What investigations have been made on the excavation and changes of the Grand Canal?
The Beijing-Hangzhou Grand Canal starts from Beijing in the north and ends in Hangzhou in the south, with a total length of about 1800 km. As for the history of the canal, it has a history of 2,490 years since Fu Cha, King of Wu, opened the canal in 487 BC. From the Yuan Dynasty to the 29th year of the Yuan Dynasty (1292), the Beijing-Hangzhou Canal marked by the completion of Huitong River and Tonghui River has a history of more than 700 years. The Beijing-Hangzhou Grand Canal connects five rivers: Haihe River, Yellow River, Huaihe River, Yangtze River and Qiantang River, and flows through six provinces and cities: Beijing, Tianjin, Hebei, Shandong, Jiangsu and Zhejiang. It is the longest man-made river in the world and one of the oldest canals. Together with the Great Wall of Wan Li, it is known as the two major ancient projects in China, which is world-famous and a symbol of Chinese civilization. The connection of the Beijing-Hangzhou Grand Canal has become a political link to maintain China's reunification, which has played an important role in China's politics, economy, military and culture for thousands of years. People have created a lot of material wealth and spiritual wealth in the process of digging canals and giving full play to their functions. The Beijing-Hangzhou Canal runs through the whole territory of Jining and flows through 7 counties and districts including Liangshan, Wenshang, Jiaxiang, Rencheng, Shizhong District, Yutai and Weishan, with a total length of about 230 kilometers. The total length of the Jinghang Canal is about 1.800 km, and Jining is located in the middle of the whole river. It started from the Yuan Dynasty to the 19th year of Yuan Dynasty (1, 282), and was dug here to connect Jizhou River and Huitong River in the 26th year of Yuan Dynasty (1, 289), and was dug three years later (1, 292). The commanding height of the Grand Canal is Wang Nan, which is known as the "water ridge" of Jining. In order to cross the "water ridge", people set up gates. "Six gates are used to control the water potential and open and close the ship." In order to solve the problem of siltation and water shortage in the Yellow River, people have taken various measures to ensure smooth transportation, such as "avoiding the Yellow River and ensuring transportation" and adding "water tanks". In order to overcome the persistent water shortage problem, people have introduced "Four Waters" to help the transportation economy, among which the construction of Daicun Dam and the introduction of Wenzhou to help the transportation economy are especially praised by the world. Of course, the Wang Nan Water Control Project is more praised by the world. Its main function is to regulate the water source and make it "divided into three emperors and seven Jiangnan". It is the highest scientific and technological project in the whole canal. Some experts believe that this project should be as famous as Dujiangyan project. Jining Canal has flourished for more than 600 years. Jining, which is located in the traffic artery, has not only become "the intersection of land and water, the crossroads between the north and the south" and "the throat control area of the Yangtze River and Huaihe River", but also become the Caohe River management center and the political and economic center of southwest Shandong, and there has been a prosperous scene of "gathering officials and businessmen and making it an economic city". A poet once described it like this: "Japanese-Chinese trade groups get together, and red and cypress bowls pile up like mountains." Businessmen seek profits, and restaurants and karaoke bars are noisy. " By the middle of Ming Dynasty, Jining had developed into a prosperous commercial city with "four thoroughfares, five capitals and one city". From the Ming Dynasty to the Qing Dynasty, Jining's commerce reached its peak. Inside and outside the city, there are thoroughfares, shops on both sides of the canal and at the mouth of the river, merchants from all over the country gather, all kinds of businesses flourish and the market is prosperous. The annual turnover is as high as 1 100 million yuan, and the market radiates around nearly 100 counties. It is one of the 33 famous big commercial cities in China during the Ming and Qing Dynasties. Jining City is located in the southwest of Shandong Province, at the junction of the Huang-Huai-Hai Plain and the mountainous areas in south-central Shandong Province. The whole terrain is high in the east and low in the west, with flat plains in the west, beautiful lakes in the south and undulating hills in the east. 1260, Kublai Khan in Yuan Shizu was the khanate, 127 1 year, the title was Dayuan, and Zhongdu (Beijing) was mostly the national capital. At this time, after a long period of war and economic depression, Dadu and North China could no longer support the population of Dadu and a large number of troops stationed in Gyeonggi, and everything had to be shipped from the south. In history, "Yuan Zaiyan is far away in the south of the Yangtze River, and all the people admire it". In this way, whether from the political or military point of view, it is imperative to reopen the North-South Canal. In the third year of Khan's reign, Kublai Khan appointed Guo Shoujing, a 3 1 year-old water conservancy expert of the Han nationality, to "exhaust all avenues" before the founding of the People's Republic of China. During the Southern Song Dynasty, Bo Yan, a general of the Yuan Dynasty, deeply felt the importance of waterways to the military and economy, so he "swam the Dadu River from the river". After the demise of the Southern Song Dynasty, with the support of dignitaries as their agents, Kublai Khan ordered Guo Shoujing to "survey the river section connecting Wen and Si since the Song and Jin Dynasties" to prepare for reopening the canal. At that time, the Tongji Canal opened in Yang Di was blocked by the rivers south of the Yellow River and the Yangtze River, so it was very difficult to repair it. At the same time, Kyoto has moved eastward to Beijing, and there is no need to bypass Kaifeng and Zhengzhou. If you move to Shandong, the canal will become a straight line, which is the closest. In this context, the target shifted to Jining. At that time, the southern end of the canal was from Hangzhou to Huai 'an, and the Sui and Tang Dynasties Canal was basically intact. It turns out that the ancient Sishui waterway above Huai 'an has been occupied by the Yellow River, but ships can enter the Yellow River and "borrow the Yellow River" to Xuzhou, and then turn the ancient Sishui waterway to Luqiao, or follow the warm and wide waterway to Jining. There is Yongji Canal (later called Yu He) opened in the Sui and Tang Dynasties in the north, and it can reach Tianjin from Xinxiang in the Yuan Dynasty. So as long as we solve the problem of about 200 kilometers from Jining to Yongji Canal, we can go from Beijing to Hangzhou. The Ming Dynasty was the heyday of canal shipping, and it was also the era with the greatest difficulties, problems and costs. At that time, the biggest problem of the canal was the interference from the Yellow River. How to correctly handle the relationship between transporting Yellow River has gone through a long process. In feudal times, water transport was the economic lifeline of the country, and the management of the canal was very important, and the management system was quite strict. When the Yuan Canal was first opened, the traffic volume was not very large and the management work was scattered. The management of canals and national water conservancy in the Yuan Dynasty was subordinate to the director of the Ministry of Industry. After the completion of Huitong River, it was first established that Jingdezhen (Zhangqiu) was in charge of water conservancy, then Jining was in charge of water conservancy, and Jining and Yuncheng were in charge of water conservancy, managing the waterway from Xuzhou to Linqing and the Yellow River in Henan and Shandong. Besides guarding city gates, some troops are also used to manage canals and maintain order. The canal was the only lifeline of the country in the Ming Dynasty, so a strict waterway management system was established. In the fifteenth year of Yongle (14 17), the Song Lizhi River was completed, and the Ministry of Industry set up a general in charge of canal navigation and water transportation. The first term of Chen's last term is as long as 20 years. In the seventh year of Chenghua, rivers and canals were separated, and rivers were in charge of waterways and canals were in charge of canal administration. The first river chief was Wang Shu, the left assistant minister of punishments. Zonghe has the right to control local officials in various provinces and to command officers and men in charge of river courses. Therefore, it is generally titled as Shangshu of the Ministry of Industry, Assistant Minister and Metropolitan Imperial History, and ranks second or third. The responsibility of the Prime Minister's river course is to dredge the river course, reinforce the dikes, and ensure the smooth passage of the waterway and the unimpeded passage of oil tankers. Specifically, it generally includes the following contents: 1, manage the water source well; 2. Manage the dam; 3. Harness rivers. This ancient Grand Canal has experienced many vicissitudes. The establishment of People's Republic of China (PRC) opened a new chapter in canal management. After the founding of New China, the water conservancy and shipping departments cooperated closely to restore the shipping of Jining ancient canal and reduce the flood disaster of the canal. According to the principle of comprehensive utilization of irrigation, drainage and shipping, they made unified planning and management of the main and tributary rivers of the canal and the Nansihu area, and made great efforts to dredge the main channel of the canal and some channels with serious siltation, such as Jining to Anshan, Jining to Nanyang and Nanyang to Gu Ting, demolished a large number of navigation-obstructing buildings, repaired damaged shiplocks, and restored the ancient canal quickly. After 50 years of large-scale renovation in New China, Jining Canal has taken on a new look. The old river channel that has been in disrepair, damaged and often flooded for a long time has been preliminarily rectified, and a new river channel with multiple functions such as flood control and waterlogging elimination, water diversion and irrigation, water supply and transportation, shipping development and tourism has been built. Great economic, social and ecological benefits have been achieved, and great contributions have been made to the benefit of Jining people and the sustained and rapid development of Jining regional economy. Jining Shipping Administration was also established in the era of Grand Canal Management (1952), and it has a history of 50 years. These 50 years have witnessed the continuous development of Jining shipping from small to large and from weak to strong, and also witnessed the continuous struggle of generations of Jining shipping people. After 50 years of struggle, Jining shipping industry has become an important part of regional economic development. At present, the city has more than 1 1000 ships of various types, the navigation mileage of navigation channels reaches 1 100 kilometers, there are1ports, 65 operating areas and the annual designed throughput capacity is1300. Jining Waterway Administration, as the government department in charge of shipping of Jining Municipal Government, will carry forward the fine tradition and style of Jining's shipping struggle, earnestly practice Theory of Three Represents under the leadership of Jining Municipal Party Committee, Municipal Government, Provincial Communications Department and Port and Shipping Bureau of ministries and agencies, keep pace with the times, speed up development, and strive to speed up Jining's economic strength, cultural awareness and group structure, and build the Shandong section of the Beijing-Hangzhou Canal into an industrial belt, a cultural belt, a tourist belt and a scenic belt.