Shadoof

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Shadoof. Kom Ombo, Egypt.
Shadoof in Estonia.

A shadoof or shaduf[1] (an Arabic word, شادوف, šādūf; also anciently known by the Greek name κήλων or κηλώνειον, kēlōn or kēlōneion) is an irrigation tool. A less common English translation is swape[2] and commonly called a well pole, well sweep or simply a sweep in the United States.[3]

The shadoof was originally developed in Ancient Egypt, and appears on a Sargonid seal of c.2000 BC.[4] It is still used in many areas of Africa and Asia to draw water.

Construction

The shadoof consists of an upright frame on which is suspended a long pole or branch, at a distance of about one-fifth of its length from one end. At the long end of this pole hangs a bucket, skin bag, or bitumen-coated reed basket. The bucket can be made in many different styles, sometimes having an uneven base or a part at the top of the skin that can be untied. This allows the water to be immediately distributed rather than manually emptied. The short end carries a weight (clay, stone, or similar) which serves as the counterpoise of a lever. When correctly balanced, the counterweight will support a half-filled bucket, so some effort is used to pull an empty bucket down to the water, but only the same effort is needed to lift a full bucket.

With an almost effortless swinging and lifting motion, the waterproof vessel is used to scoop up and carry water from one body of water (typically, a river or pond) to another. At the end of each movement, the water is emptied out into runnels that convey the water along irrigation ditches in the required direction.

It is estimated that a shadoof can raise over 2,500 litres per day. Typical discharge of the well is around 2 litres per second. Maximum water depth may be up to 3 metres. When larger depth is needed, the use of a sakia or noria is usually a better option. Alternatively, handpump,[5] treadle pumps[6] or electrical deep well pumps may also be used.

References

  1. ↑ "ASABE technical paper describing alternative names". Asae.frymulti.com. Retrieved 2012-04-03. 
  2. ↑ "Definition of "Swape"". Webster's Revised Unabridged Dictionary. MICRA Inc. Retrieved 2007-04-25. 
  3. ↑ Knight, Edward Henry. Knight's American mechanical dictionary. Vol. 3. New York, Hurd and Houghton: Riverside Press, 1877. 2,468. Print.
  4. ↑ Joseph Needham (1965). Science and Civilisation in China. Cambridge University Press. ISBN 978-0-521-32728-2. 
  5. ↑ "Practical Answers - Handpumps". Practicalaction.org. Retrieved 2012-04-03. 
  6. ↑ "Treadle pump". Dev.practicalaction.org. Retrieved 2012-04-03. 

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