This story by Allen Best appeared on ‘Big Pivots’ on December 27, 2022. It was first published in the summer 2022 issue of Headwaters Magazine. We are sharing it in four installments.
The 2019 Technical Update to the Colorado Water Plan projects that 6% to 7% of irrigated acres supplied by groundwater in the state will be lost due to aquifer sustainability issues, primarily in the Arkansas, Republican and Rio Grande basins.
Water conservation districts formed in the last 20 years are paying farmers to decrease pumping and planting to save the water that remains in the aquifers, comply with compacts, and transition to less water use.
Directors of the Republican River Water Conservation District, in northeastern Colorado, where producers rely on Ogallala aquifer water, were confident and successful in incentivizing the voluntary retirement of 4,000 acres by June 2020. They are confident of inducing the retirement of 10,000 acres in the area between Wray and Burlington before 2025. The aquifer there has been falling 8 inches a year. They’re less sure of achieving the 25,000 acres that compact compliance will require by 2029.
Rio Grande Water Conservation District directors in south-central Colorado have an even greater lift. They must figure out how to retire 40,000 irrigated acres by 2029. They’re at 13,000.
High commodity prices have discouraged farmer participation. The pot of local, state and federal money hasn’t been sufficient to fund high enough incentives to compete with commodity pricing. A bill, SB22-028, Groundwater Compact Compliance Fund, which passed in the Colorado Legislature in May, will allocate $60 million to both the Republican and Rio Grande basins to help them comply with interstate river compacts by reducing the acreage outlined above. The law says that if voluntary reductions cannot be attained, Colorado may resort to mandatory reductions in groundwater extraction.
Even if the Republican River Water Conservation District’s 2029 deadline is met, the basin’s long-term outcome remains uncertain, says Rod Lenz, president of the district’s board of directors. Lenz’s family migrated from Weld County to the Republican River Basin in 1974. It was a boom time, not unlike Colorado’s gold- and silver-mining era, in this case producing wealth by mining the Ogallala using the new technology of center-pivot sprinklers.
Taking the long, big picture view, Colorado spent most of its first 100 to 150 years as a state developing its water resources.
Colorado’s farmers first settled in places where water was most plentiful, along its creeks and rivers. Among the last places to see the plow was land along the Kansas and Nebraska borders. Dryland farming, fed only by rain, came first, then gasoline-powered pumps allowed limited pumping of water from the underlying aquifers.
Center-pivot sprinklers dramatically expanded the geography available for farming. Don Brown remembers well the transformation. On the Brown family farm, his father commissioned what may have been the first circular sprinkler in Yuma County to use the Ogallala aquifer.
Brown, a former agriculture commissioner for Colorado, says that a 425-foot well was drilled in 1962, when he was a boy. It cost $10,970 — a “fortune back then,” says Brown. The center-pivot sprinkler cost was in the same price range, another fortune. Brown’s father was so concerned about whether the technology was right that he summoned the inventor to inspect it. Frank Zybach had invented the technology in 1940 while farming at Strasburg, east of Denver.
Was it worth it? The jury was soon in. “One season, 150 days,” says Brown. “It worked!”
Irrigation was available for corn’s full growing season. With that, farmers had a new model for irrigation in Yuma County, one independent of rainfall and flood irrigation.
Other center-pivot sprinklers soon followed, expanding the amount of land in the rolling hills of the Republican River Basin available for irrigation. In turn, the water expanded the yields. Dryland corn might yield 50 or 60 bushels per acre. Irrigation boosts yields to 300 bushels.
Irrigation vaulted Yuma County into one of the nation’s top-producing agricultural counties, where it remains.
That phase of irrigated agriculture, the development of new water sources, has now almost entirely ended. The bucket is virtually empty. The new era poses an inverse challenge: sustaining agriculture with less water.
Even as center-pivot sprinklers are removed in the Republican River Basin and San Luis Valley, they are going up in the Grand Valley of western Colorado. There, instead of drafting groundwater, they are distributing Colorado River water.
The geography of the valley from Palisade to Fruita and Loma does not immediately favor center pivots. They work best as a pie within a square, a full 40 or 160 acres. Parcels in the Grand Valley tend to be more rectangular. That means a pivot can arc maybe three-quarters of a circle. That slows the payoff on investment.
Why the pivot, so to speak, on pivots? Perry Cabot, a water resource specialist with Colorado State University’s Western Colorado Research Center near Fruita, sees two, sometimes overlapping, motivations. (Cabot also serves on the Water Education Colorado Board of Trustees.)
The greater motivation is the desire to save labor. That itself is good, he says, because the investment reflects an intention to continue farming. “People are obviously doing it for the long haul,” he says.
The other motivation appears to be water related. “The feedback I get is, to paraphrase the farmers, at some point in the future we are going to have less water to farm with and so we must prepare for that,” Cabot says.
Incremental improvements have improved efficiency. Experiments at the CSU research center in Walsh have shown conclusively the advantage of long-drop nozzles that spray the water just a couple feet off the ground, reducing evaporation.
Technology can help perfect a producer’s irrigation set up. Consider work in the San Luis Valley by Agro Engineering, crop consultants who seek to assist growers in producing maximum value with minimum water application. Potatoes, the valley’s largest cash crop, thrive in warm, but not hot, days and cool nights. They need 16 to 18 inches of water per year, of which 13 to 15 inches comes from irrigation. This includes two inches applied during planting, to moisten soils sufficiently for germination. They do not do well with too much water, explains Jason Lorenz, an agricultural engineer who is a partner in the firm. That, and the need to align use with legal requirements, gives growers compelling reason to closely monitor water.
To evenly distribute water, Agro Engineering first checks sprinkler vents, to be sure they are working properly. “You won’t get any more yield by over-applying water,” Lorenz observes.
Later, the company uses aerial surveys conducted from airplanes to analyze whether the desired uniformity is being achieved. The latest advancement, multispectral aerial photography, enables the detection of green, red and near-infrared light levels. These images indicate the amount of vegetative biomass, vegetative vigor, and the greenness of the leaves. Variations show where crops are healthier and where there are problems, including insects and diseases, water quality, or soil chemistry problems.
Any discussion of water and agriculture in Colorado must include a focus on corn.
In 2021, according to the U.S. Department of Agriculture, almost 1.4 million acres in the state were devoted to corn, with well more than half of that irrigated.
Allen Best publishes the e-journal Big Pivots, which chronicles the energy transition in Colorado and beyond.