A great flood at the dawn of Chinese civilization was said to have swept away settlements, the water rising so high that it overran heaven itself. It was the sage King Yu who tamed the waters by building ditches, the legend went, thus earning a mandate to rule and laying the foundation for China's first dynasty, the Xia. But until now, scientists could not pin down evidence that the flood, or Yu, or even the Xia dynasty ever existed. Now a team of researchers led by Wu Qianlong, a former Peking University seismologist, says it has indeed found evidence that a flood submerged a vast swath of the country almost 4,000 years ago, possibly lending weight to a long-standing—though controversial—theory that the Xia dynasty did exist as China's first unified state, reports the AP.
Using radiocarbon dating of bones and soil along the Yellow River, Wu's team established that an earthquake triggered a huge landslide, damming the waterway in 1920BC. The researchers deduced that for six to nine months, about 4 trillion gallons of water (about half the size of Lake Mead) built up behind a wall of rock and dirt near Jishi Gorge in today's Qinghai province. When the dam broke, it tore through the gorge and submerged the North China Plain, which is considered the cradle of Chinese civilization. The flood would have predated the first written records; historical texts from about 1000BC first mentioned a legendary Xia ruler, Yu—said to have been based around Jishi Gorge—who had devised a system of dredges to control a great flood that spanned generations.