The Xinjiang Qanat System of the Turpan Oasis

What Do Scientists Know About the Turpan Karez Wells of China?

Qanat Well Head in Turfan
Qanat Well Head in Turfan. Antoine Sipos

The Xinjiang Qanat System is a remarkable feat of irrigation engineering skill, and it is considered one of the three great wonders of China, after the Han Dynasty (206 BC-220 AD) Great Wall and the Sui Dynasty (581-618 AD) Beijing-Hangzhou Grand Canal. The qanat (also known as a karez) system is a rich water source for the Turpan Oasis, tapping groundwater stored in the deep subsurface gravel layers of the Gobi belt.

What makes this all the more interesting is the fact that scholars are still not agreed upon when the qanat system was built... and that begs the question of who built it.

Qanats in the Deserts

A qanat is a system of underground tunnels and wells that tap deeply buried aquifers in arid and semi-arid places. In brief, a well is dug into the aquifer, a horizontal tunnel is excavated from the well to a surface collection place and ventilation shafts are placed at intervals along the tunnel to provide maintenance access.

Invented by the Persians in the 7th century BC, qanat technology was spread by imperialism: outside of Persia by the 6th century Achaemenid king Darius the Great; into Syria and Jordan by the Romans in the first and second century AD; into North Africa and Spain by the Islamic civilization in the 12th and 13th centuries AD; and finally into North and South America during the 16th century Spanish conquest.

The only place in China where qanats exist at all is in Xinjiang Uyghur Autonomous Region, in the Turfan basin on the far western edge of China's realm. Deserts make up 43% of Xinjiang province, oases only about 4.3% and the rest is mountains. In the 2nd century BC, the international trade network called the Silk Road was dependent on a line of strategically situated oases wedged between the Tianshan Mountains and the Taklamakan Desert in the Tarim and Turfan basins.

Turpan was an important oasis in the eastern-most segment of the Silk Road, and, even today, more than 95% of the total population, and almost all the agriculture, settlements and industries in Xinjiang, are concentrated in the Turpan Oasis.

The Size and Complexity of the Turpan Qanat System

The Turpan qanat system includes at least 1,039 qanats (some internet sources suggest as many as 1,700), with underground channels stretching for a length of more than 5,000 kilometers, or about 3,100 miles. While there is no doubt that the origins of the Turpan Oasis were natural--the oasis is fed by snow melt off the Tianshan mountains--there is also no doubt that the Xinjiang Qanat System was built to increase the available access to water. Whether the qanats were built as a result of climate change or to support a population increase or even provide year round water is open to debate: probably a little of all those things.

Estimates for the construction date of the qanats vary from the first century BC to the 19th century AD. The system is so successful that grapes are grown in a region of what is essentially a continental desert--the earliest grapes in Turpan are from the Subeixi culture Yanghai tombs, with a AMS radiocarbon date of about 300 BC.

What we know for sure is that in the 1950s, an intense increase in well irrigation was established in Turpan, over-exploiting the aquifer: since then the majority of the qanats have dried and become abandoned. Only 238 were functioning in 2009.

The Karez Wells in Turpan were inscribed into UNESCO's Tentative List of World Heritage Sites in 2012.


This article is a part of the guide to the Silk Road, the guide to the Ancient Societies of the Central Asian Steppes and the Dictionary of Archaeology.

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