The Changqu Canal (the Bai Qi Canal)
2022-06-16 11:09

The Changqu Canal

In the city of Xiangyang in China, there is a 2,000-plus-year-old irrigation system where reservoirs and ponds are like melons, and canals are like vines. Because the main canal ran over 50 km, this irrigation system is called the Changqu (meaning “long canal” in Chinese) .


Bai Qi, a general of the Qin Dynasty (221-206 BC), had the weirs and canals built in 279 BC and used the water to inundate the enemy troops. Once built for war, this project later became an important irrigation system in the Xiangyang Plain. Changqu Canal was also named the Bai Qi Canal to commemorate its original creator.   


General Bai Qi

In the 3rd century, the Muqu Canal was built to the north of the Changqu Canal, which diverted water from the Yanshui River, another tributary of the Han River. The Changqu Canal and the Muqu Canal were two canal systems connected with each other.   A large irrigation district with 40,000 hectares was developed at today’s Xiangyang and Yicheng. The Xiangyang-Yicheng Plains became a “bread basket” in the middle reach of the Han River.  


The connected Changqu and Muqu Canals

After over 600 years of gradual improvement from the Qin and Han dynasties until the Southern and Northern Dynasties (AD 420-589), the Changqu and Muqu Canals had already become a regional irrigation project with water diversion and storage functions by the 5th century at the latest. From the 13th century to the early 20th century, the Changqu and Muqu Canals had always been managed under the system of governmental supervision and private management. However, the canals fell into disrepair in the 19th century because of the sharp conflict between the needs of upstream water transport and downstream irrigation. They were finally rebuilt at the original sites in the mid-20th century.

The Changqu Canal irrigation System consists of headworks, canal system as well as regulation and storage works. The headworks are located at the confluence of the main stream of the Manhe River and its tributary Qinglianghe River near Wu’an Town in Nanzhang County. The main canal runs through the middle of the irrigation district. 


The melons-on-vines irrigation system

At present, there are 15 medium and small sized reservoirs and 2,671 weirs and ponds in the irrigation district. The reservoirs are connected to the Changqu Canal through ditches and canals controlled by water gates. The Changqu Canal is like a vine, and the reservoirs, weirs and ponds connected to it are like melons. The project has become a typical melons-on-vines irrigation system in South China. During non-irrigation season, barrages divert river water into canals and thereby feed into reservoirs and ponds. During the irrigation season, the reservoirs and ponds supply water to the Changqu Canal. The repetition of this cycle raises the utilization rate of the reservoirs and ponds and guarantees water supply for irrigation.  


The Changqu Canal

The sustained use of the Changqu Canal for two thousand years has made Xiangyang a fertile land and has created a rich and diversified local culture. Memorial temples have been built long the canal to worship people who contributed to the construction and maintenance of the canal, so as to encourage later generations to build irrigation project and develop agriculture. The Changqu Canal still tells its time-honored legend nowadays, even though thousands of years have elapsed.