The Dujiangyan Irrigation System is the oldest and only surviving dam-free irrigation system in the world. It uses natural topographic and hydrological features to solve problems of diverting water for irrigation, draining sediment, flood control, and flow control without the use of dams, producing comprehensive benefits in flood control, irrigation, water transport and general water consumption. Begun over 2,250 years ago, it is producing increasingly greater benefits. The Dujiangyan Irrigation System harmlessly makes use of natural resources and converts harm into benefit, achieving harmony between mankind, land and water. It is the only surviving great ancient “ecological project” in the world.