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Dragons and Magical Dirt: Legendary 'Great Flood' Left Real Evidence
The Guanting Basin would have been under water the height of one-third the Empire State Building during China's "Great Flood."
Credit: Wu Qinglong

With the help of a channel-digging dragon and magical, water-absorbing dirt, the legendary Emperor Yu is said to have saved China from a Great Flood that lasted thousands of years. While this tale is the stuff of myths, with plenty of embellishments added through the years, geologists are finding that at least part of the story is based in reality.

The ancient Chinese legend holds that a devastating flood of the Yellow River forced people from their homes and washed away farmland, leading to famine. Emperor Yu is said to have tamed the floodwaters by dredging the river bed. The heroic emperor went on to establish the Xia Dynasty, the first in Chinese history.

Until now, a lack of geological evidence for such a flood left some scholars questioning whether the legend tells the story of a real disaster or if it was propaganda used to justify imperial rule. [Top 10 Deadliest Natural Disasters in History]

Now, a team of scientists has provided geological evidence for a disastrous flood that occurred around 1920 B.C., which could be the origin of the legend. The research, published today (Aug. 4) in the journal Science, reconstructed ancient events along the Yellow River — including an earthquake, a landslide and a dam burst — that led to a catastrophic flood.

If this ancient flood is in fact what came to be known as the Great Flood, then Emperor Yu's Xia Dynasty likely started several centuries later than historians had thought, the researchers said.

"Because this flood happens at a critical turning point in the development of Chinese civilization, this geological event takes on even greater significance," said study co-author David Cohen, an archaeologist at the National Taiwan University. "This is because the flood dates to the likely time period for China's legendary Great Flood, and this is the first time a flood of the scale large enough to account for it has been found."

The study shows that an enormous flood surged down the Yellow River after a dam broke. In their research along the Yellow River, in China's Qinghai province, the scientists found remains of a landslide, dam and outburst flood sediments downstream that allowed them to reconstruct the flood's size.

"The flood was about 300,000 to 500,000 cubic meters per second [about 10,600,000 to 17,650,000 cubic feet per second]. To put that into perspective, that's roughly equivalent to the largest flood ever measured on the Amazon River, the world's largest river," said study author Darryl Granger, a geologist at Purdue University in West Lafayette, Indiana. "It's more than 500 times larger than a flood we might expect on the Yellow River from a massive rainfall event."

The researchers were able to determine the flood year by dating human remains from people who died in the same earthquake that triggered the landslide that dammed the river. Granger said the remains of children, because they grow so quickly, their bones give an accurate and reliable age at the time of their death. This allowed the researchers to narrow the time frame in which the flood would have occurred.

Given the timing of this flooding event, plus information from historical texts and astronomical evidence, the researchers said the Xia Dynasty likely began around 1900 B.C., with Emperor Yu starting his reign in 1914 B.C.

Much of Chinese dynastic history is dated as a "floating chronology," Cohen said. Evidence drawn from ancient documents has allowed historians to determine the duration and order of the reigns, but not necessarily specific years. Especially in the case of the Xia Dynasty, which was originally thought to have begun in 2070 B.C., the historiographic evidence was lacking, he said.

Cohen explained that the basic calculations for each reign was based on a "leapfrogging" approach, the historians would move backward from a known point to determine each predecessor's reign.

"There has to be an anchor point somewhere in that," Cohen said.

This flood, if it is indeed the legendary "Great Flood," could be the Xia Dynasty's anchor point, the researchers said. Beyond supporting the legend of Emperor Yu's flood, the new research could offer researchers a greater understanding of China's ancient history, they said.

Original article on Live Science.