Researchers in China found first evidence for the legendary catastrophic Great Flood that occurred on the Yellow River, an event that resulted in emergence of the first ruling Xia dynasty of China. Folk tales and written records mention the hero Yu who fought the floodwaters about 4000 years ago, which earned him the mandate to establish the dynasty marking the beginning of the Chinese civilization.

Chinese researchers of the Peking University and Nanjing Normal University reconstructed the sequence of events that led to the flood through mapping of distinctive sediments along the Yellow River in Qinghai Province.  The series of events leading up to the flood is said to begin an earthquake which destroyed the Lajia site, a settlement of the Qijia culture. Cave dwellings at Lajia collapsed, killing all the people there. The earthquake triggered a massive rock slide that dammed the river and backed up a lake that was at least 200 meters deep. Within six to nine months, the lake overflowed and the landslide dam failed catastrophically, sweeping over the Lajia site. The flood is said to have the flow of 300-500000 cubic meters per second. Radiocarbon techniques used on samples from the site helped to date the earthquake and flood to around 1920 BC. The date of the flood, coincides also with the transition from Neolithic to Bronze Age in the Yellow River valley and with the beginning of the Erlitou culture that dominated China in the early Bronze Age.

The researchers determined the dimension of the flood channel and exactly how high the flood waters reached. Among the documented evidence are remains of a landslide dam, dammed lake sediments upstream, and outburst flood sediments found downstream. The dam deposits reach an elevation of 240 metres above the present river level and stretch for more than 1280 metres along Jishi Gorge.

(after CBC News & Seeker)