long single-span Holmes Aqueduct on the Derby Canalin Derbywas the world's first navigable cast ironaqueduct, narrowly predating Thomas Telford's 186ft-long Longdon-on-TernAqueduct on the Shrewsbury Canal, sometimes described as the world's first "large-scale" navigable cast iron aqueduct.
Chirk Aqueduct, Wales- built between 1796 and 1801
Pontcysyllte Aqueductcarries the Llangollen Canalover the River Dee valley in north Wales, and was designed by Thomas Telfordand opened in 1805. The same canal, which includes a tunnelled section crosses a second valley on the Chirk Aqueduct. This navigable canal also supplies water to the borough of Crewe and Nantwich.
*Union Canal in
Scotlandhas many aqueducts, including the Slateford Aqueductthat takes the canal over the Water of Leith, the Almond Aqueductover the River Almond at Rathoand the very impressive Avon Aqueductover the River Avon. This is the second longest aqueduct in the United Kingdom.
*In recent years the building of the
Lichfield Aqueductprompted the UK government to pass legislation preventing a road being built in the path of a canal being renovated without providing a tunnel or aqueduct for it to pass.
Barton Swing Aqueduct- a form of swing bridgethat carries the Bridgewater Canalacross the lower Manchester Ship Canal. A 234ft section of the aqueduct rotates through 90 degrees to allow vessels to pass along the Ship Canal.
Roelofarendsveen, Netherlands(1961) (coord|52|12|55.96|N|4|37|35.46|E): carries the Ringvaart canalover the A4 highwayand the HSL Zuidbeing constructed, which are situated on land below the level of the canal (and below sea level)
*Gouwe aqueduct, near
Gouda, Netherlands: carries the Gouwe riverover the A12 highway, which is on land below the level of the river
Ash Aqueduct(1995) carries the Basingstoke Canalover the River Blackwater and Blackwater Valley Relief Road (A331).
Magdeburg Water Bridgein Germany(2003) connects the important Mittellandkanalover the river Elbeto the Elbe-Havel canal. Nearly 1 km long, it is the longest aqueduct in Europe.
Aztecthe Aztec Empire also used aqueducts
Goldfields Water Supply Scheme
*Pipeline - some used to carry water
*List of Roman aqueduct bridges
Sanitation in Ancient Rome
Viaduct- a similar structure to carry a road or a railway
Sextus Julius Frontinus, " [http://www.uvm.edu/~rrodgers/Frontinus.html De Aquaeductu Urbis Romae] " ("On the water management of the city of Rome"), Translated by R. H. Rodgers, 2003, University of Vermont
* [http://encyclopedia.jrank.org/APO_ARN/AQUEDUCT_Lat_aqua_water_and_duc.html Aqueduct entry] from
Encyclopædia Britannica Eleventh Edition
* Chanson, H. (2002). [http://espace.library.uq.edu.au/view.php?pid=UQ:11123 Certains Aspects de la Conception hydrauliques des Aqueducs Romains. ('Some Aspect on the Hydraulic Design of Roman Aqueducts.')] Journal La Houille Blanche, No. 6/7, pp. 43-57 (ISSN 0018-6368)
* Chanson, H. (2008). [http://espace.library.uq.edu.au/view/UQ:138266"The Hydraulics of Roman Aqueducts: What do we know? Why should we learn ?"] in Proceedings of World Environmental and Water Resources Congress 2008 Ahupua'a, ASCE-EWRI Education, Research and History Symposium, Hawaii, USA, Invited Keynote lecture, 13-16 May, R.W. BADCOCK Jr and R. WALTON Eds., 16 pages (ISBN-13: 978-0-7844-0976-3)
* [http://www.waterhistory.org/histories/rome/ Imperial Rome Water Systems]
* [http://www.romanaqueducts.info/ 600 Roman aqueducts with 25 descriptions in detail]
* [http://www.britannica.com/eb/art-12265 The Roman aqueduct at Kavala (Greece) - Encyclopedia Britannica]
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