The Colorado River Is Shrinking. See What’s Using All the Water.
The water supply that 40 million Americans rely on has been pushed to its limit. Reservoirs and wells are running low. This week, the states that rely on water from the Colorado River reached a temporary deal with the Biden administration on sharing what’s left.
What’s using all that water?
The majority of the water in the Colorado River basin — more than one trillion gallons — is used to grow feed for livestock, connecting the region’s water crisis to how much dairy and meat we eat.
The crops grown for humans to eat directly, like vegetables, use up less than a quarter of the amount of water that livestock feed does, according to estimates from a 2020 study published in Nature Sustainability. And residential consumption, like watering your lawn and taking showers, uses a fifth of what livestock feed does.
A limited resource
The Colorado River system stretches across seven states in the Southwest and Mexico, and a complicated set of decades-old laws determines who gets water from the river, and how much. Those rules promised more water than the system could sustainably give, experts have said, an imbalance that’s worsening as climate change dries out even more of the West.
That has led to the widespread use of thirsty crops under “a presumption that water is cheap and abundant,” said Heather Cooley, director of research at the Pacific Institute, a research group focused on global water challenges. “But that’s not the reality.”
The chart above captures both river water and groundwater withdrawals, but river water makes up the vast majority (about 87 percent) of water use in the basin, according to the study’s authors.
The water footprint of food
To put it in perspective, it could take more than 38 gallons of water, by some estimates, to produce one quarter-pound beef patty. That includes the water to grow all the feed like alfalfa and hay that the cattle themselves eat. In comparison, you need about five gallons of water to get the same amount of protein from tofu.
Dairy products like milk and cheese are even more water-intensive per gram of protein than beef because dairy cows require more energy to produce milk. They’re often fed alfalfa, in part because it’s higher in calories and protein. Some tree nuts like almonds can use a relatively large amount of water as well.
Water footprint estimates can vary widely depending on the conditions that the livestock are raised in, or the farming practices and technology used. But, in general, beef and dairy are some of the most water-intensive foods we consume. Raising cattle also contributes relatively more greenhouse gas emissions, particularly methane, than most other food.
And, on average, Americans eat a lot of beef and dairy.
About that alfalfa
Thirty-seven percent of the water used in the Colorado River basin goes toward growing alfalfa and hay used largely to feed dairy cattle. That’s triple the water that residents in the region use to water lawns, take showers and wash clothes. Alfalfa is a thirsty crop, in part because of its lengthy growing season that allows for multiple harvests per year.
It’s an export, too. Researchers estimated in the 2020 study that 10 to 12 percent of the irrigated cattle-feed crops grown in the United States are exported, and about 10 percent of beef is exported.
The big picture
Although agriculture dominates water consumption in the West, most of the new demand for water comes from growing cities, Ms. Cooley said, and there are a lot of opportunities to conserve water at the tap.
Fewer lawns could make a difference. But experts say what we eat remains the biggest driver of water use along the Colorado.
“We have to be thinking about dietary changes,” said Brian Richter, lead author of the 2020 study and president of the education organization Sustainable Waters.
That doesn’t necessarily mean quitting meat entirely. Instead, it might look like a mind-set shift: Those products might need to become more of a specialty item in our diets, he said, “rather than something we consume every day.”