Iran is a semi-arid country where two-thirds of its area is covered with deserts. But it is surprising to know that even throughout its dry regions, farming and permanent life have been existed due to a marvelous and genius underground water system known as Qanat or Kariz. Qanat is a waterway canal dug under the ground that connects the series of water wells that originate from a headwater spring (called the mother well) and transfers water to the ground surface kilometers away. A Qanat canal has different parts including an open spout and a steep canal with a lot of water wells with different depths that transfer water and ventilate the underground air, the final spot named “Payab” where the water reaches the ground surface and is available for use, and also additional parts like watermills, water reserviors, and rest areas for the workers. The Qanats of Iran are sometimes long for kilometers and transfer water to far villages for agriculture and daily use. The Persian Qanat in Khurasan, Yazd, Kerman, and Isfahan was registered as a human heritage by UNESCO in 2016. Qanat system is considered as one of the unique inventions of humans which has helped them collect and use underground water throughout the year like a natural water spring and after thousands of years, this genius technique is one of the best examples of the locals inventions in deserts like Baadgirs and it is still used as the main basis of agriculture and animal husbandry by the people who live in barrens and deserts.
Digging a Qanat
To make these genius water systems in ancient times, experts who are called Muqanni (well driller) and were local experienced geologists explored the foothills of mountains and distinguished if a specific spot is a good supply of underground water or not according to the plants, trees, and the available water springs of the area. Then they started to dig the main well (mother well) beside the pile of trees which could be the sign of water. This well could sometimes go deep to 300 meters to reach the underground water supply. The wells on the canal route were dug by the Muqanni to provide air and light during the process of digging the canal and also for extracting the soil and rock from the water route.
The length of a Qanat which affects the amount of providing water changes according to different factors like the land slope and the depth of the main well, and in other words the steeper the ground, the shorter the length of the Qanat. And in regions with low slopes, controlling the water flow and saving water is more difficult than in steep lands.
Some of the simple tools that were used by Muqannis for the time consuming and difficult job of digging a Qanat were pickaxes for carving the rocks and soil, Mandoo lights which were used since ancient times and were lighted by the oil of Kantoo plant which didn’t go off under the ground, and also simple plummet for aligning the wells.
The History of Qanats
The technology of Qanats was most probably designed and developed by Iranians about 1000 BC years ago in the drylands of Iran and helped the people start cultivating barrens and advancing their life and homeland. The skill of making Qanats was later expanded eastward to Afghanistan and China and westward to Egypt and Morocco and still many of those old Qanats are used for transferring water in mentioned countries. The oldest and longest Qanats in the world like the Qasabeh Qanat and the and Qanat of Zarch are located in Iran. The oldest available sample of Qanat in Iran is related to 2265 years ago and the newest one is related to 755 years ago.
Qasabaeh Qanat is known to be the oldest Qanat in the world, and the pieces of pottery found around the main well of the Qanat show that it dates back to 2500 – 2700 years ago (Achaemenid Era). It is also assigned to Kay Khosrow the king of the legendary Kiani Dynasty mentioned in Shahnameh (the epic book of Iran) and his great battle. This Qanat is located in Gonabad County of Khurasan Razavi Province and is a masterpiece of water management in the world like the Shushtar Historical Hydraulic System. Qasabeh Qanat, which is a UNESCO World Heritage Site, includes two main rows and six derivative rows of wells, it originates from the main well located on the foothills of Siah Kuh Mount and finishes 23 kilometers away at Qasabeh District of Gonabad city. The main well (the mother well) is about 350 meters deep and is the deepest Qanat well in the world.
Qanat of Zarch
The UNESCO-listed Qanat of Zarch is located in Zarch County of Yazd and it is the longest Qanat in the World. This Qanat is stretched about 100 kilometers through the barrens and makes visitors wonder how this big project was managed more than a thousand years ago with simple tools. Some wells of this great Qanat are located in the Jaame Mosque of Yazd, which shows that this Qanat existed since the pre-Islamic Era when this mosque was a Zoroastrian fire temple. Starting at Zarch city and providing water for 400 hectares of farms, this Qanat has three branches, and 2115 wells and the main well is 85 meters deep and provides 25 liters of water per second.