If spread across the U.S. the
aquifer would cover all 50 states with 1.5 feet of water
If drained, it would take more than
6,000 years to refill naturally
More than 90 percent of the water
pumped is used to irrigate crops
$20 billion a year in foodand fiber
depend on the aquifer
On America’s high plains, crops in
early summer stretch to the horizon: field after verdant field
of corn, sorghum, soybeans, wheat and cotton. Framed by immense
skies now blue, now scarlet-streaked, this 800-mile expanse of
agriculture looks like it could go on forever.
It can’t.
The Ogallala Aquifer, the vast
underground reservoir that gives life to these fields, is
disappearing. In some places, the groundwater is already gone.
This is the breadbasket of America—the region that supplies at
least one fifth of the total annual U.S. agricultural harvest.
If the aquifer goes dry, more than $20 billion worth of food and
fiber will vanish from the world’s markets. And scientists say
it will take natural processes 6,000 years to refill the
reservoir.
The challenge of the Ogallala is how to
manage human demands on the layer of water that sprawls underneath
parts of eight states from South Dakota to Texas. As landowners strive
to conserve what’s left, they face a tug-of-war between economic
growth and declining natural resources. What is happening here—the
problems and solutions—is a bellwether for the rest of the planet.
High Plains farmers were blissfully
unaware a generation ago that a dilemma was already unfolding. In the
early 1950s, when Rodger Funk started farming near Garden City, Kan.,
everyone believed the water was inexhaustible. “People were drilling
wells,” he says. “You could pump all the water you wanted to pump.”
And they did. What changed everything for
Funk, now age 81, was a public meeting in the late 1960s at Garden
City Community College. State and federal geologists, who had been
studying where all that water was coming from, announced grim
findings. “They said it’s geologic water. When it’s gone, it’s gone,”
Funk says. “I remember coming home and feeling so depressed.”
Today his community in southern Kansas,
180 miles west of Wichita, is one of the High Plains areas hardest hit
by the aquifer’s decline. Groundwater level has dropped 150 feet or
more, forcing many farmers to abandon their wells. The cause is
obvious, says Mark Rude, executive director of the Southwest Kansas
Groundwater Management District: overuse.
With a liquid treasure below their feet
and a global market eager for their products, farmers here and across
the region have made a Faustian bargain—giving up long-term
conservation for short-term gain. To capitalize on economic
opportunities, landowners are knowingly “mining” a finite resource.
Choosing to use water from one of the
world’s largest aquifers rather than leaving it in the ground is not
irresponsible, says Andrew Stone, executive director of the American
Groundwater Trust in Concord, N.H. Like coal or natural gas,
groundwater is a valuable resource. “There is no benefit to mankind to
keeping it unused in cold storage,” Stone says. The challenge is to
stretch the life of the aquifer to benefit future generations of
farmers and those who depend on their products.
In Garden City, however, the severity of
their circumstances is already forcing farmers to take action. They
are grappling with how to maintain successful agricultural operations
while relying on less and less water, an issue that water users
throughout the region, and the world, must eventually face, Rude says.
“The community of water users needs to figure this out,” he adds.
“We’ll get to sustainability one way or another, but it may be
sustaining an economy without the Ogallala Aquifer.”
Tapping the Aquifer
On a hydrographic map, the Ogallala is a Rorschach inkblot that some
describe as the shape of a mushroom, others the South American
continent. Millions of years ago, when the southern Rocky Mountains
were still spewing lava, rivers and streams cut channels that carried
stony pieces of the mountains eastward. Sediment eventually covered
the area and filled in the ancient channels, creating vast plains. The
water that permeates the buried gravel is mostly from the vanished
rivers. It has been down there for at least three million years,
percolating slowly in a saturated gravel bed that varies from more
than 1,000 feet thick in the North to a few feet in the Southwest.
Until recently, most of the region had no
permanent settlements. Native American tribes who used the open plains
for seasonal hunting retreated to river valleys to pitch their tents.
When Spanish conquistador Francisco Vazquez de Coronado came through
in 1541 looking for the gold cities of Cibola, he marched his
iron-clad men to the brink of exhaustion, never knowing that water to
quench their near-maddening thirst lay mere yards beneath their boots.
Similarly, cattle drives in the 1860s and 1870s collapsed in a perfect
storm of drought, overgrazing and falling meat prices. And early
attempts at farming were plagued by soil erosion and cycles of drought
that culminated in the 1930s Dust Bowl.
Industrial-scale extraction of the
aquifer did not begin until after World War II. Diesel-powered pumps
replaced windmills, increasing output from a few gallons a minute to
hundreds. Over the next 20 years the High Plains turned from brown to
green. The number of irrigation wells in West Texas alone exploded
from 1,166 in 1937 to more than 66,000 in 1971. By 1977 one of the
poorest farming regions in the country had been transformed into one
of the wealthiest, raising much of the nation’s agricultural exports
and fattening 40 percent of its grain-fed beef.
But the miracle of new pumping technology
was taking its toll below the prairie. By 1980 water levels had
dropped by an average of nearly 10 feet throughout the region. In the
central and southern parts of the High Plains some declines exceeded
100 feet. Concerned public officials turned to the U.S. Geological
Survey, which has studied the aquifer since the early 1900s. With
their state and local counterparts, USGS officials began monitoring
more than 7,000 wells to assess the annual water-level changes.
What they found was alarming: yearly
groundwater withdrawals quintupled between 1949 and 1974. In some
places farmers were withdrawing four to six feet a year, while nature
was putting back half an inch. In 1975 the overdraft equaled the flow
of the Colorado River. Today the Ogallala Aquifer is being depleted at
an annual volume equivalent to 18 Colorado Rivers. Although
precipitation and river systems are recharging a few parts of the
northern aquifer, in most places nature cannot keep up with human
demands. “We have optimistic locations. Other places we can see the
end,” says David Pope, who administered groundwater regulations in
Kansas from 1983 to 2007 as the state’s chief engineer.
Sustainable Solutions
For Funk, the depressing data he took home from that Garden City
meeting was transforming. Whereas other farmers responded to declining
water levels by adding wells, Funk eliminated them: “We decided to go
dryland.” Today he pumps almost no water on his 6,000 acres, which are
planted largely in wheat and grain sorghum. These crops are typically
not as lucrative as corn, but they are sustaining Funk’s family. To
farm without groundwater, Funk has changed some of his methods.
Instead of plowing his fields after harvest, he leaves the stubble in
the ground and plants a new crop in the residue. This technique not
only reduces soil erosion but also decreases evaporation and catches
more blowing snow than bare ground. Leaving crop residue in the field
can reduce moisture loss by the equivalent of an inch or more of
rainfall annually, scientists say. Funk aims to capture every bit of
the 18 inches of precipitation that fall on southwestern Kansas. “Got
to,” he says. “It’s all we’ve got around here.”
Funk is part of a small but steady
movement away from groundwater dependence. The scientific certainty of
Ogallala’s decline has spurred an interest in conservation throughout
the region. Researchers are developing less thirsty crops, including
drought-tolerant corn. Their goal is to reduce the amount of water
corn crops require by at least 10 percent, says Wenwei Xu, a research
scientist at Texas A&M. The Ogallala Initiative, a U.S. Department of
Agriculture project, funds studies designed to make the agricultural
industry—and the rural communities that depend on it—more sustainable.
An annual $3.6-million congressional appropriation supports the
research, ranging from irrigation techniques and precipitation
management to animal feedlot operations.
At a USDA research station near Amarillo,
Tex., scientists are compiling data that encourage Funk and other
farmers to use low- or no-till techniques (such as leaving crop
residue to decompose), says Nolan Clark, station director and an
agricultural engineer. Other projects aim to bring high tech down
home. Engineers have installed 16 wireless infrared sensors on the arm
of a center-pivot system used to irrigate cotton in a research plot.
The sensors are calibrated to measure leaf temperatures, allowing the
plants themselves to tell computer-controlled irrigation equipment
when they are thirsty. At a scientifically determined threshold, the
sprinklers turn on automatically. Because these robotic irrigation
systems apply water only when it is needed, in test fields they are
saving two inches per crop per season, Clark says.
Evapotranspiration is another way plants
can communicate with high-tech irrigation systems. Researchers are
designing equipment that uses lasers to measure the turbulence caused
by heat waves above crops. The greater the turbulence, the more water
plants need. The laser equipment will eventually estimate daily
evapotranspiration rates on a regional scale. These will be posted on
the Internet, giving farmers information they can use to adjust their
irrigation to the needs of their crops.
Such devices may not save dramatic
amounts of water, but in West Texas, where the Ogallala is in rapid
decline, they are critical. A savings of 10 to 15 percent per crop per
season spread over millions of acres—“that’s a significant amount of
water,” Clark says. “We may not make the aquifer sustainable, but we
may give it another 100 years.”
New Demands
Yet even as these innovations move from experimental plots to
production fields, improvements in efficiency may be offset by new
demands on groundwater. Biofuels are the latest enticement to grow
corn, which garners higher profits but requires more water than most
other crops. Plans to double the number of ethanol production
facilities in the High Plains region are driving farmers to increase
corn production despite already scarce groundwater. That could require
up to 120 billion additional gallons of Ogallala water annually,
according to a report by the Environmental Defense Fund (EDF).
Growing populations throughout the Great
Plains region are also demanding more municipal water from the only
available source: the aquifer. T. Boone Pickens, the billionaire
oilman and recent alternative energy advocate, is among the
entrepreneurs who have entered the domestic water market. A Texas law
granting landowners unrestricted rights to the water beneath their
property makes it possible for Pickens to sell groundwater from his
24,000-acre Mesa Vista Ranch in the Texas panhandle to metropolises as
far away as Dallas and El Paso. The 654-mile pipeline he plans to
build to El Paso would cost $2.1 billion. But with water sales priced
at more than $1,000 an acre-foot, profit is waiting to be had.
Looming over these new demands for the
Ogallala’s finite water supply is climate change. Although
precipitation in Nebraska at the northern end of the aquifer will
likely increase, scientists predict the southern parts of the region
will get even less than the 16 inches of annual precipitation they now
receive.
In the face of these combined demands
on the already overtapped aquifer, many High Plains water users
are joining Funk in reassessing their futures. No matter how
efficiently they use it, they know the groundwater will
eventually be gone—leaving them, their communities, and most of
the region high and dry. Like Funk, they are starting to make
plans for a time when the Ogallala will not meet their economic
needs. Some growers are joining Funk in moving to dryland
farming—growing wheat and other crops that do not require
irrigation. In eastern Colorado, farmers are planting hardy
sunflowers, which require 30 percent less water than corn.
Other farmers are turning to native
grasslands for economic alternatives. Before European settlers
arrived, the billion acres of grasses that blanketed the High
Plains were home to pronghorn antelope and swift fox, lesser
prairie chickens and burrowing owls as well as buffalo. Blue
grama, green needle grass and other drought-resistant plants
thrived in the short growing season. More than half these native
grasslands have been converted to crops, including nearly 25
million acres since 1982, according to a 2007 General Accounting
Office study.
A return to grasslands could be a
potential source of income, says Amy Hardberger, an attorney
with the EDF in Austin, Tex. In a project she is coordinating,
farmers are experimenting with grassland restoration on fields
they have been forced to retire because of groundwater
depletions. In addition to providing wildlife habitat,
grasslands could be grazed by cattle or even buffalo. Hunting,
ecotourism and “dude ranches” are other potential sources of
income from grasslands. And once a national carbon market is
established, farmers could sell credits for storing carbon in
grassland soil. “This is a tough group of people,” says
Hardberger, whose grandfather raised cotton near Lubbock, Tex.
“They don’t want to leave their land—and they shouldn’t have
to.”
Several federal government programs
provide economic incentives for conservation of existing
grasslands—recognizing their role in reducing erosion,
sequestering carbon, and providing habitat for the lesser
prairie chicken and other endangered species. But these programs
often work at cross-purposes with federal price-support
incentives to produce corn and other commodities. Subsidies for
crops are generally higher than subsidies for grassland
conservation, making the choice simple for most growers.
The contradictions in these federal
programs reflect America’s ambivalence about the Ogallala
Aquifer. Eventually the nation will need a strategy to end its
dependence on this finite resource, says Stone, the Groundwater
Trust executive. But for now, across much of the High Plains
it’s business as usual: drilling and pumping water, irrigating
and growing crops as if the Ogallala era will never end.
For Funk in Garden City, it already
has. Using technology and foresight, he has transformed his farm
into a business he believes can continue into the distant future
without draining the Ogallala. “Forever? We hope so,” he says.
“That’s been our goal.”
Note: This article was
originally printed with the title, "Saving the Ogallala
Aquifer".
This article was originally published
with the title "Saving the Ogallala Aquifer" in SA Special Editions
19, 1s, 32-39 (March 2009)
doi:10.1038/scientificamericanearth0309-32
ABOUT THE AUTHOR(S)
Jane Braxton Little is a writer and
photographer based in Plumas County, Calif. She wrote about restoring
the Borneo rain forest in the previous issue of Scientific
American Earth 3.0.
