Scientific study of China’s great flood could prove 4,000-year-old legend
Researchers find evidence of truth behind legend, with findings that could trim centuries off founding date of first dynasty
Many people died some 4,000 years ago when a major earthquake jolted Jishi Gorge, a deep, rocky Yellow River valley in what is now Qinghai province.
But aside from the immediate death toll, centred in the Guanting Basin several kilometres downstream, with some people buried at the entrances to collapsed cave dwellings as they tried to flee, it was a prelude to an even greater catastrophe – China’s great flood.
One landslide trigged by the earthquake plunged into the Yellow River, forming a 200 metre high dam, higher than today’s Three Gorges Dam on the Yangtze. It completely blocked the flow of China’s second-largest river and in the following six to nine months up to 12 billion to 17 billion cubic metres of water built up behind the dam.
It then collapsed, sending a torrent of water 500 times the average natural flow through Jishi Gorge hurtling more than 2,000km downstream. It “ranks globally among the largest freshwater floods of the Holocene”, according to a research paper published in the latest issue of Science magazine on Friday.
For the first time, science has provided evidence for China’s great flood, as important a part of Chinese legend as the biblical story of Noah is in the West.
“The timing, the location, the magnitude ... all matched well to the legend that had been passed down for thousands of years,” Dr Wu Qinglong, the lead researcher of the study, said in an exclusive interview with the South China Morning Post on Tuesday. “Strong geological and archaeological evidence has brought the descriptions in ancient Chinese texts to life.”
The legend of Yu versus the Great Flood holds a deeply rooted, important place in Chinese culture and indeed the genesis of the Chinese nation. According to the legend, the great flood occurred in the period of the Three Sage Kings, forcing the survivors to abandon farmlands on lower ground for shelter in the mountains, which were then covered by thick forest and home to wild beasts. Yao, the first ruler, appointed Shun to deal with the forest and Gun to deal with the flood.
Shun set the forest on fire, which not only reduced the vegetation but killed most of the animals, thus giving the human race more living space. Gun tried to contain the flood with man-made banks but failed. Yao passed the throne to Shun because of his success, and Shun killed Gun before appointing Gun’s son Yu to carry on with his father’s unfinished job.
Yu used a different method, dredging the Yellow River so the excess water could flow freely in designated courses. He worked hard, wearing all the hair off his lower legs as he spent most of the time with labourers, and did not return home to see his family for more than a decade. Following his success in the battle against the great flood, Yu took the throne from Shun and established Xia, the first dynasty in Chinese history, by passing power to his son instead of his most meritorious subordinate, setting a precedent for later dynasties.
The great flood legend features in many ancient historical documents. The idea that only a powerful, centralised government led by a wise leader with the spirit of self-sacrifice could save the nation spurred the development of the Confucian school of thought, which dominated Chinese government for millennia.
However, the actual existence of the great flood had long remained a subject of conjecture. In the absence of evidence of flooding as widespread and long-lasting as that mentioned in the ancient texts – according to the book Shiji (Records of the Grand Historian) by the Han dynasty historian Sima Qian the waters took 22 years to subside – most people nowadays regard it as a fairytale.
Now it turns out those ancient descriptions of the great flood were firmly grounded in reality, according to an international team of scientists led by Wu who spent the past decade studying the catastrophic Yellow River flood, believed to have occurred in 1920BC.
They say the torrent of water, equivalent to a third of the Three Gorges Dam reservoir, would have breached natural levees on downstream plains and caused secondary flooding in the following decades. The catastrophe “would have survived in the collective memories of these societies for generations, eventually becoming formalised in the received accounts of the great flood in the first millennium BCE”, the authors added.
In recent years, there has been speculation that the great flood mentioned in ancient Chinese texts was caused by climate change, but more recent studies have found that the climate at the time was cooler and drier than today due to a weaker East Asian monsoon.
The new study by Wu and his team says evidence discovered in Lajia, the archaeological site of a prehistoric village in the Guanting Basin, points to a powerful earthquake as the precursor event. Many of the remains found at Lajia were contorted in pain at the time of death, while many artefacts such as pots were found in their original locations in the cave dwellings, suggesting a sudden, catastrophic earthquake was to blame.
Carbon dating of the bones of three children found at the Lajia site suggested they died around 1920BC, said Wu, who conducted the research at Peking University, Nanjing Normal University and the China Earthquake Administration’s Institute of Geology.
The size of the lake formed behind the landslide was calculated by geological survey of the remains of the landslide in Jishi Gorge, jishi meaning “piled-up rocks” in Chinese. “First something as big as a small hill fell into the gorge, and when it collapsed the water was emptied in a day, creating a flood that has never been seen again in Chinese history,” Wu said.
According to the new study, the Xia dynasty would have been founded around 1900BC, two to three centuries later than previous estimates. Xia has often been regarded as the beginning of Chinese history, which could thus be shorter than previously thought, according to the paper .
The study involved many researchers from different disciplines, including archaeologists, geologists and chronologists, from institutes in mainland China, Taiwan and the United States.
A co-author of the paper, Professor Ye Maolin from the Chinese Academy of Social Sciences’ Institute of Archaeology, said Wu spent nearly a decade on the project with very little funding, and he hoped that more resources would be made available in the future to investigate the topic because some important problems remained unsolved
The scale of the earthquake, for instance, remained unclear, he said, although some researchers suggested it may have fallen between magnitude seven and eight on the Richter scale.
And researchers had made other important discoveries at the Lajia site, such as the world’s earliest noodles, Ye said, which hinted at a sophisticated civilization and called for further study.
There’s even a debate about whether Yu could really have tamed the great flood. Some researchers argued that ancient society, with primitive tools and technology, would have stood helpless in the face of such a big disaster and that the water level would have dropped due to reduced rainfall, caused by climate change, not human dredging.
“The great flood not only appeared in ancient Chinese texts but also in other civilizations,” Ye said. “Studying the issue will not only help us better understand where we come from, but what may be awaiting ahead.”