China Hydraulic Engineering - Yellow River And The Grand Canal

I am reading Philip Ball's excellent book The Water Kingdom: A Secret History Of China. It describes the epic problems of river flow management that China has grappled with over millennia. Enormous floods have always ravaged China. At the site of a large dam at Sanmenxia on the Yellow River is an inscription in honor of the Great Yu ( ~ 2200- 2100 B.C), who as the story goes,  conquered a flood. The inscription says " When the Yellow River is at Peace, the Nation is at Peace". Flood control required enormous civic resources and cooperation and the ability to tame river waters gave political and moral legitimacy to the ruling class.The taming of nature using cooperative people power and as a sign of a strong united society has deep roots in Chinese political thinking.

One particular vexing problem was the very high rates of silt load carried by the Yellow River. A vast area of the Yellow River watershed drains the Loess deposits of north central China. This is a plateau made up of loose friable sand and silt blown in from the Gobi desert of Mongolia. Erosion of Loess fills the river with sediment. There is 300 grams of sediment for every kilogram of Yellow River water giving the river a reddish golden color. Erosion has carved the Loess Plateau in to a landscape of ravines and gorges. The American journalist Edgar Snow in the 1930's described it thus:

" an infinite variety of queer, embattled shapes - hills, like great castles, like ranges torn by some giant hand, leaving  behind the imprint of angry fingers. Fantastic, incredible and sometimes frightening shapes, a world configurated by a mad God - and sometimes a world of strange surrealist beauty. "

High rates of sedimentation meant that the Yellow River bed could aggrade or rise, increasing the risk of the river breaking its banks and flooding the countryside. Dyke building to constraint the river channel began as early as the seventh century B.C. by the state of Qi.

Constant dredging of the Yellow River and the associated tributaries and canal systems ( the Grand Canal) was also required to maintain a channel deep enough for navigation to move armies and grains from south to north.  River channel and canal maintenance acquired a new urgency when Zhu Di known as the Yongle Emperor of the Ming dynasty moved the capital north from Nanjing in the eastern province of Jiansu to Beijing in the early 1400's. The rational was probably to keep the political center closer to the armies amassed on the northern frontier where the Ming faced a threat from the Mongol and Manchurian steppe people. Later in the 1600's, the Manchurians overthrew the Ming and established the Qing Dynasty. Although over time, the Qing assimilated into the larger Han cultural milieu, they felt more at home in the north of the country. That meant the Yellow River and the Grand Canal system had to kept in top navigable order.

Desperation to unclog  the river channel spurred technological innovation. 

An extract:

Removing silt from the Yellow River demanded some impressive technology, not to mention serious organization. The Song government set up a Yellow River Dredging Commission in 1073 which began to deploy boats equipped with dredging tools. The vividly named  "iron dragon-claw silt dispersing machine" was a great rake pulled along the riverbed to agitate the silt and return it to the flow. This principle was extended with the 'river-deepening harrow', a 2.5 metre-long rotating beam fitted with iron spikes, like a thresher for riverine mud. The Ming imperial censor Chen Bangke introduced new techniques in the late sixteenth century, such as wooden machines set rolling and vibrating by the current to constantly stir up the sediment. In the dry season Chen proposed simply digging out the silt manually.

The Ming official Pan Jixun in 1565 or so came up with a solution that has made him one of China's water heroes. He pointed out that if one confines the water flow to a narrow channel, it will have enough strength to scour the sediment off the river bed. There would be minimal need for laborious manual dredging. He may have borrowed the  idea from a Confucian text of the Han era (~200 B.C - 220 A.D) called Zhou li (Rites of Zhou) which stated "A good canal is scoured by its own water". 

Chinese philosophical tradition impacted river management strategies. Daoists argued that the river be given room to spread and build wide floodplains in concert with the principle of wu wei which could be read to mean "do nothing" or "having a yielding attitude".  Confucians on the other hand wanted the river to be managed by human  engineering and recommended the construction of high dykes to keep the river channel narrow and constrained.

Joseph Needham, the noted historian of China writes that 'during twenty centuries the two schools contented'.. 'and neither proved wholly successful'.

Highly Recommended.

Books: Origins Of Complexity ; China Water History

These just arrived.

Extract:

I hope to persuade you that energy is central to evolution, that we can only understand the properties of life if we bring energy into the equation..... I want to show you that the origin of life was driven by energy flux, that proton gradients were central to the emergence of cells, and that their use constrained the structure of both bacteria and archaea. I want to demonstrate that these constraints dominated the later evolution of cells, keeping the bacteria and archaea forever simple in morphology, despite their biochemical virtuosity. I want to prove that a rare event, an endosymbiosis in which one bacterium got inside an archaeon, broke those constraints, enabling the evolution of vastly more complex cells. .....Finally, I want to convince you that thinking in these energetic terms allows us to predict aspects of our own biology, notably a deep evolutionary trade-off between fertility and fitness in youth, on the one hand, and ageing and disease on the other.

The last book I read on the evolution of complexity was Mark Ridley's The Cooperative Gene which described the many evolutionary inventions that suppress genomic conflict and make multicellular bodies workable. Nike Lane writes at a more fundamental level of the energy currency of the cell. Feeling very excited about this book. I am sure to learn a lot.

Extract:

But the ubiquitous and ambivalent relationship that the Chinese people have had with water has made it a powerful and versatile metaphor for philosophical thought and artistic expression, and its political connotations can be subverted and manipulated in subtle ways for the purposes and protest and dissent. These meanings of water are more than metaphorical. Because the lives of everyday folk has always depended on water, the river and canals mediate their relationship to the state. Water -too much of it,or too little - has incited the people to rise up and overthrow their governments and emperors. Burgeoning economic growth now places unprecedented pressure on the integrity and sometimes the very existence of China's waterways and lakes. Not only can China's leaders ill afford to ignore this potential brake on economic growth, but the environmental problems are leading to more political pluralism in a nominally one party state.

Sweeping... from the Qin Dynasty (200 B.C.) to the present..

Early Chinese History Told Through Maps And Poetry

I am really enjoying Jerry Brotton's A History Of The World In 12 Maps. One richly rewarding chapter is on early Chinese map making traditions and inevitably you end up learning quite a bit of history as well.

The Song dynasty (907- 1276 AD) struggled with keeping the empire unified and intact and faced particularly strong challenges from the Jurchen Jin a confederacy of Tungusic tribes from northern Manchuria. In the middle of the 12th century the Song were forced to sign a peace treaty with the Jurchen Jin ceding to them nearly half their northern territory.

Subsequent imperial maps drawn up by the Song never showed this division. Rather, an idealized geography that the Song kept dreaming of based on earlier classical texts like Yu Gong, that of a unified empire to which foreign barbarian rulers paid tribute was portrayed. Using maps as a tool for political propaganda is an old trick! 

What maps did not depict though, poetic license did.

This beautiful passage from the book:

Poetry describing maps either side of the traumatic division of the Song also captures their power to first acknowledge, and then lament the loss of territory. Writing more than 100 years earlier, the ninth century Tang poet Cao Song describes 'Examining " The Map of Chinese and Non Chinese Territories"':

With a touch of the brush the earth can be shrunk;
Unrolling the map I encounter peace.

The Chinese occupy a prominent position;
Under what constellation do we find the border areas!

On this occasion the almost meditative act of unrolling the map and seeing a unified Chinese dynasty at its center evokes emotions of security and assurance. Later Southern Song poets used a similar conceit, but with very different emotions. Writing in the late twelfth century, the celebrated Lu You (1125-1210) lamented:

I have been around for seventy years, but my heart has 
remained as it was in the beginning, 
Unintentionally I spread the map, and tears come gushing forth.

The map is now an emotive sign of loss and grief, and perhaps a 'template for action', a call to unite what has been lost.

A Warning From A Chinese Thomas Malthus

My Book Shelf # 23

In 1793 Hong Liangji, a bureaucrat in the Qing empire had an idea. He had been sent as an education inspector to Guizhou Province in the southwestern part of China. The arrival of crops from  the Americas like maize, potato and sweet potato, capable of thriving in marginal soils and steeper slopes, meant that more areas were coming under the plough and China was experiencing a population boom.

Hong Liangji worked out the consequences for a 8 person family:

Eight people would require the help of hired servants, there would be, say, ten people in the household. With the ten-room house and the 100 mu of farmland,  I believe they would have just enough space to live in and food to eat, although barely enough. In time, however, there will be grandsons, who, in turn, will marry. The aged members of the household will pass away, but there could still be more than twenty people in the family. With more than twenty  people sharing a house and working 100 mu of farmland, I am sure that even if they eat very frugally and live in crowded quarters, their needs will not be met. 

Hong conceded that the Qing had opened up new land to support China's population. But the amount of farmland had 

only doubled or , at the most, increased three to five times, while the population has grown ten to twenty times. Thus farmland and houses are always in short supply, while there is always a surplus of households and population... Question: Do Heaven-and-earth have a way of dealing with this situation? Answer: Heaven-and-earth's way of making adjustments lies in flood, drought, and plagues. 

Hong had described the Malthusian trap 5 years before the idea came to Thomas Malthus. He not only predicted that standards of living will stagnate as population increase outstrips resources but that there will be ecological consequences of the relentless drive to deforest and reshape the landscape for growing more and more food.

From 1493: Uncovering The New World Columbus Created  - Charles Mann.