How does Jiangyan water conservancy project achieve a high degree of harmony and unity between man and nature?

It was an ancient large-scale water conservancy project built by Li Bing in Qin and Shu counties around 256 BC, using the principle of fluid mechanics and adopting the form of dam-free water diversion buildings. Dujiangyan chose the intersection of the Minjiang Pass with unique natural conditions and the top of Chengdu Fan Plain as the weir site, and cut the remaining vein of Leiyushan, which extends to the center of Tongjiang, to form a firm and controllable bottle mouth water intake. Make a fishmouth diversion dike in the middle of Minjiang River bend to divide water and sand; A spillway with flying sand weir is built between Yuzui diversion dike and Baokou water intake, which can automatically discharge flood and sediment. Dujiangyan No.3 has scientifically planned, rationally laid out and skillfully cooperated in the main project, and jointly played the functions of water diversion, water diversion, backwater, water diversion and flood discharge and sediment discharge, forming a scientific and complete engineering system with free control. Since Dujiangyan was founded, the "Four Six" water transfer has been basically realized, and 60% of the water is discharged from the outer river, which not only ensures the water demand in Neijiang irrigation area, but also prevents disasters. Dujiangyan Water Conservancy Project has created a form of water conservancy in which man and nature coexist harmoniously, which directly affects the vast areas of China. This kind of engineering form shows the idea of conforming to nature and protecting nature in ancient water conservancy planning, and is praised as "pro-nature water conservancy project" by foreign environmental and water conservancy experts. Dujiangyan not only has the function of irrigation and drainage, but also has a waterway, which brings many benefits to water supply, waterway transportation, environmental protection and flood control in Chengdu and surrounding towns. It has also spawned a variety of cultural phenomena and become a "living water conservancy museum" in China and even the world. In the long-term operation and maintenance management, we have summed up "three-character classics", "six-character formula" (deep scouring beach, low weir-) and "eight-character motto" (make the best use of the situation and adapt it to the times; The experience of water control, such as cutting corners and worrying about the right direction, has been passed down from generation to generation, constantly practiced and enriched, and has made outstanding contributions to the development of water science theory. Traditional engineering technologies such as "Cage Stone Project", "Tuncha Project", "Dry Gravel Project", "Pile-driven sheepfold Project" and "Riverside Project" created by Dujiangyan in the long-term treatment practice are based on local materials, and the construction is simple, economical and effective. This not only ensures the effective governance of Dujiangyan, but also plays a great role in the governance of the Yellow River basin, the Yangtze River basin and the Pearl River basin in China. It is a treasure in the treasure house of water conservancy science in China and even in the world. It is unique in the history of water conservancy science and technology in the world and provides a unique witness for the ancient water conservancy civilization that has disappeared. Dujiangyan has created a rich and prosperous "land of abundance", which has made great contributions to the United development of the Chinese nation, disaster relief in past dynasties, victory over foreign aggression, and modern civilization in Chengdu Plain today, and has had a far-reaching impact in China and the world. On October 29th, 2000/kloc-0, 165438 was included in the World Cultural Heritage List at the 24th United Nations World Heritage Committee held in Cairns, Australia.