How Much Water Could California Save?

California’s in the middle of its most significant drought in half a millennia. According to Jay Famiglietti, senior water cycle scientist at NASA’s Jet Propulsion Laboratory, the Golden State’s reservoirs contain only a one-year supply* of water. If California continues to be caught in this drought through 2016, America (and much of the world) might be a whole lot hungrier. By many calculations, 80 percent of California’s developed water supply is dedicated to agricultural needs. The state’s vast and historically fertile lands, particularly in the Central Valley, have made it the nation’s number one producer of countless desirable crops: walnuts, strawberries, avocados, broccoli, carrots, cauliflower, grapes, lettuce, peppers, spinach, tomatoes, artichokes…

Though the list goes on, these days, there’s one California crop in particular that’s causing a stir. In recent years, almonds have surged in popularity, far surpassing peanuts to become America’s favorite nut. (Well, fruit seed, technically.) 99 percent of the U.S. almond supply—and 80 percent of the world’s—is grown in the heart of the Central Valley, which has been devasted by the current drought. Almonds are the state’s most lucrative agricultural export by far, doubling 2009 gross revenues in 2013 to bring in $6.2 billion, and now take up a huge percentage of the Central Valley’s farmland—44 percent more land than in 2012.

But growing even one almond in an arid climate using modern methods takes a great deal of water. One gallon, to be precise. All told, after doubling in production over the last decade, almonds today suck up somewhere between three and 10 percent of California’s water supply. A gallon sounds like a lot. But is it? Compared to a grape, which needs less than 0.3 of a gallon—definitely. Compared to a tomato, which takes three gallons? Not so much. And almonds aren’t even the thirstiest tree nut—every single California-grown walnut soaks up nearly five gallons of the state’s dwindling H₂O reserves. All bets are off if you throw meat or dairy into the mix. A gallon of milk requires a staggering 880 gallons of water for bottling, processing, raising, and grazing cattle. (75 percent of California’s alfalfa hay is fed to dairy cows, by the way, and the crop sucks up more water than almonds—15 percent of California’s supply).

With thirsty crops growing in a drought-stricken California that affects the state's water supply, research has proven that changing how California distributes its water to agriculture can make a big difference. Chart by Addison Eaton and Helga Salinas

So why’s everyone so worked up about the almond, if it’s just one of many thirsty crops? For starters: It’s the way almonds are grown. In the middle of a dry spell, farmers can decide not to plant row crops like cotton or grapes, then replant them later when more water’s available. But nut trees require a decade of steady water before they’re able to yield enough product to pay for themselves. To repeat that: Almond trees must be watered even when they’re not producing. Today, after years spent chasing the multi-million dollar promise of America’s favorite fruit seed, many California farms are deciding to sacrifice the trees they’ve spent their life savings to cultivate—before the drought decides for them.

If an arid area like the Central Valley is going to continue as America’s—and in many ways, the world’s—agricultural center, the state needs to be smarter about what kinds of water it uses for which purposes. By reusing water, capturing stormwater, and employing water-saving practices in both urban and rural areas, enough water could be saved to supply all cities in California.

Progress has already been made on the agricultural front. In 1990, more than two-thirds of California crops were flood-irrigated. Twenty years later, that number was down to 43 percent, as the use of more efficient microsprinklers and drip irrigation—which conserves water by decreasing runoff and applying water directly to the root zone—increased from 15 to 38 percent.

Promising, but what about the other 62 percent? As seen in the chart above, there are other methods for water conservation besides moving to more efficient methods like drip irrigation, including irrigation scheduling which uses local climate and soil information to specify the amount of water used for each crops; and regulated deficit irrigation that applies less water to specific crops that have drought-tolerant growth stages.

Some are calling for a return to wilder varieties of almond—a historically drought-tolerant crop that has thrived in locales much drier than the Central Valley—and “dry farming.” This very old method trains roots to grow deeper, helping almonds tap into natural sources of water on their own. From TakePart:

No one is going to replant the Valley’s more than 900,000 acres of sweet almonds with [...] a wild Iranian almond overnight. Creating a drought-tolerant future for almond growing in California requires separating what’s above and below the soil. Growers could continue to harvest [sweet almonds] while the trees are grown on the rootstock of wild or drought-tolerant domesticated varieties. That’s because almond trees, like other fruit trees and vine crops [...] can be grafted onto the roots of another variety or even that of a close cousin, such as peach, apricot, or plum.

Dry farming likely isn’t scalable for commercial agricultural enterprises. But it just might be very well-suited for today’s smaller organic farms. And it’s high time for California to regulate its groundwater more strategically. At the moment, overlying land owners are mostly unmonitored by the state’s water boards when it comes to groundwater use. But drilling into the ground for water is both expensive and inexact; as of late, some neighbors are draining their neighbors dry; others have been known to inadvertently tap into aquifers with dangerous levels of arsenic. As the California Almond Board puts it, the crop has added “more than 100,000 jobs and $11 billion to the state’s economy.” Farmers will find any way they can to grow almonds because people really, really want to eat them: They’re the number one U.S. specialty crop. But almonds are far from the only thirsty crop growing in California. And more droughts are sure to strike—in the American west and elsewhere— as temperatures around the world continue to rise. (Some even suggest that the current drought is so devastating not because of lack of rainfall, but because the excessive heat has accelerated evaporation.) We need to work for change now if the world wants to continue to eat the way it does today.

Though California’s water crisis is complex, Groundswell offers easy advice for those of who shop for food, rather than produce it: Be more mindful about how much water it took to produce what you love to eat. Calculate how many gallons of water your favorite foodstuff tends to drink up, then try to offset that amount as best you can by flushing less, dishwashing only full loads, and shortening your showers.

In fact, do that anyway. Household water use may be a drop in the bucket when compared to agriculture, and your shorter shower won’t stop this drought, or the next one. But it’s a good start.

*This story has been updated to include Mr. Famiglietti’s most recent estimates. Previously, the story stated that California had two years of water in its reservoirs. Illustration by Addison Eaton