The Zhengguo Canal, Zhengguoqu or Chengkuo Canal , named after its designer, Zheng Guo

Zheng Guo

Zheng Guo or Cheng Kuo was a hydraulic engineer from the ancient Chinese kingdom of Han who designed the Zhengguo Canal in the kingdom of Qin during the Warring States Period. The canal remains to this day, despite having been constructed in the third century BC. The canal was originally designed...

, is a large canal located in Shaanxi

Shaanxi

' is a province in the central part of Mainland China, and it includes portions of the Loess Plateau on the middle reaches of the Yellow River in addition to the Qinling Mountains across the southern part of this province...

 province, China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. The canal irrigates the Guanzhong

Guanzhong

Guanzhong , or Guanzhong Plain, is a historical region of China corresponding to the lower valley of the Wei River. It is called Guanzhong or 'within the passes' to distinguish it from 'Guandong' or 'east of the pass', that is, the North China Plain. The North China Plain is bordered on the west by...

 plain, north of Xi'an

Xi'an

Xi'an is the capital of the Shaanxi province, and a sub-provincial city in the People's Republic of China. One of the oldest cities in China, with more than 3,100 years of history, the city was known as Chang'an before the Ming Dynasty...

. Together with the Dujiangyan Irrigation System

Dujiangyan Irrigation System

Dujiangyan is an irrigation infrastructure built in 256 BC during the Warring States Period of China by the Kingdom of Qin. It is located in the Min River in Sichuan province, China, near the capital Chengdu. It is still in use today to irrigate over 5,300 square kilometers of land in the region...

 and Lingqu Canal

Lingqu Canal

The Lingqu Canal is located in Xing'an County, near Guilin, in the northeastern corner of Guangxi Province, China. It connects the Xiang River with the Lijiang , which in its turn continues toward the Xijiang), and thus is part of a historical waterway between the Yangtze and the Pearl River...

, it is one of the three biggest water conservation projects before the Qin Dynasty

Qin Dynasty

The Qin Dynasty was the first imperial dynasty of China, lasting from 221 to 207 BC. The Qin state derived its name from its heartland of Qin, in modern-day Shaanxi. The strength of the Qin state was greatly increased by the legalist reforms of Shang Yang in the 4th century BC, during the Warring...

 in ancient China. The canal connects the Jing and Luo rivers, northern tributaries of the Wei River

Wei River

The Wei River is a major river in west-central China's Gansu and Shaanxi provinces. It is the largest tributary of the Yellow River and very important in the early development of Chinese civilization....

.

History

Historian Sima Qian

Sima Qian

Sima Qian was a Prefect of the Grand Scribes of the Han Dynasty. He is regarded as the father of Chinese historiography for his highly praised work, Records of the Grand Historian , a "Jizhuanti"-style general history of China, covering more than two thousand years from the Yellow Emperor to...

 in his Records of the Grand Historian

Records of the Grand Historian

The Records of the Grand Historian, also known in English by the Chinese name Shiji , written from 109 BC to 91 BC, was the Magnum opus of Sima Qian, in which he recounted Chinese history from the time of the Yellow Emperor until his own time...

 wrote of the Zhengguo Canal:
The plan to drain the resources of the State of Qin

Qin (state)

The State of Qin was a Chinese feudal state that existed during the Spring and Autumn and Warring States Periods of Chinese history...

 back-fired as Qin successfully completed the canal, which irrigated c. 27 000 square kilometres of additional agricultural land, providing the kingdom with sufficient resources to increase the size of its already massive armies. To this day the land surrounding the Zhengguo Canal is extremely fertile.

By the time of its completion in 246 BC

246 BC

Year 246 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Crassus and Licinus...

, during the Han Dynasty

Han Dynasty

The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...

, the canal was already much silted. Under the supervision of Bai Gong, a new canal was cut to feed the irrigation in 95 BC

95 BC

Year 95 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Crassus and Scaevola...

. For the next 2000 years re-cutting and moving the canal's feeder mouth upstream of the Jing River became a pattern as silt built up in the canals and river deepened its bed, diminishing water flow and the efficiency of the system.