Chengdu, the capital of Sichuan Province, administers 11 municipal districts, 4 counties, and 5 county-level cities. Among these county-level administrative districts, Dujiangyan City is a relatively special existence. Dujiangyan City is a typical city famous for a scenic spot, and the world-famous Dujiangyan Water Conservancy Project has brought great popularity to Dujiangyan City.
First, let's introduce the situation in Dujiangyan City. The mighty Min River forms a narrow river valley on the Western Sichuan Plateau, and the county seats of Mao County and Wenchuan County in Aba Prefecture are located in the Minjiang River Valley. After leaving Wenchuan County, the Min River continues to flow south, and after leaving the river valley, it enters the vast and fertile western boundary of the Sichuan Basin, which is Dujiangyan City, about sixty kilometers northwest of Chengdu. The former Shu Emperor Wang built Guanzhou, the prefecture was in the current Dujiangyan City, the Northern Song Dynasty set up a state-level Yongkang Army, the founding emperor of the Ming Dynasty Zhu Yuanzhang demoted the prefecture-level Guanzhou to a county-level Guanzhou. The name Guanxian was used until 1988, when it was officially renamed Dujiangyan City.
If you don't write about Dujiangyan City's most famous tourist attraction, the Dujiangyan Water Conservancy Project, it is equivalent to not looking at Wuyishan In Wuyishan City, Fujian Province, and not looking at Honghu Lake in Hubei Province. Dujiangyan Water Conservancy Project is the earliest water conservancy project in the world, and Dujiangyan is still benefiting the people, which can be called a miracle of miracles.
When it comes to why the ancients built Dujiangyan, there are many stories here. During the Warring States period, the qin monarch Qin Xiaogong reused the Wei state Gongsun Martingale (Shang martingale) transformation method, and the Qin state became stronger. Although King Huiwen of Qin killed Shang Martin because of his personal grudges, he continued to practice the law of Shang Martingale, and the Qin state became stronger. In 316 BC, the upper echelons of the Qin state held a meeting on how to expand outward. Zhang Yi suggested a crusade against Korea in the east, but the general Sima Que believed that the Shu state in the south should be cut down, on the grounds that the Shu land was fertile and the strength was not as good as Qin, and it could be easily taken. After consideration, King Huiwen of Qin decided to take Shu, and he quickly took it. The history books say very clearly, "Qin has gained Shu, and the Qin state is strong and strong, and can lighten the princes." "With the fertile Sichuan Basin as a rear supply base, the Qin state had enough capital to expand eastward.
However, problems also arise, which are related to minjiang. As mentioned earlier, the Min River flows from the Western Sichuan Plateau to the Sichuan Basin, and due to the difference in altitude, after leaving Dujiangyan City, the Min River has become a hanging river. How much is the altitude gap? It's scary to say, more than 270 meters! The Kaifeng section of the Yellow River is also a hanging river, but the gap is far less than that of the Dujiangyan city to Chengdu section of the Minjiang River. If the Min River, which has plenty of water, breaks its mouth near Dujiangyan City, Chengdu, which is not far away, will be greatly threatened by flooding. The problem of the Min River hanging in the air had always plagued the rulers of the Qin state, and King Zhaoxiang of Qin made a decision to send Li Bing to guard Shu County. There are several theories about the year in which Li Bing served as the shou of Shu County, one saying that it was 256 BC and the other said that it was 272 BC.
Li Bing knew very well that the burden on his shoulders was heavy, and if he could hold the Min River, then Shuzhong would be rich and the Qin state would benefit, which could help the Qin state to unify. If he could not complete his task, Min Jiang would turn Shuzhong into an unstable factor affecting the qin state's eastward expansion to unify the world, and the consequences would be unimaginable.
Regarding the details of how Li Bing built the Dujiangyan Water Conservancy Project, we do not need to talk about it. After Li Bing and his son (known as Li Erlang in the folk) came to Shuzhong, after field investigation, Li Bing determined the idea of controlling water: divide the Min River into two waters, and the water will lead straight to Chengdu. As a result, the possibility of flood disasters in the MinJiang River has decreased, and at the same time, it has become passive to active, and the water of the Minjiang River has provided impetus for the agricultural development of the Sichuan Basin. With the joint efforts of Li Bing's father and son and the local people, a few years later, the great Dujiangyan Water Conservancy Project became an eternal monument in history. By the way: one of the prototypes of the famous water-irrigation erlang god in folk mythology is the son of Li Bing.
The Qin Dynasty was soon abandoned by history, but the Dujiangyan Water Conservancy Project built by the Qin State still benefited the people of the Sichuan Basin during the Two Han Dynasties. Zhuge Liang called Sichuan the country of Tianfu in the "Longzhong Pair", the people of Yin and the country were rich, and Dujiangyan was indispensable. We all know that Zhuge Liang's success in governing Shu is extraordinary, in fact, Zhuge Liang's achievements in governing Dujiangyan are very prominent.
The Shu Han dynasty was the weakest of the three kingdoms, and the main grain producing area was only the Sichuan Basin, so the Dujiangyan water conservancy project would be decisive for the stability of the Shu Han Dynasty and the role of the Northern Expedition. A problem occurred in Dujiangyan, which was bound to affect the food supply of Shu Han, and before Cao Wei could attack, Shu Han himself would collapse from within. During Zhuge Liang's Northern Expedition, he once set up a weir official in Dujiangyan, and there were special people to guard Dujiangyan.
The Dujiangyan Water Conservancy Project has endured more than two thousand years of wind and rain and still plays a huge role, and we should thank all the ancient people who contributed to this.