Wasting Water While Growing Hay

“Without waste” is a phrase one rarely hears at water meetings, especially in the context of this quote from Colorado Supreme Court Justice Gregg Hobbs: “… the water itself is owned by the public and actual beneficial use without waste is the limit, scope, and measure of a water use right so that others may have their place in the priority system … “ The sentence is from the foreword Hobbs wrote for the book, Water: Colorado’s Real Gold, by Richard Stenzel and Tom Czech, which was published in 2013. I added the italics to “without waste,” because waste is key to unlocking how to leave more waters in the river. That and growing less hay.

But do the division engineers in each of the seven water divisions in Colorado call out waste? Not very often.

One reason is that conflicting statutes give both sides in a waste case a statute to support their positions. One holds the state engineer can curtail waste only if a senior water right holder makes a call for more water.[1] That gives the division engineer cover to do nothing until a call is placed on the river. But this is contradicted by one of the oldest statutes in Colorado water law, passed in 1876: “During the summer season a person shall not run through his or her irrigating ditch any greater quantity of water than is absolutely necessary for irrigating, domestic, and stock purposes to prevent the wasting and useless discharge and running away of water.”[2]

That is how the legislature used to write statutes, in the same language we speak and understand. The 1876 statute was amended in 2015 for the first time to provide that a “ditch system may use a tail ditch to return water to the stream in variable amounts as necessary to facilitate efficient operation of the ditch and delivery of water to persons served by the ditch.”[3] The 2015 amendment justifies carrying more tailwater down the ditch and will likely make it harder for a state engineer to allege that “push water” is excessive.

In 2014 a state official, after being notified by an attorney for a landowner with property under the Meeker Ditch, told the Meeker Townsite Ditch Co. that it was diverting too much water into the ditch, and spilling too much water out of it – well beyond a conceptual “duty of water.” Brent Gardner-Smith has who covered local, state and regional water issues for Aspen Journalism for over aa decade, wrote an article in 2016 about wasting water on the Western Slope that was also published in the Aspen Daily News. [4] It was entitled “Don’t take more than you need: wrangling water on the Western Slope.”

Erin Light, the division engineer in Division Six, said the ditch company’s historic water right of nearly 30 cfs was enough water to irrigate 1,000 acres, far more than the 153 acres of hay being irrigated, which a hydraulic engineer had recently said required just 6 cfs. When Light ordered the ditch operators to divert less than the 20 cfs of water they had been, they challenged her, saying she could only do that if a call was placed on the river by a senior irrigator, which had not been done. They also asked her to put her curtailment order in writing, which she did. The order informed the ditch operators that “Colorado statue clearly prohibits the running of water not needed for beneficial use.” And Light cited the 1876 statute on waste.

The ditch owners appealed Light’s order, but the Colorado attorney general backed her saying a division engineer can curtail waste at any time, whether or not a river was “under administration”—waterspeak for when a call is placed on the river.[5] Light seems to be the one division engineer on the Western Slope calling out ditch owners for waste. Her territory includes the Yampa, White, and North Platte river basins in the northwest corner of the state.

“I would say I’m more telling than I am curtailing,” Light, who has been the division engineer in Steamboat Springs since 2006, told Aspen Journalism. “I can go out to a piece of land and say, ‘Oh my gosh, you’ve got six inches of water on this land. There are ducks swimming around. This is wasteful.’” Light was also quoted as saying, “You can go to the landowner or the irrigator and say, ‘This is waste,’ and they’ll stare you right in the face and say, ‘The hell it is.’”

Light’s office informed rancher and irrigator Doug Monger in 2016 that water was being wasted in the irrigation system he manages on his Yampa River Ranch three miles east of Hayden. At the time, Monger was a former Routt County Commissioner, a member of the Yampa-White-Green roundtable, and a director on the Colorado River District’s board. You can’t get more connected in Western Slope water circles than that. When asked about the waste, Monger told Aspen Journalism, “I don’t know what the hell difference it makes if I’m wasting water or not, it’s going back in the river. Who the hell cares, if it’s a free river.” (A free river is one that is not subject to a call, meaning anyone can take whatever water they want out of the river, as long as they are putting it to a beneficial use.)

After initially concurring with division engineer Light that he needed to change his diversions, Monger backtracked. “I won’t acknowledge it. And if they start coming up with some scenario on it, we can always get our attorney. “ That was the same reaction that David Smith, the primary shareholder on the Meeker Ditch, had when Light curtailed his ditch in 2014. But after spending $40,000 in legal and engineering fees, Smith has come around to see Light’s point. “I’ve had some disagreements with her, but Erin is an intelligent gal,” he said of Light, who has a master’s degree in civil engineering from Colorado State University with an emphasis in hydraulics and hydrology.

In his last significant act before stepping down in 2017, then State Engineer Dick Wolfe signed an official state report entitled “Internal Guide to Understanding ‘Waste’ and the Determination of ‘Waste’ Associated with Irrigation, as that Term is Used in the Definition of Beneficial Use.” The document shocked me, and likely others, since it was the first time the state admitted what we all know is true, that water diversion practices purposely deplete rivers in the name of “use it or lose it.” The report acknowledges that “someone may choose to divert more water than they can beneficially use for the sole purpose of maintaining a record of higher diversions.” But it then states, “there is a misperception by some that by maximizing the amount of water diverted, regardless of the need, one can enhance or preserve the magnitude and value of a water right in a future transfer or protect it from some other reduction such as through an abandonment proceeding.” It goes on to state that “the plants can only consume a finite amount of water [and] any amount diverted in excess of what is required . . . should be recorded as unauthorized diversions to be excluded from any historical use analysis …. diverting more water than can be beneficially used … will generally be considered a wasteful practice.”

So, when I say that many irrigators are over-diverting to increase the future potential value of their water right, and thus their land, please know that an esteemed state engineer is here saying the exact same thing.

Wolfe clarifies in his guidelines that “the value of a water right is based on its priority and its historical consumptive use,” not the amount diverted. He also cited a statute, CRS 37-92-502, that says “each division engineer shall order the total or partial discontinuance of any diversion in his division to the extent that the water being diverted is not necessary for application to a beneficial use.” And he cites 37-92-103(4), which states that “beneficial use means the use of that amount of water that is reasonable and appropriate under reasonably efficient practices to accomplish without waste the purpose for which the appropriation is lawfully made.” Of course, “reasonably efficient practices” are not defined, and that, in essence, is what I’m trying to change with this book: we need a new standard of what is “reasonably efficient.”

Wolfe also stated in his official “internal guide” that “when the amount of water diverted is not necessary for its conveyance and application to beneficial use, the result is wasting of water.” Please note, extra water diverted does not magically become part of a “return flow” that benefits the river, or adjacent riparian habitat, and extra water diverted is not beneficial because it forms ponds on fields used by migrating waterfowl. It is waste under Colorado water law, pure and simple. “Ultimately,” the report concludes, “diverting more water than can be beneficially used to avoid abandonment . . . will generally be considered a wasteful practice.”[6]

Considered, perhaps, but likely not acted upon.

Waterfowl have now become a common excuse for diverting too much water, since ducks and other migrating birds will inevitably find water pooling on lands next to rivers. A whole symbiotic relationship has grown up between nonprofits like Ducks Unlimited and irrigators in Colorado, with nonprofits touting the benefits of over-diversion.[7] It is another excuse to keep diverting what we’ve always been diverting, and why some of my water friends tell me to stop rocking the boat.

Larry Meyers was a third year law student in 2016 when he wrote a Comment for the University of Colorado Law Review bemoaning that Colorado, practically alone among all western states, lacks a public interest doctrine.[8] That’s what the Colorado Supreme Court said in 1995 when Arapahoe County attempted to claim 900,000 acre feet from the Gunnison River basin, to be delivered from proposed Union Park Reservoir in the Gunnison Basin across the Arkansas Basin and ultimately into Antero Reservoir in the South Platte Basin. Robert Brown, the water Division 4 judge deciding the case, held that the most Arapahoe County could claim was 15,000 acre feet, not enough to justify the $1 billion price tag, so he denied Arapahoe County’s water application in 1998 “with prejudice.”[9]

In fighting the water grab, environmental groups claimed that the Union Park Project would adversely affect the public interest—that is, fisheries and wildlife habitat, recreation, water quality, and the Gunnison Basin’s economy, property values, and its general quality of life. The Colorado Supreme Court wasted no time in dismissing these claims as superfluous, saying “conceptually, a public interest theory is in conflict with the doctrine of prior appropriation.”[10]  Myers believes a sane public interest doctrine would permit the court to hold that a water application is against the public interest if it would substantially impair a stream’s riparian ecosystem, if it impaired water-reliant economies or property values, and if it does not provide a greater benefit to the local economy than the value of the interests that are harmed.

Yes, this may sound naïve, but remember that most states have a public interest doctrine that lets them make this analysis. That’s what courts are for, aren’t they? Most states let water engineers or commissioners consider water right applications, unlike Colorado which, standing alone, leaves this decision solely to a water court that must restrict its review to whether the application violates the prior appropriation doctrine.

Consider Alaska, which permits the water commissioner to weigh the benefit to the applicant against the impact to the community. In addition to considering whether a prior appropriator will be affected, the commissioner can analyze the proposed water right’s effect on fish and game resources or recreational opportunities, how it effects public health or harms other persons, the ability of the applicant to complete the appropriation, and the effect upon access to navigable or public water.[11] Alaska became a state in 1959, exactly 100 years after gold was discovered in Central City and the foundations of Colorado prior appropriation law were formulated. I conclude that Alaska learned something from 100 years of Colorado history.

When the U.S. Supreme Court has been asked to resolve interstate water disputes, it ends up deciding the cases based on equitable apportionment, which is a fairness doctrine.[12] The oldest water right in Colorado is what is now known as the People's Ditch, an acequia ditch in the San Luis Valley which apportions water in the ditch based on water supply—in times of shortage, everyone on the ditch shares the shortage. Colorado’s strict prior appropriation doctrine is one of several different methods of apportioning water; it provides certainty, but it is not the only method of apportioning water.

For decades, environmentalists have claimed we can leave more in the river if we just use water more efficiently. But irrigation efficiency is endlessly controversial and usually described in zero-sum terms, where one person’s savings is criticized as another’s loss.[13] When I searched for “Open ET” in in the Colorado Water Plan, the revolutionary website that estimates irrigation consumption on every field in the West, I got zero results. It doesn’t exist. As far as the Plan is concerned, irrigation efficiency doesn’t exist either. Irrigators fear that any reduction in the amount they divert will drop the future potential value of their water rights. Legally, the water right is the water that plants consume over a growing season. It should be a simple matter of multiplying the acres being irrigated by 2 acre-feet, the amount that most agree hay consumes over an irrigation season. But water courts in Colorado permit endless speculation about how big a water right is—and the more an irrigator starts with, the more an irrigator can transfer. In practice, Colorado water law incentivizes irrigators to divert the maximum amount possible from the river, so that’s what they do. Then their lawyers and engineers take over to make their water right appear as robust as possible.

Agricultural water reform involves both improving irrigation infrastructure and also reforming Colorado water law so that irrigators are given incentives to use less instead of more. We start with the science. Scientists estimate water consumption by doing a “mass balance analysis,” where water consumption is the difference between the amount of water that is diverted from a river to a field and the amount that comes back to the river, either through the tail race at the end of the irrigation ditch or in delayed underground return flows. Consumption can be by crops, or it can also be by phreatophytes, a Greek-origin word describing plants with long taproots that drink water without producing a crop deemed beneficial.[14] In Colorado, the most common phreatophytes are cottonwoods, willow, Russian olive, and tamarisk. Plants consume the same amount of water whether they are flood irrigated or sprinklered, assuming they can drink to their heart’s content. People who support irrigation efficiency say nothing changes if irrigation systems are efficient because plants consume the same amount of water no matter how you irrigate them. And opponents of efficient irrigation systems say that consumption goes up when water is delivered more efficiently because crops consume more.

Irrigation efficiency generally refers to how water is delivered to the plants. Traditional irrigation practice in Colorado involved piling up some rocks in the river to divert water into a hand-dug ditch that courses along a hillside and lets water spill onto the field below. Water is measured, often imprecisely or not at all, in flumes placed in ditches dug in the 1800s. Flood irrigation is inefficient—it waters fields unevenly since water flows around the high spots. As long as there is no call on the river, there is no limit to how much water can be diverted from the river, as long as it is applied to a beneficial use, without waste. Flood irrigation is used on 91 percent of Western Slope irrigated acreage, compared to 42 percent on the east slope and only 3 percent in the Republican River basin where water is scarce.[15]

Irrigators in Colorado also have a transparency issue, in that they are loath to discuss in public how they are using their water and the status of their irrigation systems.

Consider that in 2015 the Colorado Roundtable provided a grant to a Glenwood Springs engineering company to survey irrigation ditches in the Eagle County Conservation District. Colorado is divided into 79 such districts, each administered by the Natural Resources Conservation Service, a USDA program. The Eagle County Conservation District includes terrain extending southward from the Colorado River and I-70 down to Brush Creek, south of Eagle, and extending westward from Vail Pass to Glenwood Canyon. There are 500 ditches in the district, and the Colorado Roundtable grant provided enough money to survey twenty-five of them, 5 percent of the total.

Erin Jaynes, a recent geography graduate with a specialty in GIS mapping, met the landowners, walked the ditches, and prepared a report. On September 26, 2016, she showed photographs to the roundtable of what she had found. One photo showed a headgate leaning over, at risk of completely detaching and falling into the river. A headgate is where water is taken from the stream; when closed, all water remains in the stream. Many headgates divert all water from streams, particularly small tributary streams. If they remain open when it is not necessary to irrigate, they dry up the stream with no benefit. Jaynes identified how repairing a ditch headgate could protect a riparian area by permitting a bypass flow around the headgate to remain in the river. And she showed a large sinkhole next to a ditch, caused by gravel in the soil, a common problem that can be solved by lining the ditch.[16]

Then she showed: a ditch that had filled in with sediment, a problem that can be solved by placing a culvert in the ditch; a ditch that leaked 2 cfs, amounting to 240 acre-feet over a four-month irrigation season; and a measuring flume that was completely underwater, which means it wasn’t measuring anything. That last photo was especially glaring to me, as one huge weakness in Colorado’s water delivery systems is the woeful lack of gages at headgates to measure water diversions.

Richard Vangytenbeek, of Trout Unlimited, once counted 188 gages on the entire Western Slope, an area encompassing 38,499 square miles. There are 39,690 river diversions on the Western Slope, which means there is only one gage for every 201 places we take water out of Western Slope rivers, about one gage for every 200 square miles! When I expressed surprise, Russ George, the former director of the Division of Natural Resources and the “godfather” of the basin roundtables, provided a clue at a Colorado Roundtable meeting in 2016. George described how his father, then 95 and a Rifle rancher his whole life, once confided to him, “Don’t ever let anyone know how much you are diverting. If you do, they’ll accuse you of taking too much and come take it away from you.”

With climate change threatening to raise irrigation demands by 20 percent or more, this kind of thinking will be harder and harder to justify. And it does raise the question: can a person irrigate in public, in a transparent fashion? Today, gages can be put in rivers with far less expense than in the olden days. High tech gages transmit water levels in real time to satellite linkups and can even transmit video so we could potentially see what is happening at a given gage on the stream in real time. But the instinct to keep diversions cards well-hidden definitely shaped how Jaynes approached her report on the status of irrigation ditches in the Eagle County Conservation District.

She found the newer ranchers welcomed her, happy to learn how to improve their irrigation ditches and delivery systems. But many older ranchers refused to participate in the project. Scott Schlosser and Scott Smith joined Jaynes when she presented her findings to the Colorado roundtable. They have been ranching in Eagle County for a long time, and when they introduced Jaynes to the old-time ranchers, they were more likely to participate in the ditch survey. Still, many declined. And when Jaynes prepared maps to identify the ditches she was able to inspect, she left off GPS coordinates so the headgates couldn’t be located. And after sharing her binder of photographs and conclusions at the roundtable meeting she took it home with her, ensuring it was accessible only to the landowners and district officials, and not available to the taxpaying public, who paid for the ditch study via state funding. The Eagle County Conservation District also refused to make the study public.

It’s too bad that it is so hard to talk with irrigators about the status of their delivery systems, how they could be improved, and how they could be paid for. For example, if we spent $100,000 modernizing each of the 59,671 river diversions in the state, the $6 billion cost would amount to just $74 per Colorado resident per year, spread over 20 years.[17] Before recoiling at the cost, remember that $6 billion will be spent employing engineers and construction contractors all over the estate, improving local economies. And with that kind of cost-sharing, the state’s citizens could also help fund a variety of other efficient irrigation practices, such as lining ditches or installing pipes to limit water leaking into the soil. This is rarely done in Colorado because irrigators say it costs too much.

Another efficiency practice out there includes cutting down water-loving phreatophytes that line ditches. But this is also rare, in part because the Colorado Supreme Court has held that a farmer who made his irrigation system more efficient could not use the water that cottonwoods and willows formerly drank.[18] There is no water right in Colorado for saved water, the court reasoned, until the legislature creates it. Forty years later, Colorado legislators have still not addressed this issue, or created an incentive to line ditches. Typically, water is diverted from rivers into irrigation ditches through concrete boxes with a metal gate that is raised or lowered by cranking on an iron wheel. The wheel is often padlocked and stays open for weeks, months, or the entire irrigation season. As a result, much more water is usually diverted through these devices than needed to irrigate fields. But Rubicon flume-gates, invented by an Australian company, use solar power to constantly raise or lower aluminum gates that deliver just the right amount of water needed. Irrigators can adjust the amount of water being delivered with signals sent remotely from their phones. Installing this technology is simple: concrete is poured into a form straddling the ditch and the Rubicon device is dropped into it. It can be done in a day once the concrete is poured. In Colorado, the Rubicon representative has all but pulled up stakes—it is just too hard to make any sales here.

            Sprinklers could also be used much more than they are on the Western Slope. They deliver water uniformly to fields. They generally pay for themselves in labor savings because they avoid the time it takes to meticulously create furrows. Fields don’t have to be perfectly level and field hands don’t have to be on call to flood different sections of a field every couple of hours. Irrigation ditches and turnouts regularly silt up or get clogged with debris, and that requires more attention. Since sprinklers deliver water uniformly, crop yield rises. Evaporation decreases because water does not pool on fields, especially if they are sprinkled in the morning before it gets windy or before the soil heats up later in the day.

Figure 7.1 Irrigation efficiency and water needs

A 100-acre field that is flood irrigated must divert about 400 more acre-feet from the river than if sprinklered. Sprinklers won’t cut back on water consumption—they can save some of the water volume that is consumed in flood irrigation, but the amount is hard to quantify and likely on the order of only a few percent.[19] Sprinklers simply do a better job of getting water to where it is needed. The green circles we see on the ground when flying east from Denver International Airport are created by pivot sprinklers that rotate around a center point. The sprinklers hang from a string of aluminum pipes that typically extend for a quarter mile, the length needed to irrigate a quarter section of land (a section is one square mile, so the four quarter sections are each a half-mile square). Older models have sprinklers mounted above the horizontal pipes and they lose a lot of water to wind and evaporation. You can tell if a sprinkler is modern because the sprinklers hang below the horizontal pipes a couple feet above the ground.

Flood irrigation is hard work, and pivots can save the labor of two to three persons. Since they don’t reach the corners, pivot sprinklers irrigate about 20 percent less of the ground than traditional furrow irrigation. But they deliver water more uniformly, so yields go up. No water pools at the end of the furrows where it can evaporate or pool in tailwater ditches to water thirsty weeds. Sprinklers also save water. “A seven-tower center pivot will use a third to a half less water than what's used in flood irrigation,” Everett Vezain, who sells sprinklers from his shop in Billings in eastern Montana, told The Prairie Star in 2012.[20]

Sprinklers also prevent pollution that results when flood irrigation tail waters carry fertilizer and salts back to the river. Pivot sprinklers are not cheap. A system to irrigate a 160-acre quarter-section costs $100,000 to $150,000, and they take about four-to-five days to install. But they typically pay for themselves in about five years, and most buyers come back to purchase more for their remaining fields. “Every year one of our clients calls us after the season to tell us how his yields are thirty or forty percent better than with flood irrigation,” Vezain told the Prairie Star. On the mountainous Western Slope, side-roll sprinklers move back and forth in a straight line rather than pivoting around a center. And if our goal was to take as little water out of rivers as possible, instead of diverting as much water as historic decrees said we could, we’d use them a lot more.

Beyond labor savings, the real benefit from sprinklers is that far more water can remain in the river. Sprinklers also limit pesticide and fertilizer residues from joining water in tail water ditches, further protecting our rivers. Nitrogen runoff into rivers is one of the primary threats to rivers in the United States, and it shows up on the list of impaired rivers periodically produced by the Colorado Department of Public Health and the Environment.[21] And there are drip systems that generally need 50 percent less water than flood irrigation, and they can save 5-to-10 percent crop water consumption.[22] They are more expensive to install, but they need the least water. In Israel, drip systems irrigate 75 percent of all agriculture.

And there are soil moisture sensors, which avoid watering before necessary and shut down irrigation when water reaches the desired soil depth. It also helps to amend soil with organic matter that holds moisture better and generally produces a greater yield. It also reduces the amount of water that needs to be applied to a field. The typical irrigator on the Western Slope diverts water into a ditch hand-dug more than a century ago, floods it onto his field, and comes back several hours or days later to flood another field. Amending the soil with organic matter is a lot of work and, an irrigator might figure, at the end of the day his water right just decreased because he needs less.

Then there is deficit irrigation, which attempts to save water and get the same crop yield by decreasing water during strategic periods in the plant growth cycle. For alfalfa, applying more water earlier in the season and less water later will increase yield compared to reducing deliveries at the same rate all season long. Unlike most efficient practices, which do not decrease water consumption, deficit irrigation actually reduces water consumption, because less water is being evapotranspirated by the plant leaves into the atmosphere. Plants get water when it is most beneficial in their growth cycle and less at other times.

Figure 7.2 Barriers to irrigation efficiency

Reasons Not To

Perhaps the greatest barrier to efficient irrigation practices is the alleged impact on return flows. Diverters claim that taking water out of Colorado rivers is beneficial because the return flows seep back to the rivers in the fall when they would otherwise run dry. It is the perfect excuse for not changing anything. An engineer is needed to estimate when water flowing underground returns to the river, and each user on the river must hire his own engineer to challenge the other engineers, and at the end of the day it’s just too expensive to change anything. In the only publicly available report I have found that analyzes return flows, the USGS geologist concluded that the return flows coming back into the Colorado River near Parker Arizona were too uncertain to measure.[23] That doesn’t surprise me since how can anyone realistically determine where water spread across acres travels underground, whether it gets lodged in confined pockets, when it returns to the river, and how much it appreciably changes river flows. We just assume it happens.

Due to our pre-occupation with return flows, we might keep using water just like we do today in Colorado forever. Of course, when return flows hit the river is very location specific. In some locations, return flows hit the river within a few hours or days. But very people have had their return flows analyzed, and if they do, there is a range of models to choose from, thus extending debate over them. A 1976 report from the EPA called Assessment of Irrigation Return Flow Models summed up some of the difficulty in measuring return flows by noting that “… when models are applied to systems involving irrigation return flows, errors and unknown variables tend to get lumped together in the groundwater because of the usual lack of groundwater data for verification and/or inadequate definition of subsurface hydrology.” In short, it’s murky down there.[24]

One engineer remarked at a public meeting discussing irrigation efficiency in 2013 that some return flows take sixty years to make it back to the South Platte River. The South Platte dries up repeatedly below Commerce City, only to reappear when return flows restore the river farther downstream. Water readily transmits through gravel and sand left behind by the glaciers along the South Platte River, known as the piedmont. After farmers suck it dry in one location, it reappears downstream. But irrigators who say that return flows help rivers are basing their reasoning on the post-beaver Western landscape. Beaver were trapped throughout North America between 1820 and 1840 until a population estimated as high as 200 million was reduced to as few as 100,000.[25] When re-introduced, beavers dam rivers and hold back water that percolates into the river all year long. It strains credulity to suggest that Colorado rivers dried up completely every year before man came to the rescue in 1860 with his blessed return flows.

In 2023 the Colorado legislature amended Colorado water law to permit stream restoration activities. Another candidate for the “most contentious bill of the session,” it allows minor stream restoration activities including stabilizing the banks and planting trees to cool river temperatures, installing porous structures (including by beaver), reducing the stream surface area, and reconstructing the channel. Permissible stream restoration projects include projects to mitigate for wildfire or flood, provided they do not cause material injury to any vested water right, do not create a new water right, do not affect any existing water or real property rights, or create any unnecessary dam or other obstruction. Commonly referred to as the beaver restoration act, the statute does not mention beaver once, as that would be too controversial.[26]

Another excuse for doing nothing is that water consumption increases when irrigation systems are made more efficient. Irrigators in the Arkansas Basin say we should keep flood irrigating because sprinklers increase water consumption. But they could reduce consumption by irrigating less of the circle, which we see from the airplane whenever less than 360 degrees of the circle is green. These same farmers say that it does not matter how you irrigate because plants consume the same amount of water whether they are flood irrigated or sprinklered. Their claim that efficient irrigation is the problem is a smokescreen—their real concern is how to take as much water as possible, or to be fair, to divert as much water as they see as being necessary, from the river or groundwater, without interference.

Another excuse by Arkansas Valley farmers to resist installing efficient sprinkler irrigation systems is their claiming that if they do, Kansas will complain they’re interfering with the Colorado-Kansas Arkansas River compact. But that interference occurred because Arkansas basin farmers drilled over three thousand additional wells after the Colorado-Kansas Water Compact was signed in 1949. The Arkansas River is governed by the 1949 Arkansas River Compact, which requires Colorado to keep delivering the same volume of water to the Kansas state line as existed in 1948. After 1949, Arkansas Basin irrigators in Colorado drilled 3,000 high capacity wells, claiming they did not know that groundwater pumping would affect Arkansas River flows. That is disingenuous since the Arkansas River is a gaining river—it loses water in some places only to gain it further downstream, a phenomenon that can only be explained by varying groundwater levels. It’s not until the Arkansas River gets past the 100th Meridian, near Dodge City, Kansas, that it has a consistent flow of water. Settlers have observed and known this for 150 years.

The 1949 Compact did not prevent Colorado irrigators from drilling more wells, it just required Colorado to keep delivering the same amount of water in the Arkansas River to the state line as existed in 1948. That wasn’t happening so Kansas sued Colorado in 1985 in the U.S. Supreme Court. The court appointed a special master who determined that the increase in groundwater pumping since 1948 had caused serious depletions at the state line—from 1950 to 1996, the depletions amounted to 428,005 acre feet, and Colorado was fined nearly $35 million. That expense was borne by all taxpayers in Colorado, not just the over-pumpers. Since then, Colorado has curtailed the groundwater pumping and been in compliance with the Compact.[27]

When I recommend that irrigators in the Arkansas Basin use sprinklers because they deliver water more efficiently than flood irrigation, I keep hearing the same refrain—sprinklers cause consumption to increase and Colorado will violate the Arkansas River Compact. That’s not true—irrigators can shorten the amount of the circle they irrigate to hold down consumption—but it’s trotted out as one more reason to avoid change. The USDA asked Colorado farmers in its 2012 census why they were reluctant to make irrigation efficiency improvements.[28] Their top concern was uncertainty about water supplies—why go to the expense of making irrigation efficient if they won’t get water in low flow years? In part, this is because rain and snowfall vary so much from year to year. But another reason is because it’s so hard to transfer water from one farm to another. If farmers could trade water it could be transferred to where it is most valuable. But transferring water to the farm next door takes a water court change case, and that is too expensive and risky to justify.

Colorado, the only state where courts alone decide water disputes, is in a class by itself. Cadillac Desert author Marc Reisner said in 1990 that Colorado “is notorious for freighting ‘the right of free transferability’ with the West’s most time-consuming and expensive process, which one economist described as ‘a needlessly costly and uncertain system in which innovation is difficult.’ ”[29] That’s putting it charitably. Walmart, the nation’s largest grocer, gets much of its cost savings from reduced transportation costs.[30] It tries to achieve shipping savings by contracting with local farmers to grow vegetables and other crops in supplies large enough to meet Walmart’s local demand. For this market to work, farmers have to be able to readily switch crop types. But in Colorado, farmers must think twice before they contract with Walmart to grow a different crop. While changing the crop type does not necessitate a water court change case, any change in crop that results in lower consumptive use could haunt water rights holders who later sell their water right, which will be calculated on their historic consumptive use. If a farmer switches to a lower consumptive use crop, say from alfalfa to corn, other farmers will divert the water that is no longer being consumed. The farmer who switched to corn will have lower historic consumptive use, or HCU, and over time that reduced use could mean the farmer has less water to sell down the road.[31]

Nearly every other reason irrigators give to explain their reluctance to adopt irrigation efficiency improvements to their physical system is that the additional revenue will not justify the costs. But the Natural Resource Conservation Service and other government subsidies will pay for 65-to-80 percent of the cost of irrigation improvements in Colorado. If irrigators are telling us that irrigation efficiency improvements are still not worth it, maybe the problem is that farming and hay-growing is too marginal here. But irrigating is the only way to prove up, and maintain, water rights within Colorado’s “use it or lose it” system. We can change this by guaranteeing a landowner’s water right by multiplying the acres irrigated by 2 acre feet per year.

At a 2014 legal education seminar for real estate lawyers, an attorney on one panel said, “I don’t know much about water rights, but I know enough to talk with water engineers. They say if you do not use all of your water rights, you’ll lose them.”[32] There it is. All this talk about return flows and consumption going up with more efficient irrigation systems is nonsense. The real issue is making your water right appear as robust as possible, and you do that by taking the maximum water possible out of the stream all summer long.

As such, a thorny question in Colorado is asking just how much water is needed to irrigate a crop. Historically, the only question a 19th century Colorado water judge asked was how much water was being diverted to irrigate a field, measured in cubic feet per second. The judge did not care how efficient the field or the ditches were; he only wanted to know how much was being diverted. But how much water a crop needs on a given day depends on several factors: temperature, humidity, hours of daylight, wind speed, and how far along the crop is in its growth cycle.

Transpiration—the rate that water goes through a plant and into the atmosphere—can be measured several ways. The best way is through lysimeters, plots of earth segregated from the surrounding soil and suspended in a box. By comparing the water added to the lysimeter to the water draining out the bottom, lysimeters accurately measure evapotranspiration. They’re expensive to build and monitor, but enough have been constructed that engineers have developed coefficients that can estimate crop water consumption based on the crop, elevation above sea level, time of year, temperature, and crop growth stage. Agricultural scientists at land grant universities develop the coefficients by growing crops and measuring how much water they need. Mathematical coefficients can be hard to grasp for lay persons, but water engineers can readily use them to figure out how much water crops need. They are simple, reproducible, relatively accurate, and apply across different locations and climates.[33]

Crops tend to consume similar amounts of water no matter where the fields are in Colorado, and we have developed coefficients that account for the geographic variation we do have here. Nearly all water is used to grow three crops in Colorado: hay, alfalfa, and corn. Once we know how much water that hay or corn need over a growing season, we could multiply the irrigated acreage by the crop coefficients and know the consumptive use. Corn requires about an inch of water a week, and most corn varieties are harvested about ten-to-thirteen weeks after planting.[34] And as with corn, we know how much water it takes to grow hay. The coefficient for pasture grass in Colorado is about two. Engineers can determine the annual crop water need of a hayfield in acre-feet by multiplying the number of acres by two. A field with 100 acres needs 200 acre-feet of water. Another rule of thumb is that 1 cfs is needed to irrigate forty acres over the course of a summer. One cfs generates nearly 2 acre-feet each day, meaning one cfs running continually for 24 hours would deposit two feet of water on an acre.[35] Thus, 40 cfs diverted from a river over the course of an irrigation season (not constantly, but cumulatively in batches that total up to only 24 hours over an irrigation season) would be enough to adequately irrigate forty acres growing hay. On average.

That last phrase is a gotcha, and there’s no limit to the amount of money that can be spent estimating crop water consumption on a particular field in Colorado. Astoundingly, fifty different methods have been developed to measure water consumption![36]

Another source of endless conflict is the specific soil composition of ditches or the fields they irrigate. While 2.5 cfs is generally needed to irrigate 100 acres of pasture grass (at 40 acres per 1 cfs), the Carbon Creek Ditch near Ohio Creek in the Gunnison Basin needs ten cfs to irrigate 100 acres, four times more. The 1938 water court case adjudicating the claim explains why. “The ditch is approximately 1 mile long, and is constructed largely through decomposed granite. The topsoil is thin and sandy with a high degree of porosity and is underlain by deposits of gravel and cobblestone, all of which causes the water to sink into the soil very rapidly.”[37] In this example, 75 percent of the water diverted from Carbon Creek could be kept in the river by lining the ditch. This is as simple as laying a felt liner on the ditch bed and spraying it with a polyurethane coating to make it impermeable. The 1938 claimant then touted the benefits of return flows, saying that the water leaking into the porous soil “return[s] to the river for use by appropriators lower down.”

The Gunnison Roundtable cites this case in its 2014 basin implementation plan, not to call for increased efficiency such as by lining the porous ditch, but to illustrate why the irrigation requirements are so great in the Gunnison Basin, where 97 percent of the water diverted from rivers is for irrigation.[38] It is all but certain that a court today would approve this claim for four times the water typically needed, just as the court did eighty years ago. Ironically, crop productivity has never been a factor in determining water rights in Colorado, then or now. This anomaly is illustrated when we consider elevation. Crops consume more water at higher elevations where the air is dryer, and fields are less productive. The amount of water that pasture grass consumes was measured at nine stations in the Colorado high country, three in South Park, and six on the Western Slope. While there’s significant variation, the trend is unmistakable—as elevation increases, so does water consumption.[39]

 Meanwhile, hay production drops since temperatures are colder and growing seasons are shorter. But in Colorado that’s not a reason to divert less, it’s a reason to divert more! The less efficient your ditch and the less productive your field, the more you get to divert from a stream! The system rewards excess and punishes conservation. It generally takes about 6-to-7 inches of water to grow a ton of alfalfa, and the relationship is linear: the more water is applied, the more alfalfa grows. An acre that receives 6 inches of irrigation will produce about a ton, while an acre that receives 24 inches will produce about 4 tons.[40] 

Irrigators typically get one-to-two alfalfa cuttings a year in Colorado, and the first is typically the most productive since it relies on higher soil moisture carried over from fall rains and winter snowmelt. Farmers and ranchers get more cuttings at lower elevations, while high elevations may yield only one cutting.

Figure 7.3 Pasture water consumption at higher elevation

By contrast, California gets six-to-seven alfalfa cuttings per year, and the Imperial Valley, where it only rains three inches a year, can get up to twelve cuttings a year, all of it irrigated with Colorado River water, most of it from, you guessed it, Colorado.[41]

Surface flooding generally deposits about three-to-four inches of water per irrigation, while pivot sprinklers typically deposit only an half inch to an inch. In most soils, about one inch is applied as the center pivot revolves around the circle. That minimizes surface runoff and prevents excess wheel track rutting. If soil moisture drops below 50 percent, the alfalfa can be so damaged that later over-watering cannot bring it back that season. Agronomists at land grant universities are studying deficit irrigation practices to see how plants can maximize yield on lower irrigation budgets. Alfalfa plants can die if they go sixty days without water, so ceasing irrigation entirely by transferring water to another field will likely cause permanent damage. More irrigation early in the season coupled with less during the summer may also be better than reducing irrigation at the same rate all season long.[42] In Colorado, alfalfa and hay production have been declining as “gentlemen ranchers” buy out farms and stop producing hay for resale, and as cities purchase irrigation rights.

Figures 7.4 Sprinkler use in Colorado

            As I’ve said before, I am not an irrigator. And I know irrigators, i.e., farmers and ranchers, hate hearing “you’re doing it wrong” from people like me. But I do think it is fair to point to best management practices when it comes to irrigation, and it is a fair question for the general public to ask whether the public’s water is being applied in a manner consistent with published best practices. Consider this list of the top 16 BMPs from a 1994 publication from Colorado State University and Northern Water called Best Management Practices for Irrigated Agriculture: A Guide for Colorado Producers. Experienced irrigators, to be fair, probably understand this list quite well, while non-irrigators may not. If nothing else, it does show non-irrigators like me how much goes into irrigating a field the right way.[43]And as the report states, “Experienced producers know how long it takes them to get water across their field and are proficient in avoiding crop stress during years of average rainfall. The difficulty lies in applying only enough water to fill the effective root zone without unnecessary deep percolation or runoff.”

1.     Schedule irrigation according to crop ET, soil water depletion, and water availability; accounting for precipitation and chemigation.” (Chemigation is the application of agrochemicals to soil or crops through an irrigation system.);

2.     Contact a qualified professional to help schedule irrigation and improve the management of your irrigation system if you need assistance.

3.     Determine soil type in each field and monitor soil moisture by the feel method, tensiometers, resistance blocks, or other acceptable methods.

4.     Time irrigations to individual crop needs to eliminate unnecessary applications.

5.     Determine the relative leaching potential of your particular soil and site. Producers should employ all appropriate BMPs on fields with severe leaching hazard.

6.     Install improved irrigation systems where feasible to increase application efficiency and uniformity.

7.     Minimize deep percolation on surface irrigated fields by installing surge flow systems where feasible.

8.     Line irrigation water delivery ditches and install pipelines to convey irrigation water to reduce seepage losses.

9.     Divert and capture irrigation runoff into reuse systems where feasible.

10.  Install sprinkler systems on surface irrigated fields with severe leaching potential where feasible.

11.  Monitor the amount and uniformity water applied.

12.  Maintain sufficient surface residue to reduce overland water flow and increase water intake rate.

13.  Adjust irrigation run distance to maximize irrigation efficiency.

14.  Minimize irrigation runoff through the use of land leveling, blocked end furrows, and border systems.

15.  Alternate irrigated furrows and N fertilize placement on soils with severe leaching potential to reduce nitrate leaching to groundwater.

16.  Adjust irrigation application rate and set time for soil conditions to achieve greater uniformity.

You get the idea. It’s not easy to irrigate with a high efficiency level. And there are another 37 BMPs listed. But if something is worth doing, it’s worth doing right. As the report puts it, “The goal of BMPs is to protect Colorado water resources from degradation, while maintaining the economic viability of Colorado agriculture and related industries.” Works for me.

            And if you think that nothing will ever change the contentious and expensive way that we evaluate water rights, or regulate water use, consider a new website called OpenET. Thanks to satellite-based evapotranspiration data (the “ET” in OpenET), the public can now access how much water is consumed at field scale for millions of individual fields or at the original quarter-acre resolution of the satellite data.[44] OpenET is a collaboration between the USDA, USGS, NASA, the University of Idaho, University of Wisconsin, the Environmental Defense Fund and others. Like Google Earth, users can drill down to individual irrigated fields and determine how much water is consumed over a growing season, field by field. It is revolutionary and answers the question that has retarded any meaningful change to water law for the past 150 years: how much water is consumed on a field?

We have known how much is diverted each year over this time because we have maintained diversion records, albeit in varying degrees of accuracy, as most diversion records are self-reported by the diverter. But we are now in the position of knowing how much water is consumed, and by simple subtraction, how much of the diversion is consumed by the plants in the field (or needed to overcome aspects of the physical irrigation system, leaky ditches, say, or propel sufficient “push water” to the end of the system. With OpenET, Colorado no longer has any excuse for saying it is too difficult to determine how much water is consumed by a given irrigated field. And in my deeply-held view, with every field that we irrigate with sprinklers we can leave more water in the river. Yes, we must also convert to more efficient irrigation systems, but that is a discussion that we can now meaningfully have.

The stage is set to reduce the amount we divert from rivers, for the first time since we began diverting water from Colorado rivers in the 1860s. I estimate that we could leave 40 percent or more of the water we divert in the river if we went all-in for efficient sprinkler irrigation. We could also choose some representative basins, like the Crystal River, to test this. It is now up to us to find the political will to do so.

Figures

Figure 7.1 Irrigation efficiency and water need

Figure 7.2 Barriers to making irrigation efficiency

Figure 7.3 Pasture water consumption at higher elevation

Figures 7.4 Sprinkler use in Colorado

Notes

[1] The SEO or division engineers can order the partial or total discontinuance of a diversion if waste is occurring, "but no such discontinuance shall be ordered unless the diversion is causing or will cause material injury to such water rights having senior priorities.” CRS § 37-92-502(2)(a).

[2] CRS § 37-84-108(1). Also see CRS § 37-84-125, Receipt of too much water, which provides that an irrigator who takes too much water from the river at the headgate is liable to other ditch owners if they can prove they suffer damages from the reduced water, together with attorney fees.

[3] SB15-055, sponsored by Sen. Hodge (D-Sen. Dist. 25, eastern Adams County), Rep. Arndt (D-HD 53, Larimer County), and Rep. Becker J (R-HD 65, Yuma County); http://www.leg.state.co.us/clics/clics2015a/csl.nsf/fsbillcont3/D6A82DE7C5E6773687257D90007823BA?Open&file=055_enr.pdf.

[4] Gardner-Smith, B., “Don’t take more than you need: wrangling wasted water on the Western Slope,” July 24, 2016, Aspen Journalism, http://aspenjournalism.org/2016/07/24/dont-take-more-than-you-need-wasting-water-on-the-western-slope/.

[5] In the Matter of a Petition for an Appeal of Certain Orders of the Division Engineer in Water Division No. 6 Concerning the Meeker Townsite Ditch, Respondent/Appellee Division 6 Engineer’s Answer, Oct. 16, 2014, Colorado assistant attorney general Philip Lopez.

[6] Wolfe, D., “Internal Guide to Understanding “Waste” and the Determination of “Waste” Associated with Irrigation, as that Term is Used in the Definition of Beneficial Use,” June 30, 2017, Colorado Dept. of Water Resources, pg. 4.

[7] The Colorado Water Plan’s discussion of the Rio Grande Basin states that the diversion of water is “especially important for waterfowl and big game.” CWCB, Colorado Water Plan, 2022, pg. 114. The 2022 South Platte Basin Implementation Plan, Volume 1, states on page 73 that the “Creation of alluvial recharge basins for agricultural augmentation plans can also provide waterfowl habitat and hunting opportunities.” See Volume 2, pages 146-155 for examples of wetlands that have been created for waterfowl.

[8] Myers, L., “To Have Our Water and Use It Too: Why Colorado Water Law Needs a Public Interest Doctrine,” University of Colorado Law Review, Vol. 87, 1041-1106, 2016. Footnote 7, reproduced verbatim from the 2016 Comment, lists the state statutes that embody the public interest doctrine: ALASKA STAT. § 46.15.080(b) (2015); ARIZ. REV. STAT. § 45-155(A)

(2015); CAL. WATER CODE § 1255 (2015); IDAHO CODE § 42-203A(5)(e) (2015);

MONT. CODE § 85-1-101(6) (2015); N.M. STAT. § 72-5-5.1 (2015) (“public welfare”);

NEV. REV. STAT. § 533.370(2) (2015); OR. REV. STAT. § 196.805 (2015); UTAH CODE

§ 73-3-11 (2015); WASH. REV. CODE § 90.54.020(3) (2015). See also TEX. WATER

CODE ANN. §§ 11.121, 5.271 (2014) (creating a statutory scheme that requires

promotion of public interest in most water permitting applications). These states

and their respective public interest standards represent every state entirely west

of the hundredth meridian except Hawaii, [Wyoming,] and Colorado.

[9] Application for Water rights by the Board of County Commissioners for Arapahoe County for the Union Park Reservoir Project Phase I on Water Availability, Case No. 88-CW-178, decided April 6, 1998., pg. 89.

[10] Bd. of Cty. Comm’rs of the County of Arapahoe v. United States, 891 P.2d 952, 971–73 (Colo. 1995) noting that “a public interest theory is in conflict with the doctrine of prior appropriation because a water court cannot, in the absence of statutory authority, deny a legitimate appropriation based on public policy.”

[11] ALASKA STAT. § 46.15.080(b) (2015).

[12] In Colorado v. New Mexico, 459 U. S. 176, 183 (1982), the US Supreme Court held, “The doctrine of equitable apportionment aims to produce a fair allocation of a shared water resource between two or more States.” In Nebraska v. Wyoming, 325 U. S. 589 (1945) the US Supreme Court divided water in the North Platte based on equitable apportionment. In Kansas v. Colorado, 206 U.S. 46 (1907), the US Supreme Court held that “the substantial interests of Kansas are being injured to the extent of destroying the equitable apportionment of benefits between the two states.” In fact, the court did not find that Colorado’s use of the Arkansas was inequitable in 1907. In Arizona v. California, 373 U.S. 546 (1963), the court held, “The doctrine of equitable apportionment should not be used to divide the water between the Indians and the other people in the State of Arizona.” Page 373 U. S. 597. Rather, the court held that water should be reserved to the Indian tribes under the Winters doctrine, which holds that when the United States carved out reservations for Indian tribes, it reserved water needed to make the lands habitable. But the US Supreme Court in Arizona v. California affirmed the equitable apportionment doctrine because it said the US congress “passed, an Act on August 19, 1921, giving the States consent to negotiate and enter into a compact for the "equitable division and apportionment . . . of the water supply of the Colorado River." Page 373 U.S. 557.

[13] “Water use efficiency (WUE) is defined as the crop yield per unit of water use. But WUE can be increased by reallocating water to its highest use. The last item is strongly linked to societal aspects affecting water use and regulations. Without careful management, irrigated agriculture has been detrimental to the environment and has endangered sustainability.” For a discussion of irrigation efficiency, see Howell, T., “Enhancing water use efficiency in irrigated agriculture,” 2001, Agronomy Journal, Vol. 93, No. 2, 281-289.

[14] The term was coined 100 years ago when electricity enabled groundwater pumping around the world. “Phreatophyte,” Dictionary.com, http://dictionary.reference.com/browse/phreatophyte.

[15] The Colorado Department of Local Affairs reports how many acres are sprinklered or flood irrigated by county and their assessed property value. 2013 Department of Local Affairs (DOLA) Annual Report to the Governor and Legislature, pg. 142-145.

[16] Colorado River basin roundtable meeting Sep. 26, 2016.

[17] At $100,000 per ditch diversion structure, it would cost $5.97 billion to modernize every one of the 59,671 diversion structures in Colorado. Added to the $1.87 billion cost to sprinkler 1,245,581 acres at $1,500 per acre, the $7.84 billion total cost amounts to $97 per year for each of Colorado’s 5.45 million residents amortized at 3 percent over 20 years. If this cost was spread only among Colorado tax returns reporting above-median income, it would amount to $376 per return per year for 20 years. Historically, the Natural Resource Conservation Service has paid up to 65 percent of this cost.

[18] Southeastern Colo. W. C. Dist. V. Shelton Farms, Inc., 529 P.2d 1321 (Colo. 1974). Justice Groves initially planned to dissent from the court majority’s conclusion that saved water could not be beneficially used. Instead, he wrote a concurring opinion, stating, “I wish to state, however, that, if the General Assembly does not act within a reasonable time in this area, I hope that the matter will be brought to this Court again.” Over 40 years later, the issue has still not been before the court, nor has the General Assembly taken up the issue.

[19] Technical concepts related to conservation of irrigation ad rainwater in agricultural systems, A. J. Clemmens, R. G. Allen, C.M. Burt, Water Resources Research, Vol. 44, 2008, Section 2.2.

[20] Center pivot irrigation more efficient, labor-saving than flood irrigation, by Marty Mull, The Prairie Star, January 14, 2012.

[21] 2025 NPS Basins of Focus Proposal Priorities, Regulation 33: Upper Colorado and North Platte River Basin, lists nitrite pollution on the Blue River and Willow Creek. Selenium is the most commonly cited Nonpoint Source NPS pollutant in the report; E. coli and sediment are also reported. Nonpoint refers to pollutants that come from diffuse sources like sheeting off the land rather than from a single source like a pipe.

[22] Id at footnote 4 above.

[23] Leake S.A., “A Method for Estimating Ground-Water Return Flow to the Colorado River in the Parker Area, Arizona and California,” USGS Water-Resources Investigations Report 84-4229 prepared in cooperation with the US Bureau of Reclamation,, September 1984, pg. 29.

[24] Walker, Wynn R. Assessment of Irrigation Return Flow Models. Oklahoma: EPA, Oct. 1976, pg. 31.

[25] No one really knows how many beaver were in North America, and estimates range from 60 million to 200 million. It’s safe to say they populated every river in Colorado. See Dolin, E., 2010, Fur, Fortune and Empire, pg. 17, W. W. Norton & Co.

[26] Senate Bill 23-270, Concerning Activities that Restore the Environmental Health of Natural Stream Systems without Administration, enacting new CRS 37-92-602(9).

[27] Arkansas Basin Implementation Plan Volume 2, January 2022, pgs. 19-22.

[28] USDA 2012 Agricultural Census, Table 25. Barriers to Making Improvements to Reduce Energy Use or Conserve Water: 2013. 7,525 irrigators participated in the survey out of The USDA interviewed.

[29] Reisner, M., 1990, Overtapped Oasis, pg. 69, Island Press, quoting Tregarthen, T., “Water in Colorado: Fear and Loathing in the Marketplace,” in Water Rights: Scarce Resource Allocation, Bureaucracy and the Environment, ed. R. Anderson (Pacific Institute for Public Policy Research, 1983), pgs. 119-136.

[30] Mitchell, C., “Can a Sustainable Walmart Change the World?,” Oct. 18, 2010, Food Safety News, http://www.foodsafetynews.com/2010/10/wal-mart-announces-global-sustainability-initiative/#.VRAAAEjfMXw.  Walmart hopes to make its grocer business more sustainable. The food-miles debate is not settled, as economists say that shipping foods long distances to a single supermarket can result in fewer transportation miles per pound of food purchased compared to consumers who drive to multiple farmers’ markets to obtain their food.

[31] Synopsis of Colorado Water Law, Colorado Division of Water Resources, 2011, pg. 20. The Current Water Court Rules on the Colorado Judicial Branch Water Courts Homepage, pages 34-35, list the crop type as an important fact to be considered in water court applications; https://www.courts.state.co.us/userfiles/file/Court_Probation/Water_Courts/WaterCourtRulesCorrected_2014_Full_set_of_CRCP_and_Water_Rules.pdf.

[32] Teresa Kerrigan, Esq., President, Raw Land Solutions, LLC, Arvada Co, July 11, 2014, Colorado Bar Association 32nd Annual Real Estate Symposium, Vail.

[33] Design and Operation of Farm Irrigation Systems, 2d Ed., Chapter 8, Water Requirements, p. 208-209, 2007, American Society of Agricultural and Biological Engineers, ASABE publ.

[34] Corn: A Growing Guide, http://www.rodalesorganiclife.com/garden/corn-growing-guide.

[35] In fact, 1 cfs delivers 1.98 acre-feet in 24 hours, or 724 acre-feet over 365 days.

[36] Procedures for Estimating Evapotranspiration, University of Wyoming Water Resources Data System Library, Chapter 4.

[37] The quoted language was slightly altered to eliminate hard-to-follow legalese. See the “Statement of claim of Elsworth Moore in the Carbon Ditch Enlargement,” available from the Colorado Department of Water Resources, DWR_WC_00146183.pdf.

[38] Gunnison Basin Implementation Plan page 20, 73-74, draft dated 7-3-2014.

[39] See Table A-1, Lysimeter‐Derived Grass Crop Coefficients (for use with the Original Blaney‐Criddle Method), page A-4, footnote 3.

[40] Alfalfa Irrigation and Drought, G. Shewmaker, R. Allen, and W. H. Neibling, Univ. of Idaho, 2011.

[41] Alfalfa Production Systems in California, UC Davis, 2007, pg. 3, http://alfalfa.ucdavis.edu/IrrigatedAlfalfa/pdfs/UCAlfalfa8287ProdSystems_free.pdf.

[42] Alfalfa Irrigation and Drought, footnote 19.

[43] Waskom, R.M., et al. Best Management Practices for Irrigated Agriculture: A Guide for Colorado Producers. Colorado Water Resources Research Institute, 1994, pg. 34..

[44] Etdata.org, downloaded July 5, 2024.