Why Karez appeared in Xinjiang?
Turpan Depression in Xinjiang province is the world’s lowest-altitude basin, also the hottest and driest “fire island” in China. This mysterious land gave birth to thousands of years of culture and became an important intersection on the silk road. There is a particular water irrigation facility under the land. Moisturized by its trickling water, the oasis appeared on the barren Gobi desert. Karez Well, together with the Great Wall and Beijing-Hangzhou Canal, are titled as “three ancient Chinese projects”. Karez Well is also the lifeline of Turpan green agriculture.
The origin of Karez
Since there is no definite archaeological data and documentary evidence, Chinese academic circles generally hold three views about its origin. The first perspective is represented by Mr. Wang Guowei, a famous scholar with international reputation. He holds the view that Karez Well has come out in the Han dynasty early in 2,000 years ago. And the technology comes from wells and canals in the central plains of China. He also verified in detail about the exact time, spot and route of the introduction that this technique was used in western region.
The second view that takes for the birthplace of Karez is in Ancient Persia. And the technology was introduced from Persia along the silk road.
There’s a third view saying that Karez is invented by Turpan local ancestors based on the physiographic conditions.
How did Karez originate on earth? It doesn’t really matter. What’s important is that Karez links to the silk road which connects the East and West of the world. Karez exists in Afghanistan, Pakistan, Iran and the Caspian coast. It is called Kanatz in Farsi and Karyz in Arabic.
China’s Karez Well mostly concentrates in Turpan Depression, which is directly related to the historic background, natural environment and geographic condition. Located in the northeast of Xinjiang, Turpan Depression is close to Central China, and is one of the regions that deeply influenced by Central culture. It’s a place of strategic importance, and a place for cultural exchanges between East and West. As early as the Western Han dynasty, the settlement and reclamation of Jiaohe River in Turpan had been greatly developed, which brought the peak of agricultural civilization development to Turpan area.
The annual rainfall is only 16 millimeters in Turpan basin, but the evaporation can reach more than 3,600 mm. Although it is hot and scarcely rainy, the Turpan basin has the hydrogeological conditions for the construction of Karez: First, there are deep aquifers and abundant groundwater recharge sources. Second, there are large slopes that conduce to channel drainage. With mountain and peaks standing in Turpan’s north and west, where the rain and snow are concentrated in the river gullies and carry down the river. From the western mountains to the shores of southern basin, the horizontal distance is only 60 kilometers, while the height difference is 1,400 meters, and an average height difference is about 24 meters per kilometer. People skillfully take advantage of the slope difference and create Karez, thus utilize the underground currents buried deeply and bring in continuous flowing.
Nowadays, Karez Well has become one of the most meaningful and popular tourism sites in Xinjiang, and adds a special highlight along the Silk Road Tour.