The karez is an underground channel irrigation works common in the oases of the Western Regions. People used snowmelt and the slope of the land to link channels and shafts across the dry desert, and because the channels carry water underground, evaporation is reduced.
The practice has an old source. In the time of Emperor Wu of Han the Longshou Canal was cut by the "well-channel method", sinking shafts that joined one another so that water ran underground; the Treatise on Rivers and Canals in the Records of the Grand Historian records it, and it is regarded as one source of karez technology.
Around 1845, in the twenty-fifth year of Daoguang of the Qing, Lin Zexu described and promoted the karez at Turpan, and the karez grew on a large scale in Xinjiang.
Karez Underground Channels is the class in the chapter on Infrastructure on the karez of the Xinjiang oases, the irrigation of underground channels. People used snowmelt and the slope of the land to link channels and shafts across the dry desert, and led the water to the oasis.
