unlike the mythical Emperor Yao, Li Bing’s existence is well documented. His most extraordinary accomplishment was the building of the first dam, which still functions in modernized form. At a place called Dujiangyan, he divided the Minjiang River, a tributary of the Yangtze. The diverted water goes into a series of spillways and channels that can be opened to irrigate in times of droughts and closed in times of flooding. He had three stone figures of men placed in the water as gauges. If their feet were visible, this signaled drought conditions and the dam’s gates were opened to let in water.
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