Water: The Elixir of Life

What does your new book, Elixir, cover?

My remit was for a history of the changing human relationship with water since the beginning of farming up to the Industrial Revolution. This was the moment, starting about 250 years ago, when we began deep pumping of water, and many of the rules changed.

What are the general themes of the book?

There are three themes. The first is gravity — water flows downhill, from a higher point to a lower one. The second is the close relationship in many human societies between ritual and water, well documented from many periods of history. The third is technology versus sustainability — our ability to live within our hydrological means.

Why do you think of the history of water in broad stages?

I argue that we have gone through three loosely defined “ages” of our relationship with water. The first is the longest and oldest, and persists in some places into modern times — the notion that water is scarce and something to treat with reverence.

The second stage began in some places about 2,000 years ago, when societies like the Romans began to treat water as a mere commodity. Today, we live in a third stage, where we are finally realizing that water is a finite resource, something precious to be conserved. Indeed, our survival depends on conservation.

When did people first manage water supplies?

For hundreds of thousands of years, people lived with water supplies by coming to them, something the Australian Aborigines do to this day. Hunting societies are mobile, whereas farmers tend to be sedentary, to live in one place for long periods of time.

This was when farming communities began to move water from streams, rivers and lakes, to their fields, using simple narrow furrows and dams to trap water from sudden rainstorms. Furrow irrigation began in Jordan at least 10,000 years ago.

Is furrow irrigation effective?

It’s extremely effective for small-scale subsistence farming. In fact, there are people in Kenya, like the Marakwet and Pokot, who still use furrows to bring water from rivers down to their fields. Their agriculture is basically self-sustaining, the maintenance and decisions about water allocation being made by family, kin groups and communities.

When did larger-scale irrigation first begin?

In Mesopotamia and Egypt at least 5,000 years ago. The original irrigation systems, even those used by cities, were based on village field systems, with control of water allocation belonging at the village level. The city rulers were interested in taxing yield, not details of farming.

This was relatively simple irrigation agriculture. When did irrigation begin on a much larger scale?

Contrary to popular belief, most Ancient Egyptian irrigation agriculture was very simple for at least 2,000 years, based on simple gravity canals and the annual Nile flood. The Assyrians of northern Mesopotamia were probably the first large-scale irrigators, who developed water works on a large scale using prisoners of war and slaves during the first millennium B.C.

Later irrigation works in Iraq were also on a large, impersonal scale, which led to widespread problems with salinization.

You write about qanats. What exactly are they?

Qanats were among the most significant inventions of ancient hydrologists. They are basically a way of tapping ground water by tunneling into the delta fans of streams, then allowing the ground water to flow down slope to irrigation fields where the water emerges above ground.

Qanats are dangerous to build but were extremely effective, some of them extending over several kilometers. As late as the 1950s, much of Tehran’s water supplies came from qanats. These ingenious devices spread widely through the Mediterranean world into North Africa, Yemen and Spain. A version of them based on the same principle is found in southern Peruvian desert.

You devote considerable space to Asian water management and an entire chapter to the Chinese. What was different in these parts of the world?

Indian water engineers, like those in Sri Lanka, were maestros of reservoirs and water storage, using wells and reservoirs in such ancient cities as Harappa in Pakistan. The Buddhist city of Anuradhapura in Sri Lanka boasted of enormous reservoirs that irrigated large tracts of land.

Chinese water engineers often thought on a large scale, as did the Khmer rulers, who lived in great enters set in huge seasonally flooded landscapes surrounded by reservoirs. The Chinese emperors often deployed 1,000 workers at a time to build canals in the drought stricken Yellow River valley of the north, but almost invariably without success.

Even today, the Chinese think of water management on a large scale with their ambitious schemes for north/south canals to bring water from the tropical south to the arid north. The ecological consequences of these great schemes have not really been thought through.

What about aqueducts? Weren’t they important for the Greeks and Romans?

Aqueducts began at least as early as the Assyrians, but it was the Greeks who first built them on a large scale for cities like Athens and Syracuse. In fact, they were among the best of all ancient water engineers.

The Romans were great copiers and adopted aqueducts on a large scale, often carrying water long distances not only for domestic supplies but mainly to supply public baths. Such facilities were important centers for commercial, political and social affairs. Even the wastewater was used to wash out the public toilets set nearby.

Aqueducts flowed permanently, which led, inevitably, to an assumption that water was a readily available commodity to which people were entitled. Our sense of entitlement to cheap water goes back at least to the Romans.

You describe Islamic water engineers as among history’s best. Why?

They inherited thousands of years of expertise at water management in arid and semi-arid lands and then adapted it to different regions of their empire. There was nothing that Islamic farmers did not know about extracting water from such environments and, of course, Islamic gardens like those at Granada in Spain are famous — symbolic representations of paradise.

What about the Maya and Inca?

They were just as expert as people in the Old World, if sometimes even more so. I describe how the Ancient Maya conserved water and distributed it, using their great pyramids as water catchments.

Perhaps the most adept of all were the Inca of the Andes in South America, who were blessed with an abundance of water. Recent hydrological research has puzzled out the details of how they used gravity to provide water at such places as Machu Picchu high in the mountains.

How did the Industrial Revolution change everything?

The term “revolution” is misleading, as the technological developments behind it came to pass over several centuries. In the end, both steam power, then fossil fuels produced technologies that could pump water supplies from very deep below the earth which hitherto had been inaccessible to water wheels and other technologies.

The long-term consequences have been disastrous, for we are depleting aquifers and ground water in many parts of the world with promiscuous abandon.

The longer-term future for rising global populations, insatiable demand for more food, and huge cities is downright scary — as many authors have laid out. The promiscuous pumping of deep water has changed all the dynamics of water and our relationships with it.

What’s the big lesson from history?

That we need to treat the world’s finite water supplies — and they are indeed finite — with deep respect. And in the long term, for all our vaunted technologies, many of the solutions and pathways to sustainability lie in making conservation an integral part of everyone’s lives. And that is very hard to achieve.

What do you hope Elixir will achieve?

I’ve tried to write a definitive history of human relationships with water that will be around for a while, as a source of information and encouragement. Judging from initial feedback, it’s achieving that goal. In many ways, it’s the culmination of over ten years of writing books about ancient climate change and human societies of all kinds.

And finally, what’s your next book?

On a very different subject. Beyond the Blue Horizon looks at ways in which people have decoded the mysteries of the world’s oceans. Not galleons and warships, but traditional craft and ancient ways of finding one’s way across the ocean. Again, it’s a book with a lot of ritual in it and is also based on my personal experience as a small boat sailor. It has turned out to be a fascinating subject and is due to come out in mid-2012.