Photo taken on Sept. 28, 2015 shows Dujiangyan irrigation system in southwest China's Sichuan Province. China's four ancient irrigation sites, which are Dujiangyan irrigation system, the Lingqu Canal, the Jiangxiyan irrigation system and the Changqu Canal, have been added to the World Heritage Irrigation Structures list by the International Commission on Irrigation and Drainage (ICID). (Xinhua/Li Qiaoqiao)