What is the specific function and long-term significance of Dujiangyan?

The concrete function and long-term significance of Dujiangyan lies in:

Scientific and technological value? Very reasonable planning and site selection. Dujiangyan headwork project is located at the mouth of Minjiang River, where the topography suddenly changed from alpine valley to plain, and the riverbed of Minjiang River suddenly opened, and the water potential slowed down. Just at the top of the fan-shaped Chengdu plain, 739 meters above sea level, it is the commanding height of the whole Dujiangyan irrigation area. The good geographical position enables Dujiangyan to control the water potential of Minjiang River in the canyon.

Setting the canal head hub is the best location, so that it can not be directly discharged into Chengdu plain, but also control the irrigation of Dujiangyan irrigation area because of its high terrain.

Clever engineering layout. The three main projects make full use of the surrounding topographic environment and the water flow law of bend circulation in Minjiang River bed, and play a leading role in the whole canal head project, successfully completing the tasks of water diversion, flood discharge and sediment discharge, making Dujiangyan a world-famous dam-free water diversion hub. Fish mouth divides Minjiang River into Neijiang River and Waijiang River, and automatically adjusts the diversion ratio of Neijiang River and Waijiang River according to the incoming water from the upper reaches of Minjiang River. This is the magical effect of Dujiangyan's "dividing 46 rivers to prevent drought".

The joint action of the bottle mouth and the flying sand weir ensures the water diversion of Neijiang.

Control the amount of water entering the Chengdu Plain, so that excess flood and sand are discharged into the outer river.

It has played the role of flood control barrier and diversion throat in Dujiangyan irrigation area. ?

Traditional hydraulic technology with distinctive features and unique advantages. In the history of Dujiangyan water control, the industrious and intelligent Shu people used bamboo, wood and pebbles as the main materials to create four traditional water conservancy technologies with Dujiangyan characteristics-bamboo cage, rafter, sheepfold and dry paving pebbles.

Dujiangyan traditional water conservancy technology has the advantages of local materials, low cost, simple technology and recycling, and is widely used in water conservancy construction practices such as intercepting water diversion, building dikes and revetment, and emergency blocking, which has played an important role in Dujiangyan's long-term stability. ?

Advanced management system. Dujiangyan has set up specialized institutions since the Three Kingdoms period, and at the same time, the government has formed hierarchical management, with water users participating in management.

Management system. Provincial management agencies are responsible for the management of Dujiangyan headwaters and main canals, local governments are responsible for the management of local branch canals, and irrigation users below branch canals are autonomous. Water right and maintenance responsibility of upstream and downstream administrative areas in irrigation area

Any system such as water fee collection, water distribution and labor organization for beneficiary users is guaranteed.

In addition, the annual maintenance system, which began in the Song Dynasty and continues to this day, has played an important role in the long-term stability and sustainable development of Dujiangyan. ?

Dujiangyan is a highly integrated and mutually beneficial ecological project. The construction of Dujiangyan made full use of the surrounding topography, either built along the river or split the mountain to open water channels, which made Dujiangyan highly unified with the surrounding geographical environment and formed a seamless engineering system. Here, the boundary between engineering and environment can hardly be found.

Historical value? Dujiangyan has a long history and a large historical span. Dujiangyan was founded in Zhao Haoqi Xiang period of Qin Dynasty, which lasted for more than ten dynasties. Every dynasty endowed Dujiangyan with distinctive characteristics of the times and enriched its historical connotation. For example, the powerful national strength of the Tang Dynasty promoted the rapid development of Dujiangyan, and the Song Dynasty attached importance to the supervision, assessment and annual maintenance management of Dujiangyan, and the technological innovation of Dujiangyan weir in the Yuan and Ming Dynasties. ?

There are a vast number of documents and classics recording Dujiangyan, and the historical witness is very rich. Dujiangyan was first described by Sima Qian in Historical Records and Hequ since the Western Han Dynasty.

After that, the Customs of Yi Tong in the Eastern Han Dynasty, Huayang National Records in the Eastern Jin Dynasty and historical books of various dynasties emerged one after another. In addition, Dujiangyan is recorded in many geographical records such as Zhu. There are numerous travel notes, history and notes about Dujiangyan, which provide rich information for the world to study Dujiangyan.

The historical significance of sustainable development. At the same time as Dujiangyan, the Hanrabi Canal in Babylon, Cuba and the artificial canal in ancient Rome have long been abandoned, but Dujiangyan is unique, not only in use today, but also developing in scale and efficiency. Although some ancient water conservancy projects contemporary with Dujiangyan in China are still in use today, their scale and benefits cannot be compared with Dujiangyan.

Cultural Value Dujiangyan has nurtured a rich and colorful water culture with Dujiangyan characteristics, including literature, legends, religion, architecture, folk customs and so on, which has had an important impact on Sichuan Province and even China.

Worship of water god and its religious influence. Legends of Minjiang River, such as enlightened water control, Li rhinoceros fighting the river god, Li Erlang subduing the dragon, Wang Niangtan, spread in Sichuan, and entrusted the Sichuan people with their deep gratitude and infinite admiration for the heroes of water control in previous dynasties. Li Bing, the founder of Dujiangyan, was deified by local Taoism, and Li Bing and his son became important Taoist gods respected by local Taoism in Dujiangyan.

Dujiangyan is also an important birthplace of Jiro, an important deity in Taoism and folklore in China. In history, temples commemorating Li Bing were all over Sichuan, and all previous dynasties attached great importance to them.

In memory of Li Bing. ?

Poetry and other literary and artistic works. Many scholars and celebrities in history have left literary works about Dujiangyan, among which Du Fu, Lu You, Cen Can, Fan Chengda and Li Diaoyuan are all famous. In addition, there are countless inscriptions, inscriptions, folk songs and classics about Dujiangyan. ?

Rich irrigation culture. After Dujiangyan is restored every winter, Tomb-Sweeping Day holds a grand ceremony at the head of the canal, which is called "Boiling Water Festival" or "Water Festival". ?

Remarkable flood control benefits of heritage benefits. Before Dujiangyan was built, Chengdu Plain suffered from floods and droughts. "At the beginning of the river, Shu people were fish." After Li Bing built Dujiangyan, the problems of water diversion, flood discharge and sediment discharge were properly solved. In particular, Baokou, whose width has remained unchanged for thousands of years, has become the key to contain the flood in Minjiang River. Since then, there have been few global floods in Chengdu Plain. Therefore, Du Fu praised "Shu people boast for a thousand years, and the flood is not close to Zhangyilou". ?

The greater the irrigation efficiency. The combination of stable water source, superior gravity irrigation mode and high-quality soil in Chengdu Plain has made the agricultural production in Chengdu Plain develop rapidly and become a world-famous huge granary in a short time. "Drought and flood depend on people, there is no famine, and the world is rich." Due to the unique geographical advantages and the period of agricultural civilization, all dynasties attached great importance to agriculture.

Dujiangyan irrigation area has been opening up new irrigation areas, and the irrigation area along the north and south wings has been expanding, reaching more than 2.8 million mu during the Republic of China.

Because Dujiangyan irrigation has created a prosperous and rich "land of abundance", Chengdu Plain has become an important grain producing area and an important land of wealth, which has always been highly valued by the central government. ?

In peacetime, Dujiangyan Irrigation District supported the state power together with Jiangsu and Zhejiang with its rich tax revenue output. During the war, Sichuan became the refuge of the Central Plains civilization and a strategic place for revival, which influenced the historical trend of China at several critical moments. For example, at the end of Qin dynasty, "Yizhou is in danger, fertile land is thousands of miles away, and Gaozu is the emperor because of it."

During the Three Kingdoms period, Liu Bei established the Shu-Han regime for 44 years, relying on Shu. Chengdu has become the capital of the separatist regime five times before and after. Dujiangyan irrigation area has maintained the prosperity of Sichuan and contributed to the stability of the central government.

During the Anshi Rebellion in history, Emperor Xuanzong of the Tang Dynasty took refuge in Chengdu. Huang Chao, in exile in Shu. Until the 20th century, War of Resistance against Japanese Aggression and Sichuan were both important anti-Japanese rear areas. ?

Comprehensive water supply benefit. In addition to irrigation, Dujiangyan provides a rich and stable water flow for Chengdu Plain. The newly opened "Second River" connects the Minjiang River system with the Yangtze River waterway, making Chengdu an important water transportation hub. With goods all over the world and ships all over the world, Jinjiang has become the starting point of the Southern Silk Road.

Good ecological benefits. The completion of Dujiangyan has fundamentally improved the urban and rural ecological environment in Chengdu Plain. Since the Tang Dynasty, the developed urban water system in Chengdu consists of Mahachi River, Jinshui River, Yu He River, Fuhe River, Modi River and Qingshui River.