How did China's 'Stone Age Venice' fall?

The city of Luong Chu with a complex water canal system that existed more than 5,000 years ago may perish due to climate change.

The city of Liangzhou in the Yangtze River Delta, China, achieved remarkable technical progress 5,300 years ago and may have been the only city in the world to do so at that time. The complex system of canals and dams gives the city the name of China's "Stone Age Venice". However, nearly 1,000 years later, the city and civilization of Luong Chu suddenly collapsed, the cause of which is still controversial.

Shennong Cave in the Yangtze Valley helps reveal the fate of Liang Chu, one of the greatest cities of ancient times. (Photo: Haiwei Zhang)

Professor Christoph Spotl at the University of Innsbruck and colleagues suggest that it is possible that temporary climate changes cause floods so severe that even such advanced water canal systems cannot withstand. 11 news. The new study is published in the journal Science Advances.

At a time when most of the world had not yet discovered agriculture, Luong Chu pioneered hydraulic engineering. The city was walled to keep out invaders, but the real highlight was the network of water channels that helped the inhabitants cultivate large swaths of the fertile but naturally flooded plains.

It was a miracle that people who had not yet discovered metallurgy built such an ancient wonder. However, Spotl was more interested in why such a long-standing city would collapse. He and his colleagues related the time of collapse to changes in the severity of the rainy season.

"A thin layer of clay was found in the ruins. This indicates that the demise of this advanced civilization may have been related to floods originating in the Yangtze River or the East China Sea. No no trace of human-caused causes like conflict or war," Spotl said.

To test whether flooding was the cause, the team of experts studied the climate in the Yangtze River valley over the past 100,000 years using stalagmites in Shennong and Cuu Long caves. The rate of limestone precipitation in these caves gives little information about the rainfall of that period, while carbon isotope analysis gives more accuracy.

About 4,345 - 4,324 years ago, the valley experienced a significant increase in rainfall. This timing coincides with the demise of Luong Chu, taking into account the study's margin of error.

"Heavy rains during the rainy season can lead to severe flooding of the Yangtze River and its tributaries. The disaster is so severe that even the complex system of canals and dams cannot withstand such huge volumes of water. So, the city of Luong Chu was destroyed and the people had to evacuate," Spotl explained.

If things return to normal quickly, perhaps the survivor will return to the city. However, traces in the caves show that heavy rains continued for the next 300 years. The rains can be so frequent that at that time the city cannot recover. By the time the climate returns to Luong Chu's heyday, the city is nothing more than a legend with the descendants of the inhabitants who once lived there.