Qanat: Ancient Iran’s Engineering Miracle

Date: 07 May 2025 - 22:04

News ID: ۱۳۹۳۱۶

TEHRAN -- The Iranian Plateau inherits a civilization that has undergone urbanization for more than 10,000 years, marked by perennial struggle to cope with fluctuations in rainfall throughout history.
The Persepolis World Heritage Site is one of the rare landmarks that provides insight into the culture and beliefs of ancient Iranians, Press TV wrote.
Etched on one of the walls, the largest known inscription by King Darius the Great reads, “May the land of Iran be protected from enemies, drought, and lies.”
Water scarcity has been a permanent feature of Iranian history and a very important force in shaping the socio-political landscape of Iranian society for many centuries.
Since ancient times, Iranians have had to effectively adapt to the climatic vulnerability, developing some advanced water management systems, the most prominent of which is the underground canal or qanat.
In fact, Iran is one of the few countries with a history of storing and supplying water. Qanats were first invented by ancient Iranians about 3,000 years ago and then spread to other countries, the traces of which can be seen today in Asia, Africa, and Spain in Europe.
Beginning in the Iron Age, the Persians learned how to dig aqueducts that would bring mountain groundwater to arid plains.
Two-thirds of Iran is either desert or mountains. Deserts make up more than 300,000 square kilometers of the country.
The irrigation tunnels that collected water from different layers of earth by relying only on gravity allowed agriculture to bloom in the arid desert and one of the oldest civilizations in the world to flourish.
The typical design of a qanat is that of a series of well-like vertical shafts, which are all connected by a gently sloping tunnel. This taps into groundwater and delivers it to the surface via gravity, therefore eliminating the need for pumping.
Although the methods are simple, the construction of a qanat requires a detailed understanding of subterranean geology and a degree of engineering sophistication.
The gradient of the qanat must be carefully controlled, since too shallow a gradient yields no flow and too steep a gradient will result in excessive erosion, collapsing the qanat.
A deft understanding of the soil conditions is also essential, the lack of which leads to collapses, requiring extensive rework at best and fatality for the crew at worst.
To begin with, surveyors would have to find an elevated source of water, usually at the head of a former river valley or even in a cave lake and then cut long, sloping tunnels from the water source to where it was needed.
Based on a survey, some 37,000 out of a total of 120,000 ancient qanats are still in use throughout Iran.
The decline of these engineering marvels began in the 1960s and 1970s when former monarch Mohammad Reza Shah Pahlavi initiated a land reform. The subdivision of the large estates that relied on qanats caused an administrative tangle, and many qanats fell into disrepair.
Subsequent “modernization”, marked by excessive water pumping and dam building and the declining use of qanats, has left Iran faced with a severe hydrological drought.
Fortunately, there is reason for hope. Faced with recurring droughts of high severity and duration, the Islamic Republic is vigorously following restoring qanats and other traditional historic hydraulic structures for sustainable development.
For example, Article 35 of Iran’s development plan calls for rehabilitation, repair, and dredging of qanats at an annual rate of five percent under the country’s watershed and aquifer management policies.
Modern engineering techniques can enhance the efficiency and capacity of qanats, making them a viable solution for sustainable water supply in areas facing severe water shortage.
Experts say the restoration of qanats, in addition to preserving the valuable heritage, will improve sustainable agricultural yield and reverse migration of villagers, and boost life satisfaction among local communities.
According to official statistics, about 60,000 qanats are up for restoration, which can provide more than 7 billion cubic meters of groundwater a year to the agricultural sector.
This volume of water recovered through pumping requires using 800 megawatts of electricity which some Iranians power plants currently produce by burning mazut.
Qanats drain groundwater naturally without using any energy and environmental pollution involved in it.
They also enable water to be transported over long distances by largely eliminating the risk of evaporation which accounts for up to 16% of the storage capacity of the dam reservoirs in water-stressed regions.
The underground aquifer system also has the advantage of being fairly resistant to natural disasters, such as floods and earthquakes, as well as to man-made disasters, such as wartime destruction and water supply terrorism.
A comprehensive review of the watershed and aquifer management is not a choice, but a must for Iran’s resilience in the face of challenges and the qanat system - though not a magic bullet – is a crucial solution.
The only way forward is to change our approach, take timely action, and learn from past mistakes.