An ancient irrigation system that dates back 4,000 years has been unearthed in Chengdu of Southwest China's Sichuan province.
The system, with a 147-meter-long bank protection dam, was discovered at a real estate construction site in Wenjiang District of the city. It is 14 meters wide at the bottom, 12 meters at the top and 1.3 meters high with eight grooves dug by hand.
The dam is the earliest irrigation system in the areas along the upper reaches of the Yangtze River. It is 2,000 years older than the Dujiangyan irrigation system.