Study suggests human interaction with the environment played a central role in the Western Han Dynasty's demise after five centuries in power

Levees set the stage for devastating flood that killed millions in 14-17 AD

This caused riverbed to rise making it more vulnerable to major flooding

For thousands of years, nature has been blamed for the deadly floods of China's Yellow River, long known in China as the ‘River of Sorrow’ and ‘Scourge of the Sons of Han.’

But according to a recent study, it was human activity rather than Mother Nature that began changing the river’s natural flow 3,000 years ago, leading to the death of millions.

The report provides the earliest known archaeological evidence of man-made, large-scale levees and other flood-control systems in the eastern region.

This maps shows historically identified courses of the Yellow River and its mega-deltas. According to a recent study by Washington University, it was human activity rather than Mother Nature that began changing the river’s natural flow 3,000 years ago, leading to the death of millions through flooding

It suggests the Chinese government’s long-running efforts to tame the Yellow River with levees, dikes and drainage ditches actually made flooding much worse.

This, they claim, set the stage for a catastrophic flood between 14-17 AD, which may have triggered the collapse of the Western Han Dynasty.

‘Human intervention in the Chinese environment is relatively massive, remarkably early and nowhere more keenly witnessed than in attempts to harness the Yellow River,’ said Dr Tristram Kidder from Washington University.

For thousands of years, the destructive force of nature has been blamed for the deadly floods of China's Yellow River, long known in China as the ‘River of Sorrow’ and ‘Scourge of the Sons of Han’

The southwest corner of the brick quarry dig site at Anshang shows remnants of the bank/levee in the sedimentary record. It shows a vicious cycle of primitive levees built larger and larger as erosion increased and periodic floods grew more widespread and destructive

THE DEMISE OF THE WESTERN HAN DYNASTY (202 BC – 220 AD) The Western Han was regarded as the first unified and powerful empire in Chinese history While there are many theories behind the fall of the Western Han Dynasty, Dr Kidder’s research suggests human interaction with the environment played a central role in its demise. A census taken by China in 2 AD suggests the area struck by the massive 14-17 AD flood was very heavily populated, with an average of 122 people per square kilometre, or approximately 9.5 million people living directly in the flood’s path. Historical accounts indicate that communities hit by the flood were soon in complete disarray, with reports of people resorting to banditry to obtain food and stay alive. By AD 20-21, the devastated region had become the centre of a rebellion that would end the Western Han Dynasty’s five-century reign of power. Advertisement

‘In some ways, these findings offer a new benchmark for the beginning of the Anthropocene, the epoch in which humans became the most dominant global force in nature.’

‘By 2,000 years ago, people were controlling the Yellow River, or at least thought they were controlling it, and that’s the problem.’

Dr Kidder’s research is based on a study of sedimentary soils deposited along the Yellow River over thousands of years.

It included data from the Sanyangzhuang site, known today as ‘China’s Pompeii,’ which was slowly buried beneath five metres of sediment during a massive flood in 14 to 17 AD.

It also looked at the Anshang site, discovered in 2012, includes the remains of a human-constructed levee and three irrigation/drainage ditches dating to the Zhou Dynasty from 1046–256 BC.

Researchers examined about 50 vertical feet of exposed soil layers at the Anshang site, cleaning sections of a quarry wall to reveal patterns of sedimentary deposits dating back about 10,000 years.

Boxed section of Image A shows the first stage of a bank/levee exposed in the excavation at Anshang. Image B offers a closer view of the boxed section showing mixed and loaded sediments near the base of the bank/levee

Nearly a third of this 10,000-year cross-section has been deposited in the last 2,000 years, indicating that the rate of deposit has steadily increased at a pace that mirrors the expansion of human activity in the region.

‘Our analysis clearly shows that these levees are not naturally formed berms, but are indeed artificially created through the work of humans,’ said Dr Kidder.

His research suggests the Chinese began building drainage canals and bank systems along the lower reaches of the Yellow River between 2,900 and 2,700 years ago.

The sedimentary record shows a vicious cycle of primitive levees built larger and larger as erosion increased, and periodic floods grew more widespread and destructive.

The Yellow River Vallley of China, with Box A identifying the flood plain regions researched in this study.The star in Box B is the location of the Anshang and Sanyangzhuang sites. The Loess Plateau is indicated by shading

While there are many theories behind the fall of the Western Han Dynasty, Dr Kidder’s research suggests human interaction with the environment played a central role in its demise. Pictured are Han dynasty laborers dressing clay statues of imperial army soldiers

‘It’s easy to see the trap they fell into,’ Dr Kidder said. ‘Building levees causes sediments to accumulate in the river bed, raising the river higher, and making it more vulnerable to flooding, which requires you to build the levee higher, which causes the sediments to accumulate, and the process repeats itself.’

While there are many theories behind the fall of the Western Han Dynasty, Dr Kidder’s research suggests human interaction with the environment played a central role in its demise.

A census taken by China in 2 AD suggests the area struck by the massive 14 to 17 AD flood was very heavily populated, with an average of 122 people per square kilometre, or approximately 9.5 million people living directly in the flood’s path.

Historical accounts indicate that communities hit by the flood were soon in complete disarray, with reports of people resorting to banditry to obtain food and stay alive.

By 20 to 21 AD, the devastated region had become the centre of a rebellion that would end the Western Han Dynasty’s five-century reign of power.

‘The big issue here is that human beings clearly changed the environment, and that these changes had real consequences for human history,’ Dr Kidder said.