Karez is a kind of underground water irrigation project created by the working people of all ethnic groups living in Xinjiang according to the local climate and hydro logical characteristics. There are about 1,600 Karez in Xinjiang, among which Turpan has the most and the most concentrated. According to statistics, there are 1,158 karez in Turpan, with a total length of about 5,000 kilometers, equivalent to the distance from Urumqi to Harbin. The Karez in Xinjiang is 5,400 kilometers long, equivalent to the length of the Yellow River. it can be called one of the greatest underground water conservancy projects in ancient China, which is called "underground canal" by experts in the geographical circle, and together with the Great Wall and the Beijing-Hangzhou Grand Canal, it is called the three major projects in ancient China.
Karez ancient called "well canal", Karez is also the meaning of "well hole",consists of shaft , culvert (underground channel), open channel (surface channel) and waterlogging dam (reservoir) four parts. It is the source of life for the Turpan people.
