II. The Dawn of Irrigation in the Middle East
III. Cement Rivers
IV. Farm Codes & Hillside Qanat
V. But Where On Earth Did Water Come from?
VI. Rock Me Mama Like a Water Wheel
VII. Aqua Vitae: Water of Life
VIII. Westward Ho, the Bandwagons!
IX. Soviet Surface Water Misfires
X. A Gee-Ode of Global Groundwater
XI. A Bridge Past Troubled Water to the Future
XII. Further Reading
The same year that the Atlanta Braves won the World Series with virtually no hitting, a web-toed Kevin Costner urinated into a cup, poured the contents into a Rube Goldberg machine of tubes and demijohns, and drank the resulting potion. Critics were not impressed. Had she been born at the time of this film’s release, McKayla would not have been, either.
Roger Ebert gave the film featuring a gilled Kevin Costner 2.5 out of 4 stars. Waterworld, as the producers so imaginatively named the film, told of a dystopic future -- probably around 500 years distant -- in which the world was entirely covered by water. The polar ice caps had melted, and gangs of terrible actors roamed the planet. But an equally chilling and pressing water-related issue has emerged since Waterworld’s box office debut: many of Earth’s largest reservoirs of freshwater are dropping.
In fourth grade, if you had a particularly captivating teacher and weren’t busy picking broccoli from your braces, you may have learned that the Earth consists of approximately 70% water. Of this, less than 3% is freshwater fit for drinking. And of this 3%, the vast majority is locked up in the polar ice caps, the melting of which unleashed roving bands of Dennis Hoppers in Waterworld. The remaining freshwater must cater to the drinking demands of the Earth’s many animals, the cleaning demands of human buttocks, and the irrigation demands of human mouths.
Replenishing the aquifers that power our civilization is not an easy, quick-fix. It requires strategic, long-term planning, conscious consumption, and clever technology if we’re to hydrate the planet’s billions. In this chapter of Age of Ecology, we’ll explore the human relationship with water from antiquity to modern-day. Along the way, we’ll visit the fields of ancient Mesopotamia, marvel at ingenious devices from 3,000 years ago still in use today, and discuss the mysterious collapse of a number of civilizations over the eons. Last but not least, we’ll investigate some movements and technologies helping us to stave off the civilizational shambles that attend hydration fragmentation. Many of them come with the added benefit of helping us mitigate the climate change that has accompanied our polluting tendencies.
The English poet Samuel Taylor Coleridge was right to express superstitions after his famous mariner killed a helpful albatross. But with a healthy sense of urgency and a renewed reverence for Earth’s ecology, we can stave off the non-potable scenario sensationalized by Coleridge and Costner alike.
II. The Dawn of Irrigation in the Middle East
We begin our journey in the once-fertile plains of Mesopotamia, between the Tigris & Euphrates rivers. Three thousand years before the they invented cuneiform, an ancient people known as the Sumerians began to dig trenches to divert flood waters originating from the Zagros Mountains to their crops in the flat basin surrounding modern-day Baghdad. These irrigated fields could grow more figs, more barley, more beans. Sumer’s population grew and eventually began to intermingle with the Akkadians from the west. So arose the short-lived Akkadian Empire.
But neither the Akkadians nor the Sumerians within the Empire had past experiences to guide their irrigation techniques; the canals they carved into the region’s fertile soil sported much run and little rise, allowing the salt-laden sediment awash in the Zagros floods to fall out of suspension season after season. Slowly, salts accumulated on these once-fertile plains like dandruff on a dark sweater. Not to mention, the farmers left their fields exposed between plantings, letting the sun bake the topsoil into dust that winds carried off, leaving behind only those very dandruffy salts.
Working in tandem like fossil fuel companies and their lobbyists today, less vegetation in the region encouraged less cloud formation and combined with a period known as the 4.2 kiloyear aridification event to wring out the area like a sponge. Agriculture and, by extension, the Empire’s citizens, suffered immensely. Less than 200 years after the Akkadians consolidated their power in the city of Akkad, set in the bullseye of modern-day Iraq, the city fell to a group of nomads from the mountains to the northwest. By then, the region was salinized, and desertified.
The same 4.2 kiloyear aridity event brought down the Liangzhu Culture in modern-day China’s lower Yangtze River area, along with the Old Empire in present-day Egypt, another civilization based on extensive irrigation, in this case, of the Nile River. Near La Mancha, Spain, ancient Chalcolithic peoples built forts known as motillas on top of hills with wells tapped into the Iberian Peninsula’s underground aquifers. The forts helped defend the population and their food sources from parched invaders -- intriguingly, not far from where our closest cousins, the Neanderthals, made their last stand at Gibraltar, thirty thousand years earlier, as we'll discuss in a future chapter, "The Case of Our Missing Cousins".
III. Cement Rivers
Winding our way around the Mediterranean crags and cliffs to the east, we find ourselves a hundred years distant from those Iberian motillas, observing the Romans tilling their own irrigation innovation into the meandering history of water management. Mixing water and volcanic ash from the port town of Pozzuoli, Romans found they could use the resulting paste, a form of hydraulic cement, as a binding agent. They began to use this cement with rocks to fashion vast concrete culverts which could transport water over much longer distances than the earthen Sumerian canals. The technology would form the basis of the famous Roman aqueducts that arch across much of Italy to this day.
Two thousand years hence, cement in an almost unchanged form would carry water through Burbank, Calabasas, and the rest of Los Angeles’ San Fernando Valley, providing the water necessary to fuel the area’s explosive growth beginning around the 1920s. In the process, the Los Angeles Aqueduct would virtually wipe out the entire Owens Valley economy at the foot of California’s Sierra Nevada Mountains. “The Valley”, as the now-irrigated San Fernando Valley came to be called, would go on to become the fountainhead of that great tributary of modern culture, pornography.
But in the interim, dozens of other irrigation innovations would come down the pike.
IV. Farm Codes and Hillside Qanats
Hammurabi -- he of Code of Hammurabi fame -- took a break from blinding his populace to create a system of water regulations that required farmers to maintain their irrigation canals. Perhaps surprisingly, abrogation of these strictures did not require one to surrender his life by dehydration, but rather to surrender corn.
An even more famous example of irrigation innovation in antiquity comes to us 1,200 years after Hammurabi, from the same city of Hammurabi’s indefinite repose, Babylon, a mere 60 or so miles from where the Akkadian Empire fell in 2,200 B.C. One of the Seven Wonders of the Ancient World, the Hanging Gardens of Babylon, date to around 600 B.C., grown by virtue of an intensive irrigation network throughout the city. The source of water for the the irrigation canals? The Euphrates River, one of the two rivers that bordered the Fertile Crescent we learned about in grade school. Eventually, the irrigation canals extended over 30 miles into the surrounding mountains to irrigate the almonds, figs, and pears that King Nebuchadnezzar’s personnel grew inside the city.
To the East at almost the same time as the Hanging Gardens of Babylon, engineers from the Persian Empire in modern-day Iran had devised an ingenious system to tap into underground water reservoirs. These qanats represent perhaps the world’s first wells, a technology we still rely on today to provide water to a number of homes, particularly in more rural areas across the world. The genius of qanats is hard to understate. Engineers drill a series of vertical shafts into a hillside that allow them to access the hillside’s interior. They then excavate a gently sloping tunnel that eventually terminates where the hillside itself ends at the edge of flatter areas of settlement. Finally, they drill a mother well and one last tunnel to connect the mother well to the existing hillside tunnel. In this way, the Persians could transport water from inhospitable uplands to inhabitable lowlands with minimal evaporation along the way.
Many of these qanats are still in use today, more than 2,500 years after sweat-browed Persians toiled them into existence. One such series of qanats has even risen to the status of an UNESCO World Heritage site: the Qanats of Gonabad. Not far from Iran’s eastern border with Afghanistan, the Qanats of Gonabad sprang up under the reign of Cyrus the Great, legendary for both his military conquests -- including the Babylonians and their Hanging Gardens -- and for his tolerance of the religions of his new subjects. Perhaps Cyrus the Great’s tolerance stemmed from his own experience with Persia’s diverse religious influences, including Anahita, a water and fertility goddess whose tributary may have been the Hindu goddess of music, arts, learning, and wisdom, Saraswati.
V. But Where on Earth Did Water Come from?
Although we may take it for granted, water is one of the most ancient molecules on Planet Earth. Scientists originally believed that the water we squirt at each other today was not here from day one, but rather arrived on the backs of comets like Bastian Balthazar on the back of Falkor. The reasoning went that water must have arrived long after Earth formed because, in its infancy, Earth resembled the interior of a Hot Pocket. Molten. Chaotic. Of indeterminate life-giving properties.
But recent research sheds new light on the topic. Scientists at the Woods Hole Oceanographic Institute in Massachusetts found that the oldest meteorites in the galaxy, which formed around the same time as the Sun, have a similar chemical makeup as rocks on Earth. These carbonaceous chondrite meteorites, as they’re known, are thus likely candidates for bringing the Earth its water right around the time the Earth formed, and may have furnished water to other planets in our solar system, as well.
But the butterfly effects of physics and its puckish counterpart, chemistry, would not be so kind to other celestial bodies, whose water, in varying combinations, is trapped under poisonous gases, under thick sheets of ice, or deep underground only to shoot into outer space as geysers; or has burned off, as with Venus. It seems appropriate, then, that many religions around the world came to cherish and worship water deities -- not just Anahita in Persia and India, but in civilizations as far-flung as Celtic Gaul in Western Europe and Incan South America. Without water, none of these civilizations would have had mouths to feed, much less anything with which to feed them.
VI. Rock Me Mama Like a Water Wheel
Anahita’s Persian disciples were just getting started with those ancient wells, qanats. Some argue they went on to invent the Persian Wheel, although others claim the inventor’s prize should go to Hellenistic Egypt or India, as strange as that sounds given the name of the contraption. Ah, the rarefied air of misnomer mountain. Regardless of the origin, the Persian Wheel provided another development in the ever-evolving enigma of efficient irrigation. A farmer squinting in the sun would yoke a draft animal to a wheel device, then prod the animal. The invoked cow, for example, would snort and begin walking, powering a wheel device that dipped buckets into a water source and emptied them into a sluice. The farmer would then point the sluice wherever the water was desired. Similar devices to capture or harness the power of water continued for the next thousand years, including Archimedes Screw and a more modern, water wheel from Syria.
In the last century B.C., Syrian-style water wheels rolled into Europe close on the heels of the rickety Roman chariots so loved by the corrupt, narcissistic Roman emperor, Nero. (The same Nero who, according to Pliny the Elder, instigated the Great Fire of Rome to clear room for his 100-foot effigy; that he played fiddle while Rome burned was Flavian propaganda.) The main text on Roman water wheels comes from Vitruvius, who noted in his 10-volume tome on Roman engineering that they were seldom used, perhaps owing to Rome’s abundant slave labor. Leonardo da Vinci himself later immortalized Vitruvius in his sketch on the perfect human proportions.
While some historians point to Rome’s reliance on slave labor rather than developing technology as a catalyst in Rome’s downfall, a mill near modern-day Arles, France suggests otherwise. Drive past ancient fields in the south of France fitted together like floorboards, you’ll come upon an eroded hill that once stationed a mill capable of feeding the area’s 12,000 or so residents. As water left the churning of one wheel, a sluice running with the grade of the hill carried the water to the next wheel, grinding flour all along. The crumbling concrete aqueduct that once fed the mill winds its way through those ancient fields like the spine of a desert grazer.
The technology of water mills spread slowly through Europe in the Dark Ages that unfurled after the demise of the Roman Empire. Artisans with calloused fingers and cold in their bones relied on these mills to saw wood, mill the barley and wheat that bakers fashioned into bread for the upper crust, and in the 1700s, weave the textiles that northern Europe became known for.
VII. Aqua Vitae: Water of Life
While engineers were pressing forward with innovations in agriculture, the supreme hedonists known as monks were experimenting with a wholly different water-processing system. Since the days of the Egyptian dynasties, pharaohs and laborers alike had enjoyed the benefits of alcoholic beverages. Egypt’s pyramid-laborers received on the order of four to five liters per day of a rudimentary beer called heqet. That’s roughly one gallon, or around 10 beers a day. But who’s counting. Surely not them, after finishing their day’s rations.
Like beer, wine is thousands of years old, possibly originating in modern-day Iran around the Zagros Mountains over 7,000 years ago. And, as with beer, many poets, historians, and rulers alike consumed the product of fermented grapes on a near-daily basis: everyone from King Midas to Alexander the Great.
But unlike wine and beer, distilled spirits had, even as recently as the 10th century, eluded capture. Although scientists in medieval China, Arabia, and Italy all seemed to discover the process of distillation independently in a form of parallel innovation, the record is rather quiet as to whether they applied the technology to fermented beverages to make liquor. Then, a little over 1,200 years ago, a man by the name of Abu Musa Jabir ibn Hayyan invented the alembic pot still, allowing for the distillation of spirituous liquors.
Ever with their finger to the pulse of continental trends, monks tucked the method of distillation into their habits and smuggled them into the far-flung lands of Eire and Alba. There, in modern-day Ireland and Scotland, the monks set up monasteries to convert the Picts and Anglo-Saxons, among others, to Christianity. Over the years, these monks refined the method of distilling the beer recipes that they had perfected over the previous centuries. From these rocky outposts emerged the artform known in varying circles as aqua vitae, eau de vie, or uisge beatha. The meaning of all these phrases? Water of life. The English later shortened the name of this art from from uisge beatha to a name you may recognize today: whiskey.
Before the days of refrigeration and steam-powered transportation, German and Scotch-Irish settlers of the nascent United States found in whiskey the only way to ensure they could get their grains to market before they went bad. As these settlers pressed west, they displaced tribes of Native Americans and planted all manner of cereals, but especially the native grain, corn.
VIII. Westward Ho, the Bandwagons!
The trend continued after the Louisiana Purchase from France -- fresh off a defeat on the Caribbean island of Sainte-Domingue -- essentially doubled the United States’ territory in 1803. With the Land Law of 1800 and the Homestead Act of 1862, Congress encouraged settlers to head ever west, in the first act lowering the land-purchase requirement to just 40 acres and in the second act giving 160 acres of public land for free as long as the settler remained for five years.
The settlers cleared away the diverse, perennial prairie grasses that had evolved alongside America’s grazing ungulates of antiquity -- the American bison, the Western horse, the llama-like Camelops -- and tried a host of crops, many unsuitable for the often semi-arid conditions. Finally, Russian immigrants imported a hardy form of wheat known as Turkey Red in the 1870s. It took off like a roadrunner from a dynamited canyon.
Many farmers ploughed entire fields under to grow the grain and nothing else. As we'll discusse in a future chapter, "Slashes to Ashes, Dust to Rust", the health of the region’s soil, so dependent on biodiversity, plummeted. Without year-round cover crops, the bellowing winter winds whisked away the region’s top soil that deep plowing had disturbed in many areas. A severe drought throughout the 1930s compounded the problem. So began one of the worst disasters in the history of the United States, the Dust Bowl. You may have heard of it. John Steinbeck certainly had. It was so bad that clouds of Midwest dust even flocked like Dementers above the streets of the nation’s Capitol one Sunday afternoon in April. The day came to be known as Black Sunday, and it terrified the politicians.
Because healthy soil can hold well upwards of 20,000 gallons more water per acre than degraded soil, U.S. farmers that had initially relied on rainfed agriculture turned increasingly to irrigation-fed agriculture. The trend accelerated in the 1950s, 60s, and 70s with Nebraska transplant Frank Zybach’s patent of the center pivot irrigation system. Irrigation west of the Mississippi was nothing new, of course. The ancient Hohokam people had irrigated their fields of corn and cotton in present-day Arizona for nearly a thousand years before Europeans arrived, but suddenly vanished around 1450 A.D. And Congress gave a slap on the rear to irrigation practices by granting land under the Desert Land Act of 1877. The Act provided 640 acres of land for $1.25 an acre to any couple that irrigated the land within three years. (Obviously, proving that irrigation had occurred was a recipe for deception.)
But, just as with those Pope Pius XII-denounced whispers of fabric known as bikinis, irrigation really took off in the middle of the 20th Century, with the center pivot irrigation system. From 1969 to 2007 alone, the amount of US farmland under irrigation grew by over 40%. The US wasn’t alone. The total water withdrawal for agriculture across the globe more than doubled between 1950 and 1995, roughly in lock-step with trends in population growth.
IX. Soviet Surface Water Missteps
One of the earliest large-scale infrastructural irrigation projects of the Industrial Era began halfway across the globe under the newly-coup-ed Soviet government. In 1918, fresh off overthrowing Czar Nicholas, balding Communist Leader and aspiring vampire accountant Vladimir Lenin devoted around 50 million roubles towards irrigating the Aral Sea in traditionally arid Kazakhstan and Uzbekistan. He wrote, “[i]rrigation will do more than anything else to revive the area and regenerate it, bury the past, and make the transition to socialism more certain.”
Under Josef Stalin, the Politburo turned up the heat in the 1940s, when they decided to grow the notoriously thirsty, high-maintenance cotton, and virtually nothing else, in this dry region. It became the northernmost cotton-growing region in the world. Engineers diverted the two main rivers that fed the Aral Sea, but failed to waterproof the canals, leading to water losses of as much as 75%.
Today, the Aral Sea has an area of fewer than 4,000 square miles, a decline of over 85% from its 26,000 square miles prior to the large-scale Soviet cotton farms. Rusting fishing boats hulk on their hulls like leaning Towers of Pisa in the middle of a cracked and decaying salt flat, checkmated. The former sea is now known as the Aralkam Desert. Pesticide-laden dust from these salt flats has wound up as far away as the blood of the Antarctic submarines known as penguins and Norwegian woods. As they say, short-sighted surface irrigation, long-term ecosystem irritation. And if they don’t, maybe they should.
X. A Gee-Ode of Global Groundwater
The Soviets weren’t alone. The water table in Kansas has dropped by an average of 23 feet in recent years. That’s about as long as London’s double-decker RouteMaster Buses, taller than a giraffe, and higher even than Larry Bird could jump. Some farmers in the state have reported more than 150 feet plunges in their water tables. And in Texas, where everything is bigger, the reservoirs are not. Due to water depletion, the area under irrigation in the Texas Panhandle has dropped more than 20% in the last 40 years. Not to mention, NASA estimated in June 2015 that one-third of the Earth’s large groundwater basins are being depleted by human consumption faster than they can recharge.
While surface water in rivers can be thought of as the hare, by turns sprinting and lazing under the candent summer sun, groundwater is quite terrapin-like, with aquifer replenishment proceeding slowly and surely, like a ‘Dark Star’ segue. One study published in the journal Nature Geosciences found that less than 6% of Earth’s aquifer groundwater has arrived in the last 50 years, the rest older even than Phil Lesh himself.
Irrigation projects, then, while often bringing with them short-term bounty, can be a real bummer for the future of the species. But do they have to be? The answer to that question brings us firmly into the present and sets us on a course for the future.
XI. A Bridge Past Troubled Water to the Future
We’ve learned much since the soil-degrading and water-wasting practices of the 19th and mid-20th Centuries. In the southern Stans of the former USSR -- you know, where we mentioned the Aral Sea has threatened to give up the coast -- Kazakhstan built a dam to retain water in the North Aral Sea. While dams are no boon to ecology, fish are at least returning to the body of water, and improved irrigation canals have reduced the amount of water wasted.
In the private arena, more sensible land management and water-use practices can have an outsized impact on eliminating the stresses on our water reserves. One simple yet oft-overlooked method is to turn off a faucet when not using the water coming out of it. I’m looking at you, oh prodigal son of the handwash, and you, oh mirror-gazer while your toothbrush foams in your mouth and runlets of water gush down the drain.
Sensible landscaping with water-efficient plants can help, too. Not to mention, they lower your water bills in the summer. Why coat your yard with Kentucky Bluegrass that requires a virtual monsoon to stay alive when you could plant native wildflowers that bloom and attract bees? In my own yard, we transitioned from thirsty roses to drought-tolerant jasmine for deliciously scented flowers.
On the topic of enjoying the outdoors with plants that aren’t dead, unless you already live in a dense forest, plant trees, then mulch them! Trees have a remarkable ability to loosen soil and increase its ability to absorb water (by upwards of 10% over treeless areas). This helps prevent runoff, thereby replenishing the groundwater that’s becoming ever more precious.
In this era of technological revolution, it’s easy and relatively inexpensive to add sensors that can easily detect leaks. While not as readily adopted in the consumer sphere, municipal governments have begun to install sensors to detect burst pipes, leaky spigots, gushing fire hydrants. If you’re the type who likes to attend city planning meetings, ask about your town’s or city’s adoption of sensors at the next meeting.
Graywater ranges from soapy water swirling down sinks to the rain rappelling off roofs. Almost always, you can divert your graywater to gardens or grass. That’s the whole premise behind rain barrels, which are cheap and relatively easy to install.
Part and parcel with getting another use out of your graywater is turning to high-efficiency fixtures and appliances. Somewhere in the range of one-third of a commercial building’s water use can come from toilets and faucets, particularly faucets that are not on timers or sensors. While the ratio is lower at home, where we take showers and wash our clothes, it makes sense both economically and environmentally to invest in low-flow toilets and showerheads and high-efficiency dishwashers and washing machines if you have the financial means. But only when the current models wear out, as the manufacture of new appliances requires significant quantities of water.
On larger scales, regenerative agriculture uses natural land contours as natural irrigation methods for rainwater, plus cover crops like clover planted beneath the cash crop, to prevent moisture loss in the summer heat and reduce irrigation requirements. (More on the principles of regenerative agriculture here and here.) Oh, and as we mentioned, healthy soil holds more than 20,000 gallons more water per acre.
On Brown’s Farm in North Dakota, father-and-son duo Gabe and Paul Brown devote 5,000 acres to Regenerative Agriculture at incredible profit. As Gabe likes to say, “we prefer to sign the backs of checks than the front.” A simple Internet search using terms like “Regenerative Farms near me” can turn up results of farmers whose conservation practices you can support with your wallet. In my hometown, Fresh Harvest and other services bring fresh, organic produce right to your door -- and you can even select a “Georgia Grown” option
Last but not least, take the time to educate your friends and family: education goes a long way towards helping ensure the continued vitality of our water reserves. If you see a friend or family member leaving the water running, gently cup your hands to your throat and roll your eyes back in your head while slowly wilting to the floor. They’ll probably get the picture.
So, as we see, the outlook is by no means Orwellian, or Eeyorean, or even Suze Orman. Individuals and governments around the world are finding great success in conserving water and ensuring the health of future generations. People just like you and me are conserving water, saving time and money.
As always, there is hope yet for our fair planet’s water. When a young Jack Nicholson arrived at the end of a labyrinthine plotline -- but one, admittedly, with very few holes -- to watch a breathy, breathtaking Faye Dunaway perish in a hail of police Pb, we were treated to a world in which water wars prove to be just that. Conflicts that can take life, both from the land and from the people residing there. But fortunately for us, 1974’s Oscar-winning Chinatown was just fiction, albeit an at-times roman a clef-esque retelling of the Owens Valley irrigation we explored earlier this essay. From water-saving devices to regenerative agriculture, from better water planning to a conscious decision by each one of us to cut down on the water we use, we have a full well of options to draw upon as we course ever-forward towards the future.
Lest we forget the fact. This is not Chinatown.
XII. Further reading
https://eprints.nwisrl.ars.usda.gov/815/1/1070.pdf (On the history of irrigation)
https://www.nature.com/articles/ngeo2590 (On the replenishment rate of groundwater)
https://www.livescience.com/51483-groundwater-basins-running-out-of-water.html; https://water.usgs.gov/edu/gwdepletion.html; https://www.nasa.gov/sites/default/files/thumbnails/image/depletion_labels.jpg (On modern-day groundwater depletion)
https://www.seeker.com/giant-mysterious-body-of-water-found-under-china-desert-1770240358.html (On China’s mysterious underground ocean and its potential to mitigate climate change)
https://www.kcet.org/shows/lost-la/beneath-our-feet-water-and-politics-in-southeast-la (On the politics of L.A. irrigation)
https://books.google.com/books?id=bhBfOqCIzLIC&pg=PA15&lpg=PA15&dq=hammurabi+water+regulation&source=bl&ots=B-uTQ_oJ5v&sig=tbPNwyjg8k4JQ1E20UnYqc4bSao&hl=en&sa=X&ved=0ahUKEwis9MrrgaHYAhVh64MKHTKqC8wQ6AEILDAB#v=onepage&q=hammurabi%20water%20regulation&f=false (On the Code of Hammurabi’s water regulations)
https://news.nationalgeographic.com/news/2014/10/141030-starstruck-earth-water-origin-vesta-science/ (On the origins of Earth’s water)
https://www.alcoholproblemsandsolutions.org/alcohol-in-the-middle-ages/#_ednref55 (On the history of distilled spirits)
https://www.archives.gov/files/calendar/genealogy-fair/2014/handouts/session-11-handout-5of5-martinez-land-other-land-acts.pdf (On the Desert Land Act of 1877 and subsequent fraud)
https://livinghistoryfarm.org/farminginthe50s/water_03.html (On the history of center-pivot irrigation)
https://www.statista.com/statistics/196377/total-irrigated-land-in-the-us-since-1969/; https://www.hydrol-earth-syst-sci.net/19/1521/2015/hess-19-1521-2015.pdf (On the growth of irrigation-fed agriculture (1) in the US, (2) globally)
https://books.google.com/books?id=Zd4_AAAAQBAJ&pg=PA257&lpg=PA257&dq=aral+sea+canals+history+1940&source=bl&ots=9_ye7ccLXN&sig=4SToC_KJifRWN0cUS4HU5fk0tAU&hl=en&sa=X&ved=0ahUKEwiQlvfw86rYAhXs7YMKHbGRDCAQ6AEIWzAL#v=onepage&q=aral%20sea%20canals%20history%201940&f=false; https://www.newscientist.com/article/mg12416910.800-soviet-cotton-threatens-a-regions-sea--and-its-children/ (On the history of the Aral Sea)
https://www.nationalgeographic.org/encyclopedia/irrigation/ (On the measures of the Kazakh government to preserve the Aral Sea)
http://www.waterhistory.org/histories/barbegal/barbegal.pdf (On the Roman Empire’s Fourth Century A.D. flour mill at Barbegal near modern-day Arles, France)
https://www.agclassroom.org/gan/timeline/crops_livestock.htm (A timeline of agricultural development in the U.S.)
http://www.popularmechanics.com/space/a14555/water-worlds-in-our-solar-system/ (On the 23 places in the solar system that we believe house water)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3394661/ (On the past, present, and future of plant root research)