Dredging worker Turxun Abdul dumps a 40-kilogram-weight barrel of silt dredged from a karez well as he tries to repair a karez well in Turpan, northwest China's Xinjiang Uygur Autonomous Region, April 3, 2015. The karez wells are vertical shafts and subterranean canals that surface in the form of ditches and small ponds. The karez irrigation system, which are composed of vertical shafts, subterranean and ground canals, and small reservoirs, was built 2,000 years ago and is considered one of China's greatest surviving ancient man-made structures, along with the Great Wall and the Grand Canal. Turpan, the hottest and driest region in China, has been using the karez system to avoid water evaporation at the ground surface. The canals here are supplied with water from the melted ice and snow in Xinjiang's Tianshan Mountains. However, the expanding of agriculture irrigation in recent and a history of 2000 years has left Karez in desrepair. In 2009, by the third state culture relic investigation, there are 1108 wells existed in Turpan of Xinjiang , but only 278 wells are found carrying water. Renovation started at the end of 2009 and, to date, four stages of renovations, covering 108 karez well systems with a total underground canal length of 18 kilometers, have been carried out in the prefecture of Turpan. More than 600 kilometers of the underground canals were desilted and more than 10,000 vertical shafts have been repaired. Preparation for the fifth stage, which involves renovation of 15 karez wells, is under way and will start this year. (Xinhua/Zhao Ge)
