Dujiangyan
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| UNESCO World Heritage Site | |
|---|---|
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| Criteria | Cultural: ii, iv, vi |
| Reference | 1001 |
| Inscription | 2000 (24th Session) |
| Coordinates | 31°0′6.012″N 103°36′19.008″E / 31.00167000°N 103.60528000°E |
Dujiangyan (Chinese: 都江堰; pinyin: Dūjiāngyàn) is an irrigation infra-structure built in 256 BC during the Warring States Period of China by the Kingdom of Qin. It is located in the Min River (岷江, Mǐn jiāng) in Sichuan Province, China near the capital Chengdu (成都, Chéngdu). It is still in use today and still irrigates over 5,300 square kilometers of land in the region.
Before Construction
Prior to its construction devastating annual floods plagued the people living by the Min River. Qin official Li Bing (李冰，lǐ bīng), who was sent to Chengdu as its magistrate, decided to do something about this. He investigated the river with some locals, and familiarizing himself with the land forms and water flows, found the source of the water. He discovered that the waters melted from Mount Min at the beginning of each summer, flowing into the Min River and eventually flooding the farms.
Plan for a Dam
Li Bing decided to divide the river into two streams, allowing one stream to continue on its normal course, while the other stream would flow into the farmer's fields. But there was one big problem. The Yulei 'Mountain' (a rocky hill) blocked the way to the Chengdu Plain. He had to break a path through the hill. The rock was too hard to break. So he had men throw wood and grass on the rocks and set it on fire, and then pour cold water over it. This made the hard rock crack so the men could remove it. This labor took 7 years and they finally made an opening through the hill to the plains that is 20 meters (65 feet) wide. The peasants called it 宝瓶口, bǎo píng kǒu (Bottleneck).
Problems Encountered
Li Bing split the river into two parts, but the part that was suppose to flow into the fields was higher than the other side, so very little water went there. He changed his plan a bit. He decided to build a man-made island levee to separate the two parts and force more water to go into the Bottleneck.
Building a man-made island in the middle of the river also proved difficult. Li Bing tried to construct the base using pebbles and clay, but the water washed them away. He tried using huge boulders, but when the floods came, even these were scattered. To solve this problem, he had men construct huge bamboo cages, each several dozen meters long, and placed boulders inside them. He made hundreds of these, and dropped them in the middle of the river. According to legend, Li Beng came upon this idea after seeing women put bamboo cages containing clothes waiting to be washed in a fast-moving stream.
With this solid foundation, Li Beng was able to construct a large island. In order to reduce turbulent flow and follow the shape of the existing river, he made the island curved. The island was connected by a bridge to the Yulei "Mountain".
Results of Construction
After the system was finished, no more floods occurred. The irrigation made Sichuan the most productive agricultural place in China. Li Bing was loved so much that he became a god to the people there. On the east side of Dujiangyan, people built a shrine in remembrance of Li Bing.
Dujiangyan Today
Today, Dujiangyan has become a major tourist attraction. It is also the admiration of scientists around the world, because it has one ingenious feature. Unlike contemporary dams where the water is blocked with a huge wall, Dujiangyan still lets water go through naturally. Modern dams do not let fish go through very well, since each dam is a wall and the water levels are different. In 2000, Dujiangyan became a UNESCO World Heritage Site.
See also
- Karez well system
- Chengdu
- Li Bing
- Mekong
- Warring States Period
- Sichuan
- State of Qin
- UNESCO World Heritage Sites
External links
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