The Water Behind your Meat & Potatoes
By Tamara Dean | Photos By Jim Klousia | Illustrations By Bambi Edlund 2
According to farmer Justin Isherwood, gauging precisely how much to water a vegetable crop “approaches high-energy physics.” He looks skyward and lists the variables, starting with the obvious: rainfall, air temperature, humidity, soil composition. Also, wind speed, the phase of the plant’s growth cycle, where moisture settles, the slope of the land and whether a hedge or forest abuts the field. After decades in the business, decisions become almost intuitive. But along with external factors, a farmer weighs one important internal factor—how much he’s willing to gamble.
“Without irrigation, you’re taking a risk,” says Isherwood, who grows corn, peas, soybeans, pearl millet and potatoes near Plover, Wisconsin.
Most of what we eat—80 percent of a potato, for example—is water. And producing a pound of potatoes requires about 25 gallons of water. Obviously, these gallons don’t appear in the final product. Consumers never see the water necessary to wash, process, package and ship their potatoes. Nor do most of us realize that the vast majority of water necessary to bring vegetables to our plates is what falls on fields, whether as rainwater or irrigated water.
On average, Wisconsin receives ample rainfall to grow most crops. Yet whereas early 20th-century farmers were willing to bet that rainfall would suffice, many contemporary farmers favor irrigation. Even where not strictly necessary, irrigation insures against droughts and can boost productivity.
Plover lies in Wisconsin’s Central Sands region, where soil is porous and can’t hold water for long. That makes irrigation critical. With irrigation, today’s farmers harvest ten times the mass of potatoes that Isherwood’s great-grandfather’s generation harvested from the same number of acres. And without irrigation, those potatoes would never make it to the produce aisle.
The potatoes that consumers demand—those of a certain size and uniform shape—are especially sensitive to water availability. If the plants get dry, their growth pauses. When water arrives, growth resumes. This stop-start pattern results in misshapen tubers that buyers reject. Therefore, it’s safest, Isherwood says, to water consistently, to “give the plants just a little more than what they need, making sure you’re always on top.”
The Department of Natural Resources (DNR) reports that agricultural irrigation is the state’s biggest single use of groundwater, comprising 40 percent of withdrawals, or about 250 billion gallons, in 2013. That’s enough water to fill about 379,000 Olympic-size swimming pools, or the amount of water used by 1.7 million average American families of four in a year. Most of that water was accessed using high-capacity wells, those capable of pumping 100,000 gallons of water per day.
Justin Isherwood manages 1,400 acres, an operation he deems “on the small side,” and uses six high-capacity wells. Some of his neighbors use dozens of wells. In fact, with 2,100 active irrigation wells, the Central Sands region leads the state in total groundwater withdrawals. Meanwhile, more new wells are being drilled there and elsewhere in the state at a rate of about 150 annually.
Tapping one groundwater reserve with multiple wells is often compared to letting many people sip from the same glass of water. Yet the aquifer serving the Central Sands region is not a closed system whose resources can be exhausted, like the Ogallala Aquifer beneath Nebraska. Instead, it’s recharged by rainfall. Still, in certain areas of the Central Sands, multiple high-capacity wells drain groundwater faster than rainfall can replenish it. And since groundwater feeds streams and lakes, some bodies of water, such as the Little Plover River, regularly dry up.
George Kraft, a hydrologist at the University of Wisconsin-Stevens Point, has studied groundwater pumping in the Central Sands area for decades. He and his colleagues have developed models for assessing the effects of pumping on streams and lakes. “Every new piece of evidence cements the picture we have”—that together, multiple highcapacity wells are drawing down aquifers and shrinking streams. He adds, “People’s observations are confirming what the models show.”
But thinking has not always supported the correlation between wells and disappearing waterways. Kraft says that when the Little Plover River stopped flowing for the first time in 2005, the DNR was “hostile to the idea that pumping dried up lakes and streams.” Since then, however, they have acknowledged the connection.
DNR Water Use Section Chief Eric Ebersberger points out that farming in the Central Sands is a $1 billion industry. The agency, which is charged with protecting the state’s waters, aims to balance agriculture’s needs with the health of surface waters when considering whether to approve high-capacity wells. The task is complicated by the heavy workload DNR employees face, including the ever-mounting backlog of well applications.
An additional challenge is the lack of firm direction in state policy. For a long time, the agency was not mandated to assess the cumulative impact of multiple wells on nearby groundwater. A recent court ruling stipulated that under certain conditions, they must. But some lawmakers have hinted that they want to eliminate any consideration of cumulative impacts in the near future.
Farmer Andy Diercks, who operates Coloma Farms with his father, Steve Diercks, calls the state’s current process of evaluating potential high-capacity wells “very unclear and murky,” and as a business owner, he says, “that makes it hard to make decisions.” Coloma Farms spans 2,700 acres of potatoes, corn and soybeans in the Central Sands region. Every acre is irrigated. Andy is a former president of the Wisconsin Potato and Vegetable Growers Association (WPVGA), and Steve was recently appointed to the state’s Groundwater Coordinating Council. What they want most is lasting certainty in high-capacity well policies, whether from the legislature or the courts.
Ebersberger says the best path forward starts with developing tools that predict how withdrawals will affect streams and lakes. “Get accurate information first. Then we can determine, how much impact on a stream is allowable? What are healthy levels for surface waters?” For the past few years, WPVGA has cooperated with the DNR on a project to model pumping’s effects on the Little Plover River while incorporating rainfall data and farmers’ well usage numbers.
But Kraft claims that science has already proven pumping’s effects. “The most valuable information is where we have several decades of monitoring,” he says. “Short-term [measurements] are not meaningful. We’re not even sure how much water we’re missing now.”
Andy Diercks believes that the DNR’s modeling project, which should wrap up this July, will yield valuable conclusions about one sensitive stream. And he hopes it will point to a solution for the Central Sands that farmers and environmentalists can agree on. “Very few places in the world get the recharge to the aquifer that we do,” he says. “If we can’t make it work here, that makes me pretty nervous.”
Several approaches have been suggested. Perhaps the state can assign maximum allowable withdrawals by zones based on the vulnerability of waterways in each zone. Kraft postulates that offering growers credits for certain withdrawal amounts, which they could use or sell to other growers, might work. Isherwood has floated the idea of charging a fee for each well and creating a fund that could be used to pay farmers to “farm dry,” or gamble on growing without irrigation.
Meanwhile, water-conscious consumers can influence how much water their food requires. Kraft says eating locally is a good first step. But also, he advises, “If you like lakes or streams, put your voice in with legislators and advocate for groundwater pumping that’s limited for healthy streams.”
Isherwood recommends writing letters to large buyers, such as Walmart and Sysco, to demand sustainably grown produce and express a preference for misshapen tubers over tapping groundwater until streams run dry. “You have the power. You might have more impact than what’s achieved in the laboratory or the legislature.”
And, he says, “It’s a diet issue. Eat less beef.”
Producing a pound of beef requires 1,800 gallons of water, or approximately 74 times the amount necessary to produce a pound of potatoes. But the man who originated the concept of a water footprint, Arjen Hoekstra, points out that the amount of water necessary to produce meat depends greatly on how and where livestock are raised. The largest portion of beef’s water footprint comes from the cattle’s feed. A pound of beef raised in a concentrated animal feeding operation (CAFO), where hundreds or thousands of cattle are housed in giant barns, demands more groundwater for growing feed than a pound of beef raised in a pasture. That’s because cattle raised in CAFOs eat mainly corn and soybeans grown in irrigated fields. (In fact, much of the irrigated corn in the Central Sands becomes cattle feed.) If cattle eat mainly grass, less groundwater is pumped to grow the animals’ feed.
Vince Hundt, who finishes cattle outside of Coon Valley in southwest Wisconsin, tells me there isn’t much to say about managing water in his operation. “It’s just so drop-dead simple.”
Hundt is one of several beef producers taking an unconventional, water-friendly approach to raising livestock. He practices intensive rotational grazing, in which the animals are moved to a different, small paddock daily. They drink from a trough filled by a portable water line that’s connected to a well. They feed on grass, except in winter, when they eat alfalfa that has not benefited from irrigation. They don’t eat corn or soy. In spring, when grass is lush, the cattle need very little drinking water. When they’re in a pasture, most of the water they ingest is excreted or perspired away. Their waste fertilizes the grass, and the grass is left to rest at least 30 days before it’s grazed again.
“This area begs for grazing,” Hundt says. “These hills? They’re perfect for livestock.”
Terrain and soil type on Hundt’s farm differ immensely from those on farms of the Central Sands. In southwest Wisconsin’s Driftless region, an area that the glaciers bypassed, slopes and bluffs surround winding, spring-fed streams. The soil is rich, but because of the topography, erosion and runoff are significant concerns.
In fact, Coon Valley is where Aldo Leopold helped implement the nation’s first watershed conservation project. After nearly 100 years of poor farming practices by the time he and his colleagues arrived in 1933, much of the area’s topsoil had washed downhill.
Government agents offered farmers grants and incentives to adopt more sustainable practices. Conservationists advised plowing furrows that matched the hills’ contours rather than those that ran straight up the hills. They also recommended using steeper slopes for pastures. Three generations later, the land has recovered. In August 2007, when 16 inches of rain fell in Coon Valley in less than ten hours, erosion occurred, of course, but the extent of the erosion was on par with what used to happen in the early 1900s after only two inches of rain (read more about this in "Birth of a Conservation Movement").
Jim Munsch, who also raises grass-fed beef on the steep hillsides near Coon Valley, says, “I get irked when people tell me I should be growing vegetables on my land. Corn or vegetables wouldn’t let the farm last two generations. All the soil would be gone.”
Hundt and Munsch credit grazing practices with doubling their soil’s organic matter. Higher organic matter means the ground absorbs more water, which reduces runoff. Every additional one to three percent of organic matter decreases erosion by 20 percent.* Munsch says that in his pastures, “Erosion is down to zero. After a big rain, the water coming off the field is clear.” Hundt points out that grazing is better for water quality than raising cattle in a feedlot. “The water that the soil absorbs carries no nitrates or pesticides into the aquifer.”
Both men are affiliated with the Kickapoo Grazing Initiative (KGI), a partnership of several stewardship organizations that promotes the economic and environmental benefits of grass-fed beef in the Kickapoo River Valley. Although grass-fed beef makes up only three to six percent of all beef sold in the United States, the market is expanding. For the past decade, demand has grown at an annual rate of at least 20 percent.
KGI Project Director Cynthia Olmstead likens the trend in grass-fed beef to what happened with organic food over the last 20 years. “Organics are now much more mainstream in terms of consumer knowledge and purchasing.” In the same way, she predicts consumer choice for more sustainably raised meat will further shift the market. And those changes could reverberate through our groundwater, lakes and streams.
Arjen Hoekstra, whose water footprint concept has gained traction worldwide, underscores the extent to which our eating habits affect the health and availability of Earth’s fresh water: most water usage is invisible to us. Less than four percent, Hoekstra reports, results from opening a faucet, whether showering, watering the plants or washing clothes. Meanwhile, approximately 88 percent of our water footprint is embedded in what we eat.
* Funderburg, Eddie. “What does organic matter do in soil?” Ag News and Views. August 2001. Samuel Roberts Noble Foundation, Inc.