Aflaj, singularly Falaj, are channels cut into the ground for the purpose of transporting and diverting water from one place to another. The main advantage of the falaj is that it transports water to the village by the force of gravity. Its main disadvantage is the high cost of its construction. It is believed that this technique used to take water from groundwater resources originated in Central Asia and Iran and then spread to the rest of the semi-arid regions where suitable factors are available for building aflaj, and continued to spread until it reached the Sahara desert, China and South America, while there is another belief that the aflaj originated. In Oman, and from there it spread to the rest of the world, which was referred to by the Italian mission in its study in 2005 AD
The construction of the first falaj in the world is not apparent in antiquity. There are some ancient writings about the whereabouts of water, survey methods and engineering techniques related to the exploitation of groundwater, which were mentioned by Muhammad bin Al-Hassan Al-Kharji in 1017 AH in his wonderful book known as “The Hidden Water Growth”. However, there are some falajs that were built recently, about 150 years ago, such as the falajs of Ibra and Mudareb. Most of the aflaj are found in the valleys of the Western Hajar Mountains. These mountains are characterized by their steep terrain and the scarcity of soil and natural vegetation. Therefore, we find that the surface runoff is rapid, but it does not continue for a long time. In past centuries, the aflaj were the main means through which continuous water supplies could be obtained. There are more than 3000 falaj are currently alive in the Sultanate.
The three main types of aflaj
Aflaj are divided into three main types:
Daoudi aflaj: They are long channels dug underground, several kilometers long and tens of meters deep. Water is present in these aflaj throughout the year. Among the most important of them: Falaj Al-Khatameen and Falaj Daris in Al Dakhiliyah Governorate, and these two falajs are included in the World Heritage List. The construction of such aflaj dates back to the sixth and seventeenth centuries AD, and with the passing of the years, the craft of constructing Daudi aflaj became limited or almost non-existent.
Ghailian aflaj: It derives its water from water ponds or running water at depths not exceeding 3-4 meters. The water quantities of these aflaj increase immediately after the rains, and the aflaj usually dry up when the rains stop for a long time.
Aflaj Ainiya: They are the aflaj that draw their water directly from the water springs (the spring), including hot springs. The importance of this type of aflaj varies according to the quality of its water, as it ranges between hot and cold, and between fresh, suitable for drinking, and brackish and alkaline mixed with the water of the valleys that are suitable for agriculture.
Aflaj water division
The water of the falaj is divided into units of time known as the Athar, where the average duration of time is thirty minutes. It is owned by the owners of the falaj, and the water is distributed according to a traditional system known as circulation. The period of the circulation system ranges between seven and thirty days, depending on the strength of the falaj flow, the number of beneficiaries, and the soil quality. The water is distributed to the owners of the shares in two periods, day and night, called Al-Muhaidrah, and it contains twenty-four traces. The daytime watering means distributing the water of the falaj among the beneficiaries during the hours of the day. The people of the falaj used the movement of the shadow resulting from the movement of the sun as a sundial. An area with a flat surface was chosen and a column of three meters was installed on it. The area east and west of the column was divided into 24 parts, each of which equals one trail. That is, thirty minutes, but in the current time, people have turned towards using the clock.
The time of the night time is between sunset and sunrise, and people have agreed to rely on the movement of the stars for this purpose, and the elders know all the stars that are used to determine the times for distributing the falaj water at night, as they know the time of its rising and the time of its setting, and they determine the times through that until the onset of dawn. Since there is a difference in the times of rising of the stars, the time period of the effect is affected by that, and this is one of the reasons why the people of Al-Falaj follow a system whereby the period of the effect is 30 minutes.
Al-Qa’d means selling shares of the falaj water periodically according to its circulation. Anyone who has an excess amount of water can sell it for one irrigation cycle only. This sale takes place through a public auction, where buyers and sellers meet in a specific place, then the auction begins. As for selling water shares permanently, it is not affected by periods of drought and rain, but is affected by the stability of the falaj flow. It is permissible for everyone who owns a share in Al-Falaj water to mortgage his share and the method of mortgage used is that the owner of the share sells his share for a certain amount, and the seller has the right to return the amount to the buyer within a period ranging between 10 and 20 years. The buyer benefits from that share.