When California, Arizona and Nevada agreed last week to stop using 3 million acre-feet of Colorado River water — about a trillion gallons — in order to protect their drinking supply, they took aim at one especially thirsty user: hay. So-called “forage crops” like alfalfa and Bermuda grass, which are used to feed livestock, mainly cattle, require mind-altering amounts of water to cultivate. For the next three years, the states agreed to pay farmers who ordinarily grow livestock feed $1.2 billion not to. That alone is estimated to conserve the lion’s share of the trillion-gallon target.
Agriculture slurps 80% of the Colorado River in the U.S. each year, and a single forage crop, alfalfa hay, is responsible for over a third of that drain.
Alfalfa, meaning “fodder” in Arabic, is the nutrient-rich linchpin of the dairy and beef business. No other field crop produces more protein per acre. But that bounty comes with high water use. Alfalfa has a long growing season — another plus for farmers — a deep root system and a leafy, dense canopy that needs immense moisture to stay green. But that’s not the whole story: A century-old legal doctrine compels farmers to use as much river water as they’re allotted, or else lose access to the unused portion in the future. That perverse incentive, combined with the cheap Colorado River water afforded to many Western water districts, means that wasteful irrigation methods have not gone out of fashion. That includes a technique called “flood irrigation,” which is exactly what it sounds like: watering hundreds of alfalfa acres at a time by briefly flooding the field.
It’s a popular solution; the practice is simple to implement, recharges underground aquifers, and can create temporary havens for migrating birds. But it’s also wildly inefficient. So are those “central pivot” sprinklers that water perfect circles of crops — the ones that look like scattered green coins from an airplane window or a satellite. Those steel arms sweeping across the fields are less wasteful than flood irrigation, but far below the efficiency achieved by drip systems. Arizona and California alfalfa watered by the rolling sprinklers can soak up 800 to 1,200 gallons per minute, per sprinkler, during summer months. In contrast, a typical eight-minute shower at home uses about 17 gallons. All told, alfalfa swallows triple the water used by every household in all seven states the river supplies.
The driest regions in the West grow the thirstiest hay.
California’s Imperial Valley, a juggernaut of hay output, laps up more water than anywhere in the whole Colorado River Basin, accounting for 80%of the state’s allotment. Over a third of the 2.6 million acre-feet the All-American Canal brings into the valley goes to alfalfa fields. Located in the Sonoran Desert, it’s one of the hottest places in California and one of the driest, too — even drier than Las Vegas, averaging three inches of rain a year. All of that poses a problem for alfalfa, which gets stressed when soil moisture drops and temperatures climb. So, in order to keep the fields healthy in hot places like the Imperial Valley, southern Arizona and central Nevada, farms make up the difference in other ways, primarily by using irrigation to simulate New Hampshire-levels of rain in the desert. Heat-stressed alfalfa can require the equivalent of 46 inches of precipitation in a single growing season. Since regions like the Imperial Valley receive a fraction of that, farmers turn to water sources like the Colorado River to make up the rest.
But alfalfa reaps good money for arid farms.
Farmers working in unforgiving desert climates have their own reasons for cultivating alfalfa. For one, with enough irrigation, it can handle the ferocious summers in the West better than many fruit and vegetable varieties. It’s also a serious cash crop: Between 2012 and 2021 in California, alfalfa fetched more dollars per ton than any other hay variety for nine years straight. It dominates agriculture in Arizona, Nevada, New Mexico and Utah, the four driest states in the country, all of which depend on the Colorado River.
In fact, much of the Colorado River is exported as hay. Rising demand for dairy products in the Middle East and skyrocketing beef consumption across the globe are driving up the demand; 40% of the alfalfa grown in California in 2020 was shrink-wrapped, containerized, and shipped to cows on the other side of Earth.
When states and the federal government come to the table to finalize plans for the river cuts, they’ll have to balance those financial gains against the water requirements of the Southwest’s people, ecosystems and other crops. Meanwhile, the federal government still needs to review last week’s deal, and the states and the other parties involved will have to hammer out the finer points over the next several months.
Note: This story previously included an incorrect translation of alfalfa in Arabic. It was also updated to correct the acre-feet of water supplied through the All-American Canal and the irrigation requirements for alfalfa.
Samuel Shaw is an editorial intern for High Country News based in the Colorado Front Range. Email him at samuel.shaw@hcn.org or submit a letter to the editor. See our letters to the editor policy. Follow Samuel on Instagram @youngandforgettable.
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