As the local governor of the Shu prefecture, Li Bing commissioned a hydraulic survey (this was in the 3rd century BC while most of Europe was living in straw huts). One of the key elements was that although the site was nearly perfect, it needed a canal at a critical point and there was a ridge in the way. Li Bing's solution was to cut a channel through the end of the ridge to allow the water through into the plain in a controlled manner. Without the benefit of explosives, the channel through the ridge was cut using freeze-thaw techniques of heating up rocks and then pouring cold water on them to shatter the rock face. The system worked and after eight years and the use of hundreds of thousands of men, the Baopingkou (Bottlneck Gate) was cut.
To create the dyke in the middle, rocks were placed in bamboo baskets and later on, soil and earth was used to bolster it. This technique is still used today for protecting embankments and spillways. The Yuzui dyke was completed in four years. The whole project took 14 years, and the rsults changed a nation; the canals into Chengdu became navigable and trade was stimulated across the whole plain.
Despite the research giving more credit to other, earlier surveyors and engineers, there have been archaeological discoveries recently that again suggest that Li Bing was the master planner. A statue of Li Bing dating to 168BC wa discovered, as were water level gauges. However, there has been widespread suspiscion of the timing of the discovery of the gauges as they came - miraculously - just before the local auhtorities announced that the new dam upstream would - yep, you've guessed it - lower the water levels at Dujiangyan. What a coincidence!!
There is still much controversy over the history of Dujiangyan, exacerbated by political propaganda connected to the construction of new dams in the area. The story is not quite as clear as the guidebooks suggest.
The history of the Dujiangyan rests on two historical accounts, the "Historical Records" and the "History of the Han Dynasty", but also on a lesser-known book "The Annals of the Huayang Kingdom" which is known to be somewhat biased. Through history in many societies, including present-day China, history is presented from the perspective of the victors.
Now the Dujiangyan works were an immensely significant milestone in early Chinese history, not because of the works themselves but because they created a new, stable agricultural heartland which sucked in a hundred thousand immigrants, rapidly leading to a powerful economy that eventually enabled the formation and war successes of the Qin Dynasty. The role of Li Bing may have been deliberately overplayed in order to further enhance the reputation of the country's rulers at the time.
The official line remains attractive, even if some research has suggested that others played a major role and that some key elements (like how the Baopingkou was formed) may have been created naturally.
All has not been well at Dujiangyu during the last decade, as a huge dam (the Zipingpu dam: 150m high wall, the height of a 50 storey skyscraper) has been constructed nearby upstream of Dujiangyan. In addition, a further dam was proposed actually at Dujiangyan (the Yangliuhu Dam).
Fortunately, the plan for the Yangliuhu Dam has now been shelved (Temporarily? Who knows?), but the saga is a fascinating account of how environmental and cultural heritage issues still clash in China.
See the report in the China Heritage Newsletter.
The Dujiangyan Irrigation Works appeal, as a day tour, to giant pandas as well.
On July 15th 2005, a 4 year old female giant panda turned up in the centre of Dujiangyan. Local men saw the pandas shadow at night and thought it was a large dog, but in the morning footprints were seen that clearly were those of a panda. Shortly afterwards, the panda was seen swimming in a local river. Although swimming comfortably, she was clearly distressed and after climbing out she evaded attempts to catch her, before being knocked out by a tranquiliser dart while resting in a tree. (Note that, in common with many of these stories in China, the various news reports are difficult to work out exactly and are all garbled about where exactly the panda was found or when or by whom...there are various 'editions' of the report!)
She was taken to the Wolong Reserve where she recovered. I understand that she was released later.
It is claimed locally, supported by the evidence of the panda visitor last year, that there are pandas in the Qingchengshan to the southwest of Dujiangyan city.
Favorite thing: Near the dujiangyan dam, you can find some shops selling various kinds of souvenirs like the one in the photograph. Some of the very cheap items include the Chinese flute which the shop owner is blowing.