Chapter 29 Section 2 The establishment of the three major canal systems in the Western Han Dynasty

Chang'an was the capital of the Western Han Dynasty, and Guanzhong was the main supply place for daily necessities such as grain for the officials of the capital, the army, and the common people.The Western Han Dynasty attached great importance to the development of the northwest frontier, and Guanzhong was the base of the expansion, shouldering the heavy responsibility of providing grain and fodder.Therefore, in the Western Han Dynasty, especially during the reign of Emperor Wu of the Han Dynasty (140-87 BC), in order to meet the needs of all parties for grain and fodder, in addition to digging canals and transporting grain from the east to the customs, the more important thing was to Additional irrigation projects were built in Guanzhong to expand the area of ​​irrigated land and increase local food production.This formed an unprecedented climax of water conservancy construction in Guanzhong. In just a few decades, a large number of farmland water conservancy projects such as Longshou Canal, Liufu Canal, Baiqu Canal, and Chengguo Canal were dug.

In the Western Han Dynasty, the Longshou Canal was the earliest to be drilled for irrigation canals in Guanzhong, about the period from Yuanshou to Yuanding of Emperor Wu of the Han Dynasty (122-111 BC).At that time, a man named Zhuang Xiongzhen wrote a letter to the emperor, reflecting the requirements of the people of Linjin (now Dali area), hoping to open a channel to divert Luoshui to irrigate more than 10,000 hectares east of Chongquan (southeast of today's Pucheng). saline land.Emperor Wu adopted this opinion and sent more than 10,000 soldiers to dig canals.They opened the canal from Zhengxian County (the southwest of today's Chengcheng County) to the foot of Shangyan Mountain (now Tiexian Mountain). Due to the loose soil, the bank of the pierced open channel was easy to collapse, and the well channel structure was used instead.The well channel consists of two parts: an underground channel and a shaft.The former is a water route, and the latter is convenient for people to go up and down, unearth and light when digging a canal.The deepest shaft reaches more than 40 feet.Because many skeleton fossils were excavated during the digging of the canal and used as keel, it is called Longshou Canal.After the channel was dug through, the effect of irrigated fields was not significant because the landslide problem could not be solved.But it created advanced well technology.

Liufu Canal was built in the sixth year of Emperor Yuanding (111 BC) by Zuo Neishi Ni Kuan.Small in scale, it is the general term for the six auxiliary channels.Later generations believed that it was used to divert small water from Yeyu, Qingyu and Zhuoyu to irrigate the farmland in the north of the upper reaches of Zhengguo Canal.These farmlands are relatively high-lying and cannot be irrigated by the Zhengguo Canal.After the Liufu Canal was completed, in order to better play the role of this project, according to the "Hanshu Biography of Ni Kuan", he stipulated "water orders".This is the earliest water system in my country recorded.

In the 16th year after the completion of the Liufu Canal, that is, in the second year of Emperor Wu Taishi (95 BC), the construction of the Baiqu Canal started.This project was proposed and presided over by Bai Gong, the doctor of Zhao Zhong.The head of the canal is also at the mouth of the valley, and the canal is in the south of Zhengguo Canal, flowing southeast, passing through Chiyang (where the government is located in the northwest of Jingyang County), Gaoling, and Liyang (where the government is located in the northeast of Lintong County), and then into Weishui.It is 200 miles long and irrigates more than 4,500 hectares of farmland beyond the reach of Zhengguo Canal.After the completion of the Baiqu, Gukou, Chiyang and other counties became high-yield areas without drought or flood because of the irrigation of the Zheng and Baiqu.At that time, there was such a folk song popular in the local area, praising the functions of the two canals:

Although the irrigated area of ​​the Baiqu Canal is much smaller than that of the Zhengguo Canal, it is far more reasonable than the Zhengguo Canal due to its larger slope, so it is not as easy to be blocked by sediment as the Zhengguo Canal. In the Song Dynasty, there was still some development, but the downstream of Zhengqu was soon scrapped. "One stone in Jingshui contains several buckets of mud." The high mud content can reduce alkali and fertilize the field, and the effect is indeed remarkable in a short period of time.But we can’t just see the advantages and ignore the disadvantages. In the long run, it is easy to silt up the canals and farmland after a long period of time, causing the fields to be higher than the canals and the canals to be higher than the dikes, which will inevitably destroy the entire irrigation system.

Another important farmland water conservancy project in the Guanzhong area newly built in the Western Han Dynasty is the Chengguo Canal.When was it built and who was in charge of this project, there is no clear record in the history books, only that it was built during the reign of Emperor Wu.This is a large-scale irrigation canal with the Weishui River as its water source. It is located in the north of the Weishui River. The head of the canal is in Mei County. The southeast of the county) and other counties, the end of the canal is connected to the Menglong Canal of Shanglinyuan.The length of the Chengguo Canal is slightly smaller than that of the Bai Canal, and the irrigated area is about 10,000 hectares, more than double that of the Bai Canal.Later, it developed into the most important irrigation channel in Guanzhong.Shanglin Garden is located in the west of Xianyang, with a circumference of 300 miles, across the Wei River from north to south, and was the place where emperors shot, hunted and played in Qin and Han Dynasties.Menglong Canal is a waterway in the royal garden, which is used for garden watering and boating.

In the long history, Guanzhong Water Conservancy has always been composed of three canal systems, namely the Yinjing Canal System with Jingshui as its water source, the Weishui Canal System with Weishui as its water source, and the Yinluo Canal System with Luoshui as its water source.It can be said that these three canal systems have been basically formed during the Western Han Dynasty. In addition to the famous irrigation projects mentioned above, a number of small irrigation canals, such as the Lingzhi (zhizhi) canal, were also built in the south of the Wei River during Emperor Wu's reign.They use the mountain stream originating from Nanshan as their water source.

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