What are the parts of Karez?

Karez is a special underground water diversion project, which was invented by Uighurs and other nationalities in China. According to research, Karez appeared more than 20 years ago. It was called "well canal" in ancient times, which has been recorded in Chinese historical books.

Karez is an underground water diversion project that people in arid areas skillfully use the slope of the terrain for manual excavation. Each karez consists of four parts: shaft, underground culvert, surface channel and flood prevention dam. The shaft is not for water, but mainly for ventilation, taking soil during excavation and serving as an access point for maintenance. The deepest vertical well can be as deep as 100 m. Underground culvert is a water conveyance channel, and its main function is to intercept groundwater and lead it out of the ground. Groundwater flowing into culverts can also prevent excessive evaporation caused by climate drought. The function of surface channel is to lead water from the outlet of underground culvert to waterlogged dam. Laoba is a small reservoir, its function is to accumulate incoming water and adjust irrigation quantity. Around the waterlogged dam, because it attracts water, trees can be planted and farmland can be reclaimed, and it has become a vibrant oasis.

The excavation of Karez is required by specific geographical conditions. For example, the Turpan basin is surrounded by mountains, and there is little precipitation in the basin, but a lot of ice and snow have accumulated on the surrounding mountains. Every summer, when the ice and snow melt, the water will flow down the hillside, and the gravel layer on the edge of the basin will drill into the ground and become underground diving. Turpan people used the method of digging karez to intercept the underground undercurrent and use the ground for irrigation, thus making Huozhou, which is famous for its drought, open up a paradise with fragrant melons and fruits.