In the first 246 years (the first year of the King of Qin), the King of Qin adopted the advice of Zheng Guo, a Korean, and Zheng Guo presided over the construction of a large irrigation canal, which led water mirror water from the west to Luoshui in the east, with a total length of more than 300 miles. Jinghe River rushes out from the mountainous area of northern Shaanxi, flows to Liquan and enters the Guanzhong Plain. The plain is hundreds of miles from east to west and dozens of miles from north to south. The plain is slightly higher in the northwest and lower in the southeast. Zheng Guoqu made full use of this favorable terrain and began to build a main canal at Gukou in the northeast of Liquan County, so that the main canal extended eastward along the northern foot. Naturally, the main canal is located in the highest part of the irrigation area, which not only controls the irrigation area to the maximum extent, but also forms a full gravity irrigation system, which can irrigate more than 40 thousand hectares. Since the excavation in Zheng Guoqu, the head of the main canal has been gradually filled up due to sediment deposition, and water cannot enter the channel. Since the past dynasties, the place where the river enters the canal has been constantly changing at Gukou, but the channel of the main canal below Gukou remains unchanged.
The role of Zheng Guoqu lies not only in its irrigation efficiency of 100, but also in its pioneering practice of diverting water from Jingxing, which has a far-reaching impact on later irrigation. After Qin Dynasty, the water conservancy facilities here have been continuously improved in successive dynasties: Baigong Canal in Han Dynasty, Sanbai Canal in Tang Dynasty, Fengli Canal in Song Dynasty, Shiqu Canal in Yu Wang in Yuan Dynasty, Guanghui Canal and Tongji Canal in Ming Dynasty and Longdong Canal in Qing Dynasty. There was a folk song in the Han Dynasty: "Where is the field? Taniguchi Chiyang. Zheng is in the front and Bai Qu is in the back. Raise the bell for the cloud and raise the canal for the rain. The water mirror is a stone, its mud is a bucket, it is irrigation and dung, and it grows my millet. Food and clothing capital, the mouth of hundreds of millions. " Zan is a water diversion project. During 1929, there was a severe drought in Guanzhong, Shaanxi Province, with six crops in three years and starvation everywhere. It is urgent to draw water from Jingxing for irrigation. Mr. Li Yizhi, a well-known water conservancy expert in modern China, was ordered at a critical moment, and resolutely took up the important task of repairing Jinghui Canal in the former site of Zheng Guoqu. Under his personal leadership, the canal broke ground in June 65438 +0930+February 65438, and thousands of migrant workers worked hard for nearly two years, finally building today's Jinghui Canal. 1June, 932, water was released to irrigate the fields, and the water intake was 16m3/s, which could irrigate 600,000 mu of land. At this point, we will continue to benefit the people.