Norias of Hama are historic water-raising machines for irrigation, along the Orontes River in the city of Hama, Syria.
They are tall wooden water wheels with box-like water collection compartments embedded around their rims. As the river flows, it pushes these water collection boxes underwater, where they quickly fill up, then are driven up to the top of the wheel where they empty into an aqueduct. The aqueduct can carry the water to supply buildings, gardens and farmland.
There are strong grounds for believing that many norias were operating in Hama at least by the late 12th century CE. Specific dates are known for the two exceptionally large norias from their inscriptions: Noria al-Muhammadiya created in 1361 CE and Noria al-Ma’muriyya in 1453 CE.
In terms of height, the tallest of the norias is 21 metres (69 feet) in diameter and the smallest is 7 metres (23 feet). At least five of these norias are 17 metres (56 feet) or larger. These wheels are made from different woods for different parts. The massive axles and bearings are walnut wood, while poplar was widely used for other parts of the wheel and pine and oak have also been mentioned.
Seventeen of Hama’s original norias have been conserved. They are notable for their medieval origins, for their large number and for the enormous size of two of them – for nearly 500 years the tallest waterwheels in the world. In the 21st century, Hama’s norias no longer provide a water supply but are celebrated as an example of advanced water supply technology in medieval Muslim societies and for the striking sights and sounds which they make as they turn. In 2006 the older of the two gigantic norias, the Noria al-Muhammadiya (1361 CE), was accorded Historic Mechanical Engineering Landmark designation by the American Society of Mechanical Engineers as marking a major step forward in technology internationally.