The Persian civilization was an incredibly rich and influent culture. It managed to attract some of the best thinkers of the time, which allowed it to grow as a nation, building important cities such as Susa or Persepolis.
A great deal of its success came from its excellent water management, both in the city and the villages, especially taking into account that a big part of its Empire spread through semi-desert or desert areas hit by droughts and high temperatures.
One of its best inventions, along with ice wells, were the qanat, a subterranean infrastructure that gathered and channeled the aquifer and valley’s rain water, transporting it into the cities and irrigated lands. Let’s see how this interesting system, today considered a UNESCO World Heritage Site, works.
A system of dwells and tunnels
The technique of the qanats was developed in Persia in the first century B.C., extending afterwards to other arid countries such as Morocco, Algeria, Libya, the Middle East and Afghanistan’s Western region.
First, a main dwell was dug in a hill, until subterranean waters were found. Then, an almost horizontal tunnel was built, from the hill up to the water source. The tunnel had a channel and a slight slope that ensured the transportation of water to the desired place. The longest the qanat, the gentlest the slope.
Apart from the main dwell, other vertical dwells would be built all along the qanat. Its aim was to ensure the water’s ventilation, management, rationing and an escape routes when the tunnel needed to be emptied. Thanks to its depth, the qanat managed to gather the water and to avoid its evaporation. Damns could also be built to hold or accumulate its flow.
Inside the qanat, there were also places accommodated for the workers to rest, water tanks and water-powered mills. As the water was passed through the earth, its flow was clean and potable, which meant it was suitable for human consumption and irrigation purposes. At the end of the qanat, a building managed the obtained water, which could also be driven towards private channels.
The Persian government was obliged to build the qanat, which transported the water from the mountains into the cities, towards the baths and public tanks. This could, then, be extended by private means.
Public tanks, known as Ab Anbar, were another wonderful engineering invention, as they included a system to capture air and cool the water, something particularly important in the dessert.
The most interesting thing of all is that this thousand-year old system is still working and allowing an equitable and sustainable distribution of water.
Source: La voz del Muro (in Spanish)