The Dujiangyan Irrigation System is an ancient engineering marvel located in the Chinese province of Sichuan. Constructed over 2,200 years ago, it is one of the oldest and most successful water control projects in the world. Here are some interesting facts about the Dujiangyan Irrigation System:
Purpose and Design:
- The primary purpose of the Dujiangyan Irrigation System was to control the waters of the Min River, prevent flooding, and ensure a stable water supply for agricultural needs.
- The system was designed to harness the natural force of the river, utilizing its water flow instead of damming it.
- It consists of a sophisticated network of canals, levees, and diversion structures, strategically placed to efficiently distribute water to farmlands.
Legendary Origin:
- According to legend, the Dujiangyan Irrigation System was built by a renowned engineer named Li Bing and his son. Li Bing was appointed by the local king to find a solution to the frequent floods plaguing the region.
- The story goes that Li Bing received divine guidance from a local deity and designed the system to separate the turbulent Min River into two channels, using a fish-mouth-shaped levee.
Fish Mouth Levee:
- The key feature of the Dujiangyan Irrigation System is the fish mouth levee, known as Yuzui. It is a sediment-diverting structure that splits the river into an inner and an outer channel.
- The wider outer channel serves as a spillway during floods, allowing excess water to bypass the farmlands and flow harmlessly downstream.
- The narrower inner channel carries the majority of the water to the irrigation canals, ensuring a regulated and controlled water supply.
Qingcheng Mountain Diversion:
- The Dujiangyan system also includes the ingenious Qingcheng Mountain Diversion, where a man-made channel was carved through the mountain to divert water from the Min River.
- This diversion channel helps to regulate the water supply during dry seasons, ensuring a continuous flow of water to the irrigation canals and farmlands.
Natural Filtration:
- One of the remarkable aspects of the Dujiangyan system is its natural filtration method.
- At the entrance of the inner channel, a system of large bamboo screens known as Baopingkou was constructed to filter out debris, preventing clogging of the canals.
- The screens allow clean water to pass through while trapping sediment, ensuring the irrigation canals receive clear water.
Continuous Operation:
- The Dujiangyan Irrigation System has been in continuous operation for over two millennia, making it a testament to its exceptional engineering and longevity.
- Even today, the system continues to provide irrigation water to vast agricultural areas in the region, contributing significantly to Sichuan’s agricultural productivity.
UNESCO World Heritage Site:
- In recognition of its historical and engineering significance, the Dujiangyan Irrigation System was designated as a UNESCO World Heritage Site in 2000.
- The system is celebrated not only for its functionality but also for its harmonious integration with the natural landscape, reflecting the ancient Chinese philosophy of balancing human needs with nature.
The Dujiangyan Irrigation System stands as a testament to the ingenuity and wisdom of ancient Chinese engineers. Its enduring success and cultural importance make it a remarkable landmark and a symbol of sustainable water management.