Did humans cause the great flooding of China's Yellow River? 3,000-year-old levees accidentally led to millions of deaths
- Chinese built canals and banks along Yellow River around 2,900 years ago
- Sedimentary record shows a vicious cycle of levees built larger and larger
- Building large levees caused sediments to accumulate on the river bed
- This caused riverbed to rise making it more vulnerable to major flooding
- Levees set the stage for devastating flood that killed millions in 14-17 AD
- Study suggests human interaction with the environment played a central role in the Western Han Dynasty's demise after five centuries in power
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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
‘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.
‘It happened in the past and can happen again.’
Read more: http://www.dailymail.co.uk/sciencetech/article-2665889
英國《每日郵報》星期二（2014.6月24日）報道了美國華盛頓大學科學家獲得最新考古研究成果的消息，這項研究涉及中國古代漢朝治理黃河的工程。
科學家在研究中考察了過去數千年黃河流域的土壤沉積，考察地點包括在公元14年到17年間由於巨大的洪水而被緩慢埋在5米沉積物下的三楊莊遺址。
三楊莊位於河南省黃河故道，被形容為「中國的龐貝」。
報道說，華盛頓大學科學家的這份報告提供了人類在東方地區大規模建造水壩和排水系統的最早的考古學證據。
但是報告認為，中國政府試圖以水壩和排水渠治理黃河的長期努力並沒有奏效，反而使洪災更為嚴重。
報告說，這樣的工程導致了公元14年到17年間的洪水大爆發，造成數百萬人死亡，而且很可能促成了西漢王朝的滅亡。
研究發現，中國人大約在2900年前或2700年前就在黃河下游修建水壩和排水系統。
惡性循環
參加這項研究的基德爾博士（Dr Tristram Kidder）指出，人類對中國環境的干預相對規模較大、時間較早，而最多的干預表現在對黃河的控制方面。
基德爾博士說，修建水壩導致沉積物在河牀蓄積，抬高了河流的高度，增加了爆發洪水的危險，從而需要修建更高的大壩，這會造成更多的沉積，導致惡性循環。
研究認為，有關西漢王朝的滅亡有很多不同的理論，但人類對環境的干預是重要因素之一。
報告說，中國在公元2年進行的人口調查顯示，公元14年至17年洪水襲擊區域人口密集，達到每平方公里122人。也就是說，有大約950萬人居住在直接遭受洪水襲擊的水道上。
據史料記載，洪水造成嚴重混亂。到公元20年至21年間，洪災區成為反叛活動的中心，這促成了漢王朝的滅亡。
基德爾博士說，一個嚴重的問題是，人類改變了環境，造成了嚴重的後果。這樣的事情過去發生過，今後還會發生。
（編譯：躍生/責編：董樂）
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