Which two canals were dug in the Song Dynasty? What is the purpose of its opening?

The Bianhe River, one of the "Four Rivers of Water Transport", namely the Tongji Canal, remains basically unchanged. To the west of Kaifeng, the Yellow River flows eastward from Biankou, Yin He County (now the Yellow River Beach in Liugou Village, Xingyang, Henan Province), enters the Watergate on the riverside outside Kaifeng (now the north of Zhengmenkou Village, Kaifeng, Henan Province), passes through the inner city, and leaves the city from the Watergate in Bianhe Village, Waiguo (now the north of Yangmen Village). The river to the east of Kaifeng generally follows the general trend of Huiji River today, to the south of Sizhou to Huaihe River (now northeast of Xuyi, Jiangsu, has sunk in Hongze Lake). Cao Cao was introduced into the Jianghu in the Northern Song Dynasty, benefiting from making a fortune for a long time and working as a department store in Shanze. He learned that Bianhe was the foundation of the founding of the People's Republic of China. However, because the Bianhe River is connected with the Yellow River, it needs to be maintained from time to time because of its fluctuation and sediment. The Bianhe River construction in the Northern Song Dynasty 170 years includes:

① Water source construction. Because the Yellow River doesn't often turn back, the mouth of the river changes every year. In the Northern Song Dynasty, the permanent gate was changed to manually control the depth and width of the side mouth to control the flow: when the side river rises, the side mouth will rise to reduce the inflow of water from the Yellow River; When the river falls, it will dig deep and wide side mouths to increase the water inflow. Set up a chief supervisor and serve for a long time. This project consumes a lot of manpower and financial resources, so we must find new water sources. In the second year of Emperor Taizu's Stegosaurus (96 1), it was dredged and injected into the Bianhe River. In the second year of Zongshen Yuanfeng (1079), the Bianhe project in Luo Qing started again. From Shagukou, Rencun Village, Gongxian County to Bianhekou, Yin He, the Luoshui River opened for 50 miles, and the water source of the Yellow River was cut off. For more than ten years, due to the low sediment concentration in Luoshui, the navigation of Bianhe River has been improved to some extent. In order to transport economically, one pit after another ("water tanks") was built along the Bianhe River.

② River engineering. Due to the long-term diversion of economic transportation to the Yellow River, the Bianhe River is silted up and the riverbed is getting higher and higher. Xunhe River dredging projects are frequent. These measures include: manual excavation, almost once a year, slate people placed at the bottom of the river bed to remember the depth standard of the underground. Narrow river project, from Xiashuimen in the southeast of Kaifeng City to the Bianhe River bank in Yingtianfu section, is wide and shallow, with astringent and silted water. From the first year of Jiayou (1056), wooden beams were placed along the coast to narrow the river body, speed up the flow and slow down the siltation. As a routine system, soldiers were sent to patrol the border area day and night in the Northern Song Dynasty, and the project required "as little sand as possible". A large cone was used to test the actual situation of the embankment, and a short wall was built along the river as a restriction to prevent people from falling, and willows were planted along the embankment to stabilize the embankment foot. The river channel along the Bianhe River will be controlled by floodgates to prepare for flood discharge and reduction, and all projects will be managed by the shore lifting and releasing company.

The annual traffic volume of Bianhe River in the Northern Song Dynasty increased with the extravagance and waste of the imperial court. From several hundred thousand stones in the early Song Dynasty to seven million stones in the early years of Song Zhenzong Dazhong Xiangfu (1008), it remained at six million stones. In the Song Dynasty, every ten to thirty waterwheels were used as the key link, and transportation was organized by the method of "key link transportation". Every year, thousands of public and private ships return to the Bianhe River and sail like a forest, which not only connects the political center and economic center of the country, but also promotes the material exchange and social and economic development along the coast, and plays an important role in expanding economic and cultural exchanges between China and foreign countries.

In the late Northern Song Dynasty, the shallow elevation of Bianhe River became more and more serious. From Dongshuimen in Kaifeng to Xiangyi, the bottom of the river is more than ten feet higher than the flat land outside the dike. Seen from the bottom of the river, the residents are in a deep valley. After the Jin Dynasty destroyed the Northern Song Dynasty, the Bianhe River lost its value of grain transportation and was allowed to deposit. Water can still travel to the east of Lingbi, and the riverbed above Suzhou has become a land avenue, and the Central Plains waterway artery that has been maintained for more than 500 years has finally disappeared.

Huimin River is the collective name of Min River and Cai River Canal in the southwest of Kaifeng in the Northern Song Dynasty. One of the "Four Rivers of Water Transport". In the early Song Dynasty, when Fang Yufu and Shi Jing were fighting in the southeast, they needed money from the counties in the west of Beijing. In the second year of Stegosaurus (96 1), the Minjiang River was cut. It started in Xinzheng County, Henan Province, led the Pi River (now Shuanghe River) to the northeast, passed through Songlou (now south of Wei Weichuan Town, Henan Province) and Zhuqu (now Wei Zhuqu Township), reached Pipagou (namely the headwater of Cai Heyuan) ten miles west of Kaifeng City, entered the city from Puji Watergate, the outer wall of Kaifeng House in Tokyo, and left the city from Guangli Watergate. Caihe River is used in the following sections, namely the ancient canal and the gap. Cai Henan flows through the customs and fees, reaches Caikou Town (now the area from Doumenji in Huaiyang to Xiangcheng), and enters. In the second year of Gande (964), water was diverted from the north canal of Changshe (now Xuchang, Henan) to Fujian, so as to broaden the water sources. The excavation of Minshui not only increased the water source of Caihe River, but also transported materials from Xu and Ruzhou to Beijing. In the sixth year of Kaibao (973), Minshui was changed to Huimin River, later called Minshui and Caishui.

In the Northern Song Dynasty, the Fangcheng Canal was dug twice, and the southwest and Hancao roads were opened, and an attempt was made to plunge the Baihe River into the Huimin River, but it failed because of its high terrain and complex terrain. On the contrary, the canal connecting Rushui, Shui Ying and the middle reaches of Chaihe River was built three times. Shangshui, a tributary of Rushui River, was introduced into Shui Ying from Huihe Town (now Xiaoyao Town, Xihua, Henan Province) to the north, and then flowed eastward through Zhucaihe River, Changping Town, Xihua County, so that the water transportation between southwest Henan and Kaifeng no longer bypassed Caikou, saving 500 miles. This canal also belongs to Huimin river system.

Huimin River is an important canal connecting the capital and southwest China during the Northern Song Dynasty. It loses 600,000 grains in countries such as Chen, Ying, Xu, Cai, Guang and Shou every year, in addition to a lot of money, silk, salt and tea, especially in the capital. After the Jin Dynasty destroyed the Northern Song Dynasty, the Bianhe River was blocked, but the Huimin River continued to serve as an important waterway for the Jin Dynasty to reach the Huaihe River. From Yuan Dynasty to Ming Dynasty, Cai gradually disappeared under the influence of the Yellow River.

Guangji River is a river in Zhang Wu, and it is one of the "four major water transport rivers" in the Northern Song Dynasty. In the Five Dynasties, in order to strengthen the material transportation between Kaifeng, the capital of Shandong Province, and the northern coastal areas of Shandong Province, Chai Rong, Zhou Shizong, drained Bianshui to Baigou (the old water supply road in the south) in the north, and then flowed into Jishui in the east, thus connecting the waterways of Qilu. The riverbed is spread five feet, commonly known as the "Five-foot River". The Northern Song Dynasty was founded, and the southeast was uneven. Qilu Waterway continues to be regulated, and it enters Gyeonggi in the west, cuts off the Bianhe River, and then flows into the river in the east of Kaifeng to increase the water volume. At the age of 20, her husband was transferred to dredge the river and build a dam along the river to help transport. In the sixth year of Kaibao (973), it was renamed Guangjihe.

The Guangji River starts from Xiantongmen in the northeast of Bianjing Waiguo, flows eastward to Jeju and Cai Zhen (now southwest of Shandong Yuncheng), enters the water margin and receives water. At the beginning of the founding of the Northern Song Dynasty, the water transport of Guangji River played an important role, and the annual water transport capacity increased from100000 stone to 670000 stone. The millet and silks in seventeen states of Tokyo were transported to the capital by Guangji River, and it was established in the southeast that Guangji River was only transported to Taikang, Xianping and Weishi counties. After the middle of the Northern Song Dynasty, the Yellow River invaded south many times, and the waterway of Guangji River was shallow and astringent, which greatly reduced the transportation capacity and was abandoned in the Jin Dynasty.

Jinshui River, an artificial diversion canal in the west of Kaifeng in the Northern Song Dynasty. In the second year of Jianlong (96 1), a canal was dug to bring Huangdui Mountain in Xingyang into Beijing and Suoer East to cross Zhongmou. Every 100 miles, we arrived in Jingxi, crossed the tributary with a trough, and merged into Zhangwu River in the east, named Jinshui River. This canal is clear, and when you enter the palace, you drink water for the capital; Secondly, it is of little significance to supplement the water flow of five feet. History says: Bian, Huimin, Jinshui and Guangji River are the four major waterways, or Bian, Huimin, Guangji River and Yellow River are collectively called the four major waterways, thus forming a canal system centered on Kaifeng, the capital city.