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September 20th, 2016
Via Pacific Standard, an interesting look at how irrigation helped create America’s breadbasket and how it threatens to destroy it:
Rick Hammond turned a yellow dial until it locked into place with a hollow clank, and a high-pressure hum filled the air. Across the windswept field, a light started blinking atop a metal contraption that stretched a quarter mile from end to end, adorned with an array of dangling hoses and sprinkler heads. With a humped metal spine and rib-like trusses, it looked like the skeleton of some sort of robotic brontosaurus.
Hammond tipped his cowboy hat back with his thumb to get a closer look at the display on the sky-blue control panel emblazoned with the logo forValley Irrigation. He checked the readouts for speed and pump pressure and then pointed to the flashing light. “That means everything is on. Then you start it walking,” he said. And with the push of a button, the enormous center-pivot irrigation system lumbered to life, the twinned drive wheels under each triangular tower creeping slowly clockwise.
“What we’re shooting for on this level of ground is about an inch,” Hammond said over the wind and roar of the pressurizing wellhead. “It won’t run off with an inch. That takes approximately three and a half days.” In a good growing season, he hoped to put just three to four inches of water on this 160-acre field in York County, Nebraska. That doesn’t sound like much, but Hammond showed me the meter. “Look at that,” he said, pointing to the small lettering under the spinning numbers gauge. “Gallons times one hundred. We’re talking millions of gallons of water,” all of it pumped straight from the Ogallala Aquifer.
Those millions of gallons are starting to add up. A recent study of United States Geological Survey data compared the depths of more than 32,000 wells nationwide over the last two decades. The results were alarming. Across the country, water levels have fallen in 64 percent of all wells, with an average decline of more than 10 feet. In the Ogallala Aquifer system, which supplies groundwater for crop irrigation to eight states from Texas to South Dakota, the declines are especially pronounced. In much of southwestern Kansas, wells are down to 25 percent of the water that existed when the aquifer was first tapped less than 70 years ago. In the southern High Plains of Texas, near the edge of the Ogallala, water levels have fallen more than 100 feet in places, leaving many farmers without any water at all.
Two years ago, the State of Texas published a report on water level changes since groundwater irrigation began on a large scale. “Since the 1940s,” the report stated, “substantial pumping from the Ogallala has drawn the aquifer down more than 300 feet in some areas.” The U.S. Department of Agriculture went on to invest over $70 million in the Ogallala Aquifer region, “to help farmers and ranchers conserve billions of gallons of water.” But the Great Plains was soon plunged into a multi-year drought, and, instead of declining, water usage shot up dramatically.
Finding water to grow food has been the central challenge of life on the Great Plains since the earliest days of white settlement. In its zeal to displace Native Americans and “tame” the prairies, the U.S. government passed the first Homestead Act in 1862 and platted a patchwork of one-mile squares, which were then subdivided into quarters of 160 acres each. A “quarter-section” could be claimed by any free citizen of the U.S., man or woman, native-born or immigrant, with just one major catch: You had to live on the land and farm it for at least five years. This not only meant concocting some way of building a home on the treeless prairie, but also finding enough fresh water to sustain crops.
On the semi-arid plains of Nebraska, where surface streams often ran dry during the summer months?—?right when water for irrigation was most needed?—?farmers had little choice but to dig wells, with nothing more than shovels and picks at their disposal. Soon, windmills were erected, allowing farmers to pump groundwater and divert it to the wide furrows of their fields or into catchment ponds. Life on the hardscrabble plains was arduous, and often hand-to-mouth. Nevertheless, by 1890, the Homestead Act had settled some two million people on nearly 375,000 farms.
But in the years that followed, just as cities like St. Louis, Omaha, and Denver were turning into bustling metropolises built on income from livestock and grain exchanges, the entire Great Plains was devastated by drought and blistering heat. By the harvest of 1894, one newspaper reported, nearly 38 percent of acres planted with corn in the middle states were either destroyed or abandoned. In Nebraska, where high temperatures were accompanied by scorching winds, the smell of parched corn filled the air. Many farmers packed up and left, making their escape, according to another paper, “while they had something to do it with.” The drought revealed that raising enough grain for a farm family to thrive would require greater land allocations than the Homestead Act had originally provided?—?and a lot more water.
In western Nebraska, groups of farmers banded together to dig miles of irrigation canals, diverting water from the North Platte River, but they still didn’t have enough to expand their fields and sustain those crops through the summer. So the U.S. Army Corps of Engineers ordered a survey of sites where dams could be built in the foothills of the Rockies, and the USGS simultaneously commissioned a study of groundwater resources on the Great Plains.
In 1897, working at a spot west of Ogallala, Nebraska, government geologist N.H. Darton surmised that the abundant wells of southwest Nebraska had tapped a great storehouse of ancient water held in place by an enormous underlying layer of limestone. “Extending from Kansas and Colorado far into Nebraska,” Darton wrote, “there is a calcareous formation of late Tertiary age to which I wish to apply the distinctive name Ogalalla formation.”
Unfortunately for the early settlers, there was no efficient way to convey those groundwater resources to the surface. A single windmill could only pump enough water to irrigate five acres or provide for 30 cattle?—?hardly enough to get farmers through the dry years. In 1928, the Nebraska Agricultural Extension Service lamented that “the underground water supply is abundant,” but there were insufcient means of “lifting it to the surface and applying it to the land.”
As the country struggled through the Dust Bowl and the wartime food rationing that followed, agricultural engineers grew determined to find some way to make use of that untapped resource.
During World War II, companies like John Deere, Caterpillar, and International Harvester boomed under government contracts, designing and assembling engines for heavy trucks and tanks. After the war, they shifted resources to developing pumps that could finally convey all of that groundwater to the surface.
Early irrigation systems, however, were little more than a pump connected to a series of metal pipes that had to be lugged into place and then re-set two or three times a day. It was a mucky and painstaking job, and not a terribly efficient one. A farmer named Frank Zybach thought there had to be a better way. After attending an Irrigation Field Day in Colorado, where he watched the demonstration crew set the pipes, then tromp through the mud to move them, Zybach began developing a self-propelled system in which the force of water flowing through the irrigation tube would slowly turn the drivetrain of supporting wheels. By anchoring the pipe to a central wellhead, the system turned in a perfect circle, watering the field evenly without any work by the farmer. Zybach’s system became known as “center-pivot irrigation.”
Despite their novelty, early center pivots were plagued by malfunctions and were a nightmare to maintain. Farmers, leery of the expense and hassle, were reluctant to buy. In the first two years of production, Zybach told theLincoln Journal-Star, he and his business partner A.E. Trowbridge sold just 19 center pivots. They decided to license the technology to Robert B. Daugherty, the young owner of a small farm equipment company called Valley Manufacturing, whom they hoped could improve the design and make the system profitable.
In 1953, furnace-like temperatures spread across the Central Plains, pushing hot, dry air across the American breadbasket. The drought that followed held the region relentlessly in its grip. For nearly four years, the middle of the country, from the panhandle of Texas all the way to the Sandhills of Nebraska, experienced low rainfall and stretches where the mercury topped 100 degrees for weeks at a time. The federal government spent $3.3 billion on assistance to farmers, and the beef industry in Texas was nearly destroyed in what became known as the Great Cattle Bust.
But farmers in eastern Nebraska were able to weather through on account of their abundant groundwater and the advent of center-pivot irrigation. Other pivot manufacturers soon popped up around eastern Nebraska?—?Zimmatic in Lindsay, Reinke in Deshler, and Olson Brothers in Atkinson?—?and then began setting up dealerships across the Great Plains. In the decades that followed, farmers from North Dakota to Texas turned to center-pivot irrigation to provide extra water during key growing times and help them through dry spells.
By the end of the 1970s, there were more than 18,000 center pivots operating in Nebraska alone and some 30,000 in other parts of the Great Plains, altogether irrigating more than 20 million acres. The rapid expansion of center-pivot technology allowed farmers to plant on more and more marginal land and to venture into water-intensive crops, leading to dense planting of corn. In just a few short decades, the arid plains were transformed.
The changes were so profound that astronauts aboard Skylab reported seeing a checkerboard of round green circles stretching for miles across north-central Nebraska. “Passengers on commercial jet airliners increasingly notice the same sight,” wrote William E. Splinter, chair of the Department of Agricultural Engineering at the University of Nebraska, in an article forScientific American. “What is being observed is perhaps the most significant mechanical innovation in agriculture since the replacement of draft animals by the tractor.”
None of this would have been possible without the Ogallala. But how long can it last?
To answer that question, Ann Bleed, a former state hydrologist and director of the Nebraska Department of Natural Resources, says that we first have to understand that the Ogallala Aquifer isn’t one single aquifer but many aquifers, studied and managed as independent parts of the High Plains Aquifer System. When the system began to form over 100 million years ago with the uplifting of the Rocky Mountains, the shallow inland sea that had covered much of North America slowly receded, and rain and snow from the rising craggy peaks ran off, forming rivers that ran east from the mountains to the flatlands. In time, the braided channels filled with silt and gravel, creating spaces that trapped a vast reservoir of freshwater under the alluvial soil.
Contrary to popular views, however, an aquifer is not a giant underground lake. It is more complicated than that. In places where rivers once ran, the Ogallala can be quite deep, but in areas where bedrock is high, it may be shallow and cut off from other parts of the system. So some parts of the aquifer, like those in eastern and central Nebraska, can replenish, or “re-charge,” rather quickly, but, for many, it takes hundreds of years. Still others, like the aquifers underlying western Kansas and wide swaths of the Texas Panhandle, refill so slowly it’s as if they don’t re-charge at all; geologists call their water “fossil water,” because it is more akin to oil, a finite and non-renewable resource.
Bleed emphasizes that aquifers naturally re-charge by the action of surface water slowly percolating down to the more porous layers underneath. Rising temperatures and more frequent droughts mean greater demands on that surface water. Which means less water is available for re-charge at the very times that farmers are already drawing groundwater more rapidly because of the heat. For decades, farmers tried to drill their way out of the problem. When water tables sank and wells failed, they simply dug deeper or dug elsewhere. But now, in some parts of the system, farmers have depleted the groundwater all the way down to the bedrock. And the re-charge rate is so slow in some of these places that the aquifer won’t refill for thousands of years. For all intents and purposes, that water is never coming back.
Don Wilhite, founding director of both the National Drought Mitigation Center and the International Drought Information Center at the University of Nebraska–Lincoln, believes that the effects of this rapid drawdown could be catastrophic. The author of over 150 journal articles, monographs, book chapters, and technical reports on drought and drought management, Wilhite is known in academic and agricultural circles as “Dr. Drought.” In 2013, he garnered public attention by refusing to participate in a state climate-change impact study after the Nebraska legislature passed a bill precluding contributing scientists from addressing the role of human activity. “I couldn’t write a report that would exclude human causes,” Wilhite said at the time. “To be of any use, a climate impact report has to look at the whole picture. The issue is one of science, not politics.”
When several other climatologists also declined to join the team, the Institute of Agriculture and Natural Resources at the University of Nebraska–Lincoln announced that it would conduct its own study, led by Wilhite. (The Nebraska governor, in turn, decided to cancel the government-led investigation.) The IANR released its findings a year later?—?and its language couldn’t have been more forceful. Not only did it conclude that human activity is implicated in global climate change, it chastened those who sought to create the illusion of scientific disagreement. Wilhite took the message to the local media, insisting that farmers and others dependent on the agricultural industry should set an example by finding ways to mitigate climate change, rather than denying its effects, because they stand to feel the impact of those changes most immediately. He warned that greenhouse gas emissions, if unchecked, will cause temperatures in Nebraska to increase by as much as nine degrees Fahrenheit in less than 50 years. By then, he said, groundwater resources could be so depleted that they won’t be able to rescue farmers from the never-ending drought.
At a talk last fall in Lincoln, a capacity crowd squeezed into the sanctuary of the Unitarian Church to hear Wilhite explain the report’s findings. The audience ranged from environmental activists to area farmers who seemed to be taking heed of Wilhite’s warnings. He told the crowd that the projected increase in temperatures means that summertime highs will regularly surpass 100 degrees Fahrenheit. Those extremes falling, as they will, during the peak of the growing season?—?right before and right after pollination, when even the most cautious and judicious farmers turn on their pivots—will create untenable demands on groundwater. Even if rainfall were to increase, it would not be enough to offset the loss of soil moisture caused by extreme heat. In a hotter climate, it will take more water to generate the same crop yield, even with genetically modified grain hybrids. Unless we change farming and water management, he explained, there simply won’t be enough groundwater to combat such dry conditions.
Most importantly, Wilhite said that the loss of groundwater resources would set off a feedback loop with much broader effects. He explained that pumping all of that deep, cold water from the Ogallala and spreading it across many acres has artificially lowered air temperatures and increased humidity. That human-induced microclimate has masked the effects of climate change by forestalling climbing temperatures on a regional level. If we run out of that water, temperatures will rise further. Crippling drought will become the new norm, turning the Central Plains states into a permanent dust bowl.
Wilhite’s greatest worry, he told the crowd, is that farmers tend to brush off such dire predictions, insisting that they have lived through many hard times. They say that their grandfathers got through the Dirty Thirties and innovated their way out of the Great Cattle Bust in the 1950s. “Farmers say they’re used to variability,” Wilhite said, “but these projections are wayoutside the range of anything we’ve ever encountered.”
A tower from one of Robert Daugherty’s original center-pivot systems is on display in the lobby at Valley Irrigation’s manufacturing headquarters in Valley, Nebraska. Matt Ondrejko, vice president for global marketing, told me that the exhibit honors Valley’s central role in averting agricultural disaster in the 1950s and building the large-scale ag economy that followed. Touring the sprawling complex of factories and machine shops bounded by test fields, it’s clear that the folks at Valley recognize how much the future of the company depends on continuing to innovate, particularly in the area of water conservation.
“We can’t run a business selling irrigation systems if there’s no groundwater for irrigation,” Ondrejko said. The company is able to tackle the challenge by closely monitoring every step of the construction of its center-pivot units?—?from the hand assembly of the plastic sprinkler nozzles to a massive crane system that lowers spans of pipe into a gargantuan zinc-and-nickel bath.In recent years, Valley has focused its research and design improvements on two main areas: the sprinkler heads and the control mechanisms. By collecting field-moisture data and contrasting yield returns in comparable fields irrigated with different sprinkler heads, engineers are able to “refine the spray patterns and the drop patterns, to reduce loss through evaporation.” The latest design innovations have focused less on fine droplet dispersal and more on getting water all the way to ground level. After all, the goal is watering root systems, not leaving droplets on leaf surfaces where they will be lost. “There’s really precise science in how big the drop is,” Ondrejko said, and “how close we get it to the ground.”
Valley has also invested in developing variable-rate irrigation, which allows individual sprinkler heads to be turned on and off in particular parts of the span as it passes over different sections of the eld. The goal, Ondrejko said, is being able “to precisely spoon-feed the crop?—?when it needs it, where it needs it, no more, no less.” Perhaps most important is the development of exact application monitoring, so that farmers can collect precise information on how many acre-inches they are using and where. That’s where technology meets water management efforts in the field.
Nebraska is broken into 23 Natural Resources Districts, which were created in 1972 to manage resources at the individual watershed level. Over the years, some NRDs have started requiring metering on new wells, which has helped farmers to track field-by-field usage and encouraged them to reduce their draft. And some, like the Upper Big Blue Natural Resources District (which oversees usage in east-central Nebraska, including most of Rick Hammond’s fields), have undertaken even more ambitious initiatives.
The Upper Big Blue, which contains significant acreage classiffed as “high risk groundwater areas,” launched a study in 2012 comparing crop yields in neighboring fields with identical center-pivot irrigation systems?—?but with one managed by the farmer and the other managed by the NRD. The farmer applied water according to his own judgment, while the NRD used soil-moisture data collected from a network of monitors inserted into the edges of the field. The NRD achieved a nearly identical yield?—?98 percent of what the farmer harvested?—?while drawing only a third of the water. The latest advancement is a wireless soil-moisture monitoring system that sends data to the farmer electronically. Future improvements will send that data directly to the center pivot, automatically turning the system on when irrigation is needed, and applying water only in the necessary areas. It’s hoped that these new technologies will be able to universally drop usage in these high-risk areas to the point that the aquifer might actually begin to re-charge.
Will it work? David Eigenberg, who heads the Upper Big Blue NRD, told me that technology has led the way to improved irrigation efficiency, but to really reduce water usage, you have to shift from being a culture that views groundwater irrigation as an individual right to one that sees it as a shared resource. And that means reversing the drawdown is about more than high-tech equipment; it’s about reaching “the guy in the tractor seat.”
But even bigger, more sweeping changes may be needed. To address the problem adequately, we may need to re-think what kind of food we grow where, and how much agriculture is feasible in certain landscapes. The center pivot allowed the re-population of many areas that had been vacated during the Dust Bowl?—?areas that simply couldn’t sustain crops without a new source of water. That new technology, coupled with other advances in agriculture, put more than 100 million acres of marginal land into farm production, much of it for growing water-intensive crops, like corn and soybeans, which today are raised primarily for livestock feed and biofuel, not for human consumption. Farmers have also been encouraged to turn away from more drought-resistant cash crops?—?such as sugar beets in western Nebraska and sorghum in Oklahoma?—?in favor of commodity grains that are supported by higher farm subsidies and crop insurance.
The Ogallala water boom made it possible for the U.S. to maintain the Cold War balance of power by becoming the world’s granary, but now, as wells run dry in western Texas, Oklahoma, and Kansas, some agricultural operations are on the move. Instead of learning from the mistakes of the past, they are simply following the water.
After the most recent drought, for example, Cargill, Inc., one of the three biggest beef producers in America, sold its feedlots and shuttered its largest processing facility in the Texas Panhandle, shifting production to its plant in Dodge City, Kansas. Because meat producers prefer to shave margins by concentrating all phases of production, this means that not only are more cattle being watered there, but more corn and soybeans are needed to fatten those cattle for slaughter. A whopping 40 percent of all grain-fed beef in the U.S. is produced using water from the Ogallala.
Optimists will point out that there are wide swaths of central and eastern Nebraska where groundwater levels have held steady or even increased in recent decades. York and Hamilton counties, where Rick Hammond raises corn and soybeans, are two of the most intensively farmed and heavily irrigated parts of the state, yet water levels there have only fallen by a depth of about five feet. But Hammond isn’t resting easy.
After he was done showing me how his center pivot worked and had shut the system down, he confided that he worried about the long-term future of industrialized agriculture on the Great Plains. “I have seen nature repair itself,” he said, but that process is often slow. “If humans don’t give it a chance, I think it could be bad.” If rainfall patterns keep changing and people don’t conserve groundwater, he said, “there will just be grass in Nebraska.”
He grew up in the western part of the state, not far from where archaeological digs have uncovered an ancient ancestor to the Pawnee?—?people who thrived there for hundreds of years before being displaced. The sites of many of their villages have been found buried under a thick shroud of dust?—?evidence of a drought that lasted generations, Hammond said. “Could it happen across the Great Plains today?” he asked. “Absolutely.”