Steven Solomon
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Irrigation farming societies also developed in other hydrological habitats based upon staple crops other than field agriculture of wheat and related grains. By the third millennium BC transplanted rice was being extensively cultivated in paddies along the naturally flooded fields of the monsoonal river valleys of Southeast Asia. This garden cultivation, too, required sophisticated, labor-intensive water management—storing the downpour, transplanting rice plants, and submerging and draining paddies at just the right levels and seasons, for instance, to support much more densely populated, civilized communities. Yet the monsoon-fed wet rice garden cultivation was not done on a scale as grand or politically centralized as in the semiarid wheat field agriculture, river-irrigation states. The seasonal rains delivered sufficient natural water supplies to support independent, smaller communities that did not need, and indeed could better resist, any centralized government command. In fact, the case of early wet rice societies supported the general observation that the way water resources presented themselves exerted a strong influence on the nature of the society’s political system. By and large, where wealth-creating water resources were widely and easily accessible and not dominated by the existence of an arterial transport and irrigating waterway, there was a stronger tendency for smaller, more-decentralized, and less-authoritarian regimes to prevail.
The spread of civilization to cropland watered only by rainfall about a thousand years after the rise of large-scale irrigation societies represented one of history’s most enduring, if slow-moving, expansive forces. In wheat-growing regions, the key development was the diffusion of the animal-powered wooden traction plow that facilitated the cultivation of large enough tracks to sustain fixed village communities. Yet nowhere did rain-fed farming ever produce the food surpluses, population densities, grand civilizations, and empires supported by irrigation; their heyday on the world stage, rather, depended upon the advent of other, later technological developments. Thus, for nearly all of history when wealth came from agriculture, one of the central dividing lines of human civilization lay between water-rich, irrigated agrarian states and water-challenged, sparsely populated, relatively poor, small, rain-fed farming communities.
Two other historical dividing lines were also marked by water usage. One was the gradual emergence of seafaring civilizations on the fringes of antiquity’s irrigation empires in lands with marginal domestic agricultural fertility that earned their wealth principally by trading among neighboring states. Sea trade, which exploited the fast and cheap navigation potential of water’s buoyancy, advanced in the Mediterranean Sea with the development of sail and oar-powered wooden cargo ships suitable for its relatively calm, enclosed waters and evolved very gradually into a significant historical force by the second millennium BC. In the Mediterranean, the Red Sea, and the Indian Ocean, sea traders facilitated cross-cultural and commercial exchange based upon market-set prices that over many centuries helped propagate a small but vibrant unregulated economic sphere in which the early beginnings of the modern market economy were nurtured.
The other great water demarcation line was the barbarian divide—the existential clash of societal organization and lifestyles between the nomadic pastoralist descendants of primitive hunter-gatherers and the expanding, civilized agricultural realm. The militarily skillful barbarian tribes of the central Asian steppes, the desert Bedouins of the Arabian Peninsula, and later the Nordic Vikings in their river longboats were far fewer in number and ranged Earth’s more water-fragile and less-yielding landscapes, herding their animals between water holes, and trading with or, when strong enough, raiding or demanding tribute from civilized settlements. Periodically, they gathered enough strength under great warrior leaders to lead fearsome invasions that disrupted, overwhelmed, and ultimately reinvigorated civilized empires across the world. History recorded four great barbarian waves, starting with the Bronze Age charioteers of 1700–1400 BC and ending with the Turkish-Mongol invasions from the 700s through the fourteenth century, when the age of gunpowder and sheer manpower advantages decided matters for settled civilization. The slow, fitful expansion of civilized society around the globe was always synchronized with the breakthroughs and setbacks in irrigated and rain-fed cultivation, some of which were landmark events of world history. Wherever farming took hold, population advanced. In 8000 BC the planet was populated by about 4 million hunter-gatherers. After 5000 BC it began to double every 1,000 years. By 1000 BC world population had reached about 50 million. Then, under the prosperous shield of order-providing empires, it generally accelerated. By the late second century AD, some 200 million people inhabited the world. Even Watt’s steam engine and the Industrial Revolution did not lessen civilization’s reliance on agriculture. Instead, they provided new tools to enhance innovation production to feed the growing demand of a world inhabited by 6.5 billion by the early twenty-first century. Despite the dramatic expansion of total cropland, water volumes, and agricultural technologies, one thing that has not changed since ancient times is man’s greater reliance on irrigation to feed himself. Today, two-fifths of the world’s food is being grown on less than one-fifth of the planet’s irrigated, arable land. All of human society today shares an irrigation legacy with the cradle civilizations of antiquity.
CHAPTER THREE
Rivers, Irrigation, and the Earliest Empires
One of the striking common features of ancient history was that all of mankind’s four great cradle civilizations were wheat, barley, or millet field irrigation agricultural societies that arose in semiarid environments alongside large, flooding, and navigable rivers. For all their differences, Egypt around the Nile, Mesopotamia along the twin Tigris and Euphrates, the Indus civilization around the Indus, and China along the middle reaches of the Yellow River also shared similar political economic characteristics. They were hierarchical, centralized, authoritarian states ruled by hereditary despots claiming godly kinship or mandate in alliance with an elite class of priests and bureaucrats. All power was imposed top-down through control of water, which was the paramount factor of economic production, and managed through the marshaling of mass labor.
In his classic 1957 work, Oriental Despotism, Karl A. Wittfogel proposed a causal linkage between centralized authoritarian states and specialized, mass irrigation agriculture. The overriding challenge of so-called hydraulic society, he posited, was how to intensify exploitation of its silt-spreading, flooding river’s potential water resources. The larger the river, the greater was the potential productive wealth, population density, and power of the ruling hydraulic state. Yet only centralized planning and authoritarian organization on an immense scale could exploit water resources to their productive maximum. Surplus yields depended critically upon delivery of adequate supplies of water at the right time to the right places as well as protection against catastrophic flooding. This required the forced, often brutal mobilization of hundreds of thousands, and sometimes millions, of peasant laborers during lulls in the farming season to construct and maintain irrigation and diversionary canals, sluices, water storage dams, protective dikes and levees, and other waterworks.
The bulky, inherently hard-to-manage physical property of liquid water itself, noted Wittfogel, “creates a technical task which is solved either by mass labor or not at all.” Once conscripted and organized for waterworks, the workforces were readily mobilized by the state to construct its other celebrated grand monuments of hydraulic civilizations—pyramids, temples, palaces, elaborate walled cities, and other defensive fortifications like China’s Great Wall. In further support of his hydraulic theory, Wittfogel observed that similarly organized theocratic, authoritarian, gigantic public-works-building agrarian societies, based on miraculously easy and fast-growing maize and potatoes, and responding to other labor-intensive water management challenges, were reinvented again much later in the New World, among the Olmec-Maya on cultivated swamp mounds of the tropical lowland habitats of Central America and on the bleak, terraced, and irrigation-channeled mountain plat
eaus of the Andes inhabited by the Incas and their predecessors.
Wittfogel’s theory of hydraulic society fueled much debate over the decades, including whether the cooperative needs of irrigation created the large centralized state or vice versa. Yet such debate often sailed past the most salient point: the two social formations were complementary; they reinforced one another. Power and social organization in such societies depended absolutely upon regimented, concentrated control of the water supply. Whenever the water flow was interrupted, whether from natural or political causes, crop production fell, surpluses dissipated, dynasties and empires toppled, and starvation and anarchy threatened the entire social order. Ancient hydraulic societies tended to thrive where two prominent conditions existed: first and foremost, where the best available resources of water were highly concentrated in the state-controlled irrigation source; second, where the unifying presence of a dominating, navigable river gave the state command over regional communication, commerce, political administration, and military deployment.
For millennia authoritarian irrigation societies produced the most advanced civilizations in the world. Although the hydraulic model would be supplemented, and eventually superseded, by new social formations, it produced a recognizable prototype that has endured through history. Whatever the era, huge water projects requiring vast mobilization of resources tended to go hand in hand with large, centralized state activity. Vestiges of this hydraulic tendency were evident in the giant dams built in the twentieth century by centralizing liberal democratic, communist, and totalitarian states, often in the early stages of restoration periods.
Ancient Egypt was the prototype hydraulic civilization because its river, the Nile, was the consummate hydraulic waterway. The Greek historian Herodotus, who visited in 460 BC, famously described Egypt as the “Gift of the Nile.” Indeed, Egypt’s history was—and still is—almost entirely determined by what happened on and around the natural phenomena of its great river.
The Nile provided everything that was needed in virtually rainless Egypt. It was the only large source of irrigation water and its annual flood brought a thick, self-renewing layer of fertile black silt for its farmland. Unlike other great rivers, the annual flood season arrived and receded with clockwork predictability and in miraculous synchronization with the agricultural cycle of planting and harvesting. It was one of the easiest landscapes to manage for irrigation. Egyptian farmers needed merely to construct embankment breeches, sluice gates, extension channels, and some simple dikes to retain sufficient floodwater to soak the soil in the cultivated, low-lying basins beyond the river before releasing the excess to the next basin downstream. The Nile’s steep gradient, furthermore, kept the river flowing steadily with good drainage that helped to flush out the soil-poisoning salts that afflicted artificial irrigation systems everywhere else. Indeed, the Nile was world history’s only self-sustaining, major river irrigation system.
The Nile’s natural beneficence also bestowed Egypt with a second great gift—it was a rare two-way navigable river. Its current and surface wind moved in opposite directions all year round, so it was possible to float downriver with the current and sail south upriver in simple, broad-bottomed vessels with square sails.
Finally, the wide, waterless desert beyond both banks provided a defensive barrier that helped insulate ancient Egyptian civilization against large-scale invasion for centuries. As a result of Egypt’s total reliance on its single grand river, the flow of political power to the center in Egypt was simple, total, and unchanging. Throughout history, whoever controlled the Nile also controlled Egypt.
The Nile’s bounty, however, depended upon one unpredictable variable beyond the Pharaoh’s control—the extent of the river’s annual flood. Excessive flooding inundated entire villages and wiped away cropland. Far worse were years of low flooding when insufficient water and silt resulted in famine, desperation, and chaos. To an astonishing degree, dynastic rises and declines throughout Egypt’s long history correlated to cyclic variations in the Nile’s floods. Good flood periods produced food surpluses, political unity between Upper Egypt’s Nile Valley and Lower Egypt’s marshy delta, waterworks expansions, Egyptian civilization’s glorious temples and monuments, and dynastic restorations. Extended years of low flood, by contrast, were dark ages of privation, disunity, and dynastic collapses. Without Nile water, neither the wise nor the corrupt could rule effectively. Pharaoh’s kingdom fractured between valley and delta and sometimes further into competing precincts ruled by warlords and menaced by bandits.
Ancient Egypt was marked by the rise of three great kingdoms—the Old Kingdom (circa 3150–2200 BC), the Middle Kingdom (2040–1674 BC) and the New Kingdom (1552–1069 BC)—and their respective dissolutions into the intervening First, Second, and Third Intermediate Periods. Nile flood levels were so important to determining tax revenue from the harvest and overall governance that they were assiduously monitored by priestly technocrats from Egypt’s early beginnings by nilometers, which were depth gauges marked off on stones and originally situated at temples along the river. Nilometer records show that the fates of Egypt’s subsequent occupiers were likewise driven by cyclic oscillations in the flood level of the Nile. In short, the rhythms of the Nile framed all the essential parameters of history and life in Egypt, including food production, population size, extent of dynastic reach, and conditions of peace or strife.
Nile flood levels, in turn, ultimately depended upon an occurrence far beyond Egypt’s borders—the degree of the summer monsoonal rains that fell at the headwaters of the Blue Nile. The Blue Nile started in Ethiopia’s Abyssinian plateau at over 6,000 feet at a spring venerated by the modern Ethiopian Orthodox Church. The southernmost source of the White Nile, the river’s other main branch, was at a spring in Burundi in Africa’s equatorial plateau lake region. The Blue and White Niles came together just north of Khartoum in the Nubian Desert before entering Egypt. By the time the Nile emptied into the Mediterranean Sea, its 4,168-mile journey made it the world’s longest river. Yet by total water volume it was comparatively small—only 2 percent of the mighty Amazon, 12 percent of the Congo, 15 percent of the Yangtze, 30 percent of the Mississippi and 70 percent of Europe’s Danube, Pakistan’s Indus, or America’s Columbia rivers. Virtually none of its net flow originated within rainless Egypt’s own hot, arid borders. Since about half the White Nile’s water evaporated in Sudan before reaching Egypt, some four-fifths of the river flow sustaining Egyptian civilization, and nearly all its precious silt, originated in the highlands and deep ravines of Ethiopia.
Every summer monsoonal rains swelled the Nile’s tributaries in Ethiopia, triggering the downstream rush and the annual flood. The river normally rose in northern Sudan by May and by June reached the first cataract near Aswan in southern Egypt. By September the entire Egyptian Nile Valley floodplain was inundated under a turbid, reddish-brown lake, which then began to recede into the main river channel but left behind its thick, odorous residue of fertile black silt. By managing the overflow of water with simple irrigation works, Egyptian farmers produced the ancient Mediterranean’s richest breadbasket. Crops were planted in the waterlogged soil following the inundation and harvested in late April and May after the floods were gone; during the early summer the mud baked and cracked under the hot sun, aerating and reinvigorating the soil. Seeds were cast over the ground and buried by wooden scratch plows—a simple hoelike, wheelless implement dragged by a draft animal. Thousands of years of annual flood deposit built up 10-foot-high natural embankments ideal for human settlements on both sides of the river’s nearly 600-mile length through the narrow Nile Valley. Just over the embankments were low-lying basins for farming, a total area less than modern Switzerland, into which farmers channeled the Nile’s resources of water and silt to produce Egypt’s emmer wheat and barley.
Ancient Egypt & Nile
The Nile in Egypt consisted of two distinct hydrological and political zones. Upper Egypt was the Nile Valley from the first cataract at A
swan. Just north of modern Cairo began the fan-shaped, rich, labyrinthine 100-mile-long delta of reedy marshes and lagoons of Lower Egypt, whose topography and history were also partly molded by the fluctuating sea levels of the Mediterranean. When the kingdom was robust, one Pharaoh wore the double red and white crown symbolizing the unity of delta and valley, respectively.