Chapter 22 Section 4 Water Conservancy of Du River in Yuan, Ming and Qing Dynasties

Since Li Bing founded the Dujiang Water Conservancy Project, through the Han Dynasty to the Tang and Song Dynasties, the main building material has always been the bamboo gabion, which is "broken bamboo as a cage and filled with stones".Bamboo and stone can be obtained locally, the construction is simple, the texture is soft, and it is suitable for the changeable riverbed of the Minjiang River.But its shortcomings are also very prominent, not strong, easy to be washed away by floods, not resistant to corrosion, and must be replaced frequently.In order to change these defects, since the Yuan Dynasty, people have put forward the idea of ​​replacing the pebbles in bamboo cages with materials such as cast iron and strip stones.Ji Dangpu (Mongolian) and Zhang Hong, the judge of Guanzhou, used this method to repair the weir. After a small-scale experiment, they proved that it was feasible. In the first year to the second year (1335-1336 AD), ), implemented throughout the overhaul project.The main hydraulic structures at that time were mostly stone structures built with lime mortar, and the stones were connected with cast iron ingots, and the gaps were filled with tung oil mixed with lime and hemp silk.Among them, the key project - the water diversion fish mouth of Neijiang River, even adopts an all-iron structure. They used 16,000 jin of pig iron to cast a large iron turtle as the water diversion fish mouth.This is a major reform of building materials in the Dujiang Water Conservancy Project, and an attempt to replace temporary buildings with permanent buildings.It is indeed very successful, and it has made the Dujiang Water Conservancy Project a situation that has not been seen before and has not undergone major repairs for decades (Figure 6).

Casting fish mouths with all iron developed in the Ming Dynasty.Although the iron tortoise and fish mouth in the Yuan Dynasty was very strong, the gravel layer of the Minjiang river bed was very thick. When the iron tortoise and fish mouth was installed, although some treatment was done to the foundation, the depth of the excavation was not enough. When it is washed out by the flood, the iron turtle will not work.Therefore, when casting iron fish mouths in the late Ming Dynasty, in addition to increasing the amount of iron used for fish mouths, attention was also paid to foundation treatment.The project was carried out in the 29th year of Jiajing (AD 1550), and was presided over by Shi Qianxiang, the inspector, and Liu Shoude, the magistrate of Chongning County.The foundation pit was cleaned first, and more than 300 cypress piles were densely planted in the foundation pit, filled with gravel, and then thick stone slabs and cast iron slabs were built on it.On this basis, two big iron bulls with "first joint and last division" were cast.This project shared 72,500 jin of iron.At that time, the following inscriptions were cast on the cattle.This project was still destroyed decades later because the foundation was not deep enough.

In addition to the canal head project, the middle and late Ming Dynasty also paid more attention to the construction of the canal system project.According to statistics, during the reign of Zhengde (AD 1506-1521), there were 471 weirs in the whole irrigation area. More than 100 years later, in the reign of Tianqi (AD 1621-1627), the number of weirs increased to 608.One of the characteristics of the Dujiang water conservancy project is to divide water by weirs, and every time we add a weir, a canal will be added.The increase of the weir indicates the development of the canal system and the expansion of the irrigated area.

In the late Ming and early Qing Dynasties, wars continued and the Dujiangyan project was severely damaged.Since the late Kangxi period, the political situation in Sichuan has been relatively stable, and the Dujiang water conservancy project has been restored and developed.In the Qing Dynasty, Altai and Ding Baozhen made great contributions to the construction of Dujiang Water Conservancy. Altai, Manchuria is the Yellow Banner people.Governor of Shandong Province for seven years, he built water conservancy and made great achievements.After being promoted to governor of Sichuan, he attached great importance to the construction of the Dujiang water conservancy project.From the 28th to the 31st years of Qianlong (1763-1766 AD), important attempts were made to strengthen the big fish mouth and store water in the upper reaches of the Minjiang River.In view of the fact that the Yuzui was destroyed in the past, it was not closely related to the foundation works. Therefore, when the Yuzui was built, he asked for improvement of the foundation works, and ordered the sand and stone to be excavated to be three feet deeper than in the past.In order to ensure water for spring farming in the Sichuan Plain, he ordered the construction of weirs in the mountains upstream of the Minjiang River to store water.This measure can not only ensure the water used for spring farming, but also have the function of blocking flood and sand in summer and autumn.

In the project of governing Dujiangyan in the Qing Dynasty, from the end of the third year of Guangxu to the beginning of the fourth year (January-April 1878), the overhaul presided over by Ding Baozhen, governor of Sichuan, should be said to be very outstanding.Ding's projects were large and thorough. He remodeled some important buildings, using mortar to lay stones and "iron ingots" to replace pebbles and bamboo cages.Among them, Dujiang Yuzui is built into a huge monster with a depth of one foot, a height of two feet and a length of 16 feet, which is very strong.The river bed was dug deep and high embankments were built.The river bed was dug to a depth of 1.2 to 1.4 feet, and the excavated earth and rocks amounted to more than 400,000 square meters (one foot in length and one foot in width, and one foot in thickness is one city square).The height of the embankment increased by more than 1.6 feet, and the total embankment of the inner and outer rivers exceeded 12,000 feet.Due to the good quality of the project, although in.

After more than 2,000 years of hard work, Dujiang Irrigation District has reached the best level in history.During the Daoguang period (1821-1850 A.D.), the irrigation districts developed to Chengdu, Huayang (the seat of the government today is Chengdu), Hanzhou (the seat of the government is now Guanghan), Jintang, Shuangliu, Xinjin, Meizhou (the seat of the government is now Meishan County), Xindu, Xinfan, Wenjiang, Pixian, Chongning (northwest of Pixian), Pengxian, Guanxian, Chongqing and other 15 prefectures and counties have an irrigated area of ​​nearly 3 million mu. During the period of the Republic of China, due to the influence of war and political instability, its irrigated land area was slightly reduced, and it was 2.8839 million mu in 1949.

In ancient times, although the Dujiang water conservancy construction had made great achievements, due to historical limitations, it was impossible to have an overall plan for the construction of this project at that time, and it was impossible to have advanced hydraulic technology.Therefore, such situation and problem are necessarily produced: on the one hand.On the other hand, in the vast western Sichuan region, only a small part of the farmland is irrigated by the Minjiang River, and most of the farmland is still Wangtiantian, and agricultural production is not guaranteed. After the founding of the People's Republic of China, the role of modern science and technology was brought into full play, and the irrigation system of the Dujiang River was re-arranged from the overall situation. Large-scale steel control gates, water delivery tunnels and regulating reservoirs were built, so that most of the Minjiang River's water can be obtained. took advantage of.By the mid-1980s, the irrigated area of ​​Dujiang Water Conservancy had increased rapidly to 11 million mu.In addition, it also provides industrial water and domestic water for modern cities.

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