Karez: the rivers that flow beneath the desert

Look towards the mountains from a dry village in Balochistan and a line of small pits can be seen on the ground. These pits are the mouths of wells. Beneath them runs a tunnel through which water reaches the village without any pump, electricity or fuel, only by the pull of the slope. We call it karez; in Iran it is called qanat. It is among the human inventions that made the desert fit to live in.

What is a karez

A karez is a way of reaching water underground. Its source is not a river, lake or spring but water within the earth. According to the World History Encyclopedia, it is called foggara in North Africa, falaj in Oman and the Emirates, karez in Iran and puquio in Peru.

Skilled craftsmen, known in Iran as muqannis, first identified a sloping plain of soil and gravel at the foot of a mountain where water lay below. A deep well called the "mother well" was dug there. This well was often about 100 metres deep, and the deepest recorded one reached about 300 metres. A gently sloping tunnel route was then marked out from the mother well to the village. The slope was kept such that the water kept flowing but did not damage the tunnel.

Vertical wells were dug at intervals along this route. According to a World Bank study on Balochistan, these shafts are generally 15 to 30 metres apart. Debris was removed through them, and later they served for ventilation and cleaning. A karez can be as short as one kilometre or as long as 50 kilometres.

Oldest evidence and origins

According to the World History Encyclopedia, archaeology shows that settlements of about 1,000 BCE depended on qanats. This means the system is at least 3,000 years old. It is the oldest known evidence so far.

Experts hold two views on where it began. The common view is that it was invented in ancient Persia and spread far with the expansion of the Achaemenid Empire (about 550 to 330 BCE). According to the Greek historian Polybius, Persian rulers granted the right to cultivate the land for five generations to those who brought water to barren land. The second, newer view is that it began in southern Arabia, today's Oman and the Emirates, and reached Persia from there or arose there separately.

How it spread

Experts regard the spread of the karez eastwards to Afghanistan, Pakistan, China and Japan as a result of trade links, especially the Silk Road. In the Americas it arrived with Spanish colonisers. According to the World History Encyclopedia, tens of thousands of qanats are still working in about 35 countries.

In 2016, the UNESCO World Heritage Committee, at its 40th session in Istanbul, inscribed "The Persian Qanat" on the World Heritage List. The listing includes eleven qanats in Iran. UNESCO's statement says that civilisation on Iran's desert plateau rested so deeply on these channels that it has been called the "Qanat (or Kariz) Civilisation".

Fair sharing of water

A karez is not only engineering; it is also a social system. According to UNESCO, a traditional system of communal management continues to this day alongside these qanats and makes equitable and sustainable sharing of water possible. The World Bank study says that in Balochistan too a karez is jointly owned by the community, and tribal ties carry over into shares of water.

Water flows underground, so little of it is lost to evaporation. The area watered by a karez was kept to what its flow could irrigate, so the groundwater was not exhausted.

Balochistan's karez today

A 2020 World Bank report, citing an older study, says some of the province's karez were built before 1525. The same report says that the karez enabled nomadic tribes to settle and grow fodder for their livestock, and that until a few decades ago the agricultural economy of upper Balochistan depended largely on its water.

But the system is now in trouble. According to the report, there were about 3,000 karez in the province in 1970, of which only about a third are now working. Repeated droughts since the 1960s reduced the recharge of groundwater, and farmers began installing tubewells. Since the 1970s the number of tubewells has risen from 5,000 to more than 40,000, and in some areas the water table is falling by more than five metres a year. As a result, many karez have dried up. According to a 2018 report in The Express Tribune, one area of Pishin once had 32 karez; only two remain, and one of them is about 200 years old.

Even so, according to the World Bank, the karez is still the source of drinking, household and livestock water for poor households.

This 3,000-year-old invention now stands before us as a question: can we learn to take from the earth only as much water as it can refill? The builders of the karez learned this lesson long ago.