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The Crop That’s Sucking the Colorado River Dry



This article was originally published by High Country News.

Last month, California, Arizona, and Nevada agreed to conserve 3 million acre-feet of Colorado River water—about a trillion gallons—through 2026 in order to protect their drinking supply. The agreement will likely cause big changes for one especially thirsty user: hay. So-called forage crops such as alfalfa and Bermuda grass, which are used to feed livestock, require large amounts of water to cultivate. For the next three years, the states agreed to pay cities, irrigation districts, and Native American tribes $1.2 billion to use less water, including paying many farmers not to farm.

Agriculture accounts for almost 80 percent of the water consumed in the Colorado River Basin each year, and alfalfa is responsible for more than a third of that drain.

Alfalfa, a nutrient-rich option for feeding dairy and beef cattle, produces a huge amount of 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 plenty of moisture to stay green. That’s not the whole story: Water-rights laws incentivize ranchers to use as much river water as they’re allotted, or else risk losing access to the unused portion in the future. And because the Colorado River has afforded cheap water to many western districts, 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, might help recharge 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 from an airplane window or a satellite like scattered green coins. Those steel arms sweeping across the fields are less wasteful than flood irrigation but below the efficiency achieved by drip systems. Arizona and California alfalfa watered by these sprinklers can soak up several hundred gallons a minute for a 130-acre field. In contrast, a typical eight-minute shower at home uses about 16 gallons. All told, alfalfa swallows triple the water used by everyone in the region to shower, water lawns, and do laundry.


California’s Imperial Valley, a juggernaut of hay output, laps up more water than anywhere in the whole Colorado River Basin, accounting for nearly 80 percent of the state’s allotment. Much of the roughly 2.5 million acre-feet of water that 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. All of that poses a problem for alfalfa, which gets stressed when soil moisture drops and temperatures climb. In order to keep the fields healthy in hot places such as the Imperial Valley, southern Arizona, and central Nevada, farms make up the difference in other ways, primarily by using irrigation. Alfalfa can require the equivalent of dozens of inches of precipitation in a single growing season. Because regions like the Imperial Valley receive a fraction of that, farmers turn to water sources such as the Colorado River to make up the rest.

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. Alfalfa is also profitable: From 2012 to 2021 in California, it fetched more dollars a ton than any other hay variety. Alfalfa is important to agriculture in Arizona, Nevada, New Mexico, and Utah, among the 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 and beef across the globe are driving up the demand; by one estimate, 40 percent of the alfalfa grown in California in 2020 was exported.

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 month’s deal, and the states and the other parties involved will have to hammer out the finer points over the next several months.

Source: The Atlantic


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