A shadoof is a mechanical irrigation tool that was first developed in a part of western Asia called the Fertile Crescent more than 4,000 years ago. It is still used to draw water in many parts of the world that do not have ready access to electric water pumps. This tool is also known as a shaduf, dhenkli, picottah, swape or counterpoise-lift.
In many ways, a shadoof resembles a seesaw. A strong pole, often made from wood or bamboo, is suspended across an upright structure so that the fulcrum sits roughly one-fifth of the way down its length. A heavy counterweight made from rocks and debris in a bucket, basket or animal hide is suspended from the short side of the pole, and a rope and bucket are tied to the end of the long side. The leverage exerted by the length of the pole allows the operator to pull down on the rope to raise the weight and fill a bucket of water, and the counterweight brings the full bucket back up. A gentle, rhythmic swinging motion dumps the water from the bucket into an irrigation ditch or canal close to the long end of the shadoof.
A shadoof is used only for pumping surface water, because the length of its mechanical process does not permit it to lift water from a depth greater than about 10 feet (about 3 m). Although it is limited in the depth it can access, it is able to pump a remarkably large volume — as much about half a gallon (about 2 liters) per second. In India, the shadoof deficiency in pumping from depths has been circumvented by an innovation known as a picottah or dhenkli, in which several shadoofs are mounted in a series, one above the other. This enables water to be raised a considerable height by manpower with only a minimal loss in efficiency.
The invention of the shadoof is believed to have revolutionized agriculture in the ancient world by dramatically improving the efficiency of small-scale irrigation. Its importance was so great in the Fertile Crescent that the image of a shadoof was embossed on a Sargonid seal dating from 2000 B.C. Some archaeologists believe that ancient civilizations with knowledge of the shadoof, such as the Egyptians, Sumerians and Babylonians, might have used them to move the immense blocks used in the construction of their monuments. Despite the age of the technology, its cheap construction and its ability to be operated by hand has led to it being used in remote Indian and Egyptian farms even in the 21st century.