Saqiyah

The sakia is a large hollow wheel, traditionally made of wood. One type has its clay pots or buckets attached directly to the periphery of the wheel, which limits the depth it can scoop water from to less than half its diameter. The modern version is normally made of galvanized sheet steel and consists of a series of scoops. The modern type dispenses the water near the hub rather than from the top, the opposite of the traditional types. It is a method of irrigation frequently met within various parts of the Indian subcontinent.

Sakia wheels range in diameter from two to five metres. Though traditionally driven by draught animals, they are now increasingly attached to an engine. While animal-driven sakias can rotate at 2–4 rpm, motorised ones can make as much as 8–15 rpm. The improved modern versions are also known as zawaffa and jhallan.

Schematics of an ideal modern sakia in a spiral design (Fathi model; drawing by FAO)

The historical Middle-Eastern device known in Arabic as saqiya usually had its buckets attached to a double chain, creating a so-called "pot garland". This allowed scooping water out of a much deeper well.

An animal-driven sakia can raise water from 10–20 metres depth, and is thus considerably more efficient than a swape or shadoof, as it is known in Arabic, which can only pump water from 3 metres.

The sāqiyah might, according to Ananda Coomaraswamy, have been invented in India, where the earliest reference to it is found in the Panchatantra (c. 3rd century BCE), where it was known as an araghaṭṭa;[3] which is a combination or the words ara (speedy or a spoked[wheel]) and ghaṭṭa "pot"[4] in Sanskrit. That device was either used like a sāqiyah, to lift water from a well while being powered by oxen or people, or it was used to irrigate fields when it was powered in the manner of a water-wheel by being placed in a stream or large irrigation channel. In the latter case we usually speak of a noria as opposed to a sāqiyah.[5]

Paddle-driven water-lifting wheels had appeared in ancient Egypt by the 4th century BCE.[6] According to John Peter Oleson, both the compartmented wheel and the hydraulic noria appeared in Egypt by the 4th century BCE, with the sakia being invented there a century later. This is supported by archeological finds at Faiyum, where the oldest archeological evidence of a water wheel has been found, in the form of a sakia dating back to the 3rd century BCE. A papyrus dating to the 2nd century BCE also found in Faiyum mentions a water wheel used for irrigation, a 2nd-century BC fresco found at Alexandria depicts a compartmented sakia, and the writings of Callixenus of Rhodes mention the use of a sakia in the Ptolemaic Kingdom during the reign of Ptolemy IV Philopator in the late 3rd century BCE.[7]

Early Mediterranean evidence of a sakia is from a tomb painting in Ptolemaic Egypt that dates to the 2nd century BCE. It shows a pair of yoked oxen driving a compartmented waterwheel. The sakia gear system is already shown fully developed to the point that "modern Egyptian devices are virtually identical".[8] It is assumed that the scientists of the Musaeum, at the time the most active Greek research center, may have been involved in its implementation.[9] An episode from Caesar's Civil War in 48 BC tells of how Caesar's enemies employed geared waterwheels to pour sea water from elevated places on the position of the trapped Romans.[10]

The term used by Talmudic sources for a sakia is 'antelayyā-wheel.[11]

Al-Jazari's advanced saqiya, both animal- and water-wheel-driven (1206).

A manuscript by Ismail al-Jazari featured an intricate device based on a saqiya, powered in part by the pull of an ox walking on the roof of an upper-level reservoir, but also by water falling onto the spoon-shaped pallets of a water wheel placed in a lower-level reservoir.[12]

Complex saqiyas consisting of more than 200 separate components were used extensively by Muslim inventors and engineers in the medieval Islamic world.[13] The mechanical flywheel, used to smooth out the delivery of power from a driving device to a driven machine and, essentially, to allow lifting water from far greater depths (up to 200 metres), was first employed by ibn Bassal (fl. 1038–1075), of al-Andalus.[14][15]

The first known use of a crankshaft in a saqiya was featured in another one of al-Jazari's machines.[16] The concept of minimising the intermittence is also first implied in one of al-Jazari's saqiya devices, which was to maximise the efficiency of the saqiya.[16] Al-Jazari also constructed a water-raising device that was run by hydropower, though the Chinese had been using hydropower for the same purpose before him. Animal-powered saqiyas and water-powered norias similar to the ones he described have been supplying water in Damascus since the 13th century,[17] and were in everyday use throughout the medieval Islamic world.[16]