Ali Mohtashami
Assistant Professor
UNESCO Chair on Aflaj Studies and Socio-Hydrology
Keeping Aflaj Alive
In the depths of arid and semi-arid lands, such as Oman, the falaj (plural: aflaj)—this masterpiece of engineering—guides ancient underground aquifers to the surface, as if breathing life into the desert’s body. Aflaj are more than irrigation systems; they are symbols of the sustainable interaction between humans, nature, and the environment. With minimal cost and energy consumption, they supply the water needs of villages and communities without disturbing the balance. In desert lands, where the fragility of the human–nature relationship is starkly visible, the falaj plays a vital role in preserving habitats.
The falaj is not only a network of underground channels. This historic system also includes natural structures and associated features of human settlement, such as cisterns, watermills, baths, palm gardens, and farmlands (awabi in Arabic). Together, these elements form a unique ecosystem that sustains communities, supports agricultural activities, and preserves life. For this reason, the falaj has been recognized as an inspiration for UNESCO. By focusing on the preservation of ecosystems, this approach embraces not only the falaj channels but also the natural structures and related historical components. The falaj stands as a testament to human creativity and ingenuity in harmony with nature, offering a valuable model for future generations as they face the challenges of water scarcity and environmental conservation. Therefore, the question is: how can we preserve this engineering heritage?
Below are a few effective measures in response to this question:
Protecting the Shafts’ Structure
Constructing protective embankments around the shafts of aflaj can strengthen those with unstable upper sections within riverbeds or stream channels. Building retaining walls and elevating the shaft collar above ground level (commonly applied to shafts along rivers or in areas at risk of flooding) are among the essential protective measures.
Location: Falaj Al-Khatmain, Birkat Al-Mouz
Respecting the Quantity and Quality Borders
An important legal concept relating to the aflaj system is the law of borders, in both quality and quantity. This law protects the falaj within its surrounding territory and prohibits the construction of new mother wells or any other structures within a defined distance of an existing falaj. The border prohibits individuals and companies from constructing new buildings, wells, factories, or any other infrastructure in this zone.
There are many methods for determining this border, including numerical groundwater models, empirical methods, and geographical information systems (GIS) applications.
Applying Underground Dams
An underground dam is a hydraulic structure built beneath the ground to prevent water flow. These dams serve multiple purposes: storing water for low-water seasons, controlling groundwater extraction, preventing the mixing of saline and fresh water, and rehabilitating aquifers.
The use of underground dams on aflaj can be highly beneficial. After heavy rainfall, large amounts of water flow through the falaj tunnels. Part of this water is surplus—beyond domestic and agricultural needs. This surplus can be infiltrated into the ground with the use of underground dams, helping the aquifer to recharge and recover.
Prioritizing Aflaj for Rehabilitation
Today, the aflaj irrigation system faces several challenges. One of the main issues is the deterioration of the physical infrastructure. Factors such as sedimentation and siltation, land use changes and urbanization, human activities, climate change, and the ageing of structures without proper maintenance all contribute to the decline of aflaj. These factors can ultimately cause the falaj to dry up.
Addressing this challenge requires significant investments in repairing and maintaining falaj infrastructure while preserving its cultural and historical significance. However, determining the optimal allocation of resources for rehabilitation is critical, especially under budgetary constraints. Therefore, it is necessary to prioritize aflaj in dire need of restoration and make strategic decisions based on technical factors such as flow rate, tunnel length, number of beneficiaries, and cultivated area.
