What if I told you that Chengdu owes its agricultural prosperity to an ancient engineering marvel? That marvel is near us. It is the Yan’erhe Reservoir. It is more than just a body of water. Yan’erhe Reservoir is a testament to human ingenuity and our enduring relationship with nature.
The Yan’erhe Reservoir’s story begins over two millennia ago. Around 256 BC, the Kingdom of Qin sought to tame the Min River. The Min River was known for its devastating floods. These floods disrupted agriculture and threatened lives. Li Bing, an official of the Qin Kingdom, stepped forward with a bold plan. He would create a system to control the river’s flow.
King Zhao of Qin funded Li Bing’s project. Tens of thousands of laborers worked tirelessly. They reshaped the landscape. Li Bing’s solution was not to simply dam the river. Instead, he devised a way to channel and divide the water. This innovative approach would manage floods and irrigate the land.
The Dujiangyan Irrigation System, of which Yan’erhe Reservoir is a part, consists of three main components. First, the Yuzui or Fish Mouth Levee divides the river into inner and outer streams. This levee directs 60% of the water into the irrigation system during the dry season. During floods, it reduces the flow to 40%. The outer stream flushes out silt and sediment.
Second, the Feishayan or Flying Sand Weir connects the inner and outer streams. This weir drains excess water from the inner stream to the outer stream. It also removes silt. The swirling flow of water prevents flooding.
Third, the Baopingkou or Bottle-Neck Channel distributes water to the farmlands. This channel, cut through a mountain, acts as a check gate. It controls the water flow. Excess water flows over the Flying Sand Fence.
The construction of the Bottle-Neck Channel was particularly challenging. Workers used fire and water to crack the rocks. It took eight years to carve a channel 20 meters wide. The Dujiangyan Irrigation System made Sichuan the most productive agricultural region in China.
The Dujiangyan has provided flood control, irrigation, and water transport. It has been in use for over 2,250 years. It now irrigates 668,700 hectares of farmland. Together with the Zhengguo Canal and the Lingqu Canal, it is one of the “three great hydraulic engineering projects of the Qin.”
The system’s success led to a laid-back attitude among the people of Chengdu. Regular harvests ensured plenty of free time. The system was rebuilt after the 1933 Diexi earthquake. In 2000, it became a UNESCO World Heritage Site.
The Yan’erhe Reservoir stands as a reminder of Li Bing’s vision. It showcases the power of engineering to transform lives. The Yan’erhe Reservoir continues to shape the region’s identity. The reservoir helps to promote agricultural prosperity. It is a place of scenic beauty. It offers us a chance to reflect on our relationship with the environment.