One of the most distinctive sights in the Omani mountains is the falaj: the traditional system of narrow, mud-walled water channels used to irrigate fields and date plantations, and to provide villages and towns with reliable water supplies. The origins of the system go back into the mists of prehistory (the name itself perhaps derives from an old Semitic word meaning “distribution”; the true Arabic plural is aflaj, although “falajes” is often used instead). One theory holds that it was introduced by the Persians – who had developed a similar irrigation system, know as the qanat – in around the sixth century BC, although there is evidence that falaj-like irrigation systems were present in Arabia even before then.
Estimates of the total number of aflaj in Oman vary from five thousand to well over ten thousand, of which perhaps as many as four thousand are still in use. Traditionally, the reliability and size of the local falaj was the key factor underlying the size and prosperity of settlements in Oman. Nizwa, for instance, flourished thanks to its abundant water sources, including the mighty Falaj Daris. By contrast, if a falaj ceased flowing, it usually spelled the end of the village that relied on its water. Mosques can also often be seen near important sections of a falaj, offering a reliable source of water for ritual ablutions before prayers, while most of the country’s larger forts also boasted their own dedicated falaj, often flowing from an underground source directly into the building and guaranteeing a steady supply of water in the event of a siege. Aflaj remain an integral part of the traditional Omani date plantation or village – even today, many locals still use them to wash clothes in or even, in larger ones, to take a bath.
Construction and operation
The communal effort and expense involved in constructing and maintaining a falaj was a heavy burden on traditional Omani society, although it also helped foster social cohesion and a sense of shared responsibility. Locating a suitable water source using the services of a specialist water diviner was the first challenge. There are two basic types of falaj: a ghaily falaj, drawn from a water source above ground such as a river bed or mountain spring, or, more commonly, an iddi or daudi falaj, drawn from an underground well, anything up to 50m beneath the surface – many aflaj start with extensive tunnels before they emerge into the light of day. Creating such subterranean conduits was obviously a major engineering feat, as was constructing the channels themselves. In order to make sure the water keeps running, these are built on a constant, if often imperceptible, downward gradient from source to destination (although in places – such as the mountain villages of the Saiq Plateau – you’ll see channels tumbling steeply down the hillside between layers of agricultural terracing).
The operation of the typical falaj is another highly developed part of the Omani social fabric. Aflaj are collectively owned, with villagers holding shares which give them the right to a certain amount of water. Water is diverted into adjoining fields by unblocking holes in the sides of the channel for a certain amount of time (traditionally calculated by the movement of stars at night and by sundials during the day, although nowadays most people just use clocks). Large villages usually employ a full-time manager (aref) to oversee the running of the falaj, assisted by an agent, who looks after repairs and maintenance.