What is the Future of Farming in a World of Water Shortages?
Tom Philpott on California Agriculture and the Anxieties of Scarcity
In the winter of 2018-19, California farmers hit the jackpot. An onslaught of more than thirty atmospheric rivers, none of them large enough to trigger significant floods, delivered a massive snowpack that measured more than 60 percent above average. “With full reservoirs and a dense snowpack, this year is practically a California water-supply dream,” Karla Nemeth, director of the state’s Department of Water Resources, declared at an April ceremony.
By September, farmers in the San Joaquin Valley were living a water-supply nightmare. CALIFORNIA FARMERS FACE “CATASTROPHIC” WATER RESTRICTIONS. CAN THEY ADAPT TO SURVIVE? declared a headline in the Sacramento Bee. Throughout the valley, especially in the Tulare region, water was in short supply. Farmers were experiencing their last season of unrestricted groundwater pumping, and staring into the abyss of California’s Sustainable Groundwater Management Act (SGMA), the 2014 law requiring that overpumped basins like the Tulare restrict pumping starting in 2020, so that aquifers come into balance by 2040.
The adjustment will mean draconian cuts in irrigation, and “that will mean a lot fewer pistachios, grapes, almonds and tomatoes,” the Bee reported. Water anxiety was sweeping the valley, the Bee continued:
Eric Limas, who runs a groundwater agency in the Pixley area of Tulare County, says his water allotment will be downright frightening: Farmers on his turf will have to curtail their groundwater usage by 40 percent eventually. “You’re talking devastation here, in the catastrophe spectrum,” Limas said.
In other words, even in increasingly rare “good” snowpack years—even in “dream” ones, like 2018-19—Farmers in the nation’s most productive agricultural valley rely on pumped groundwater to irrigate their crops. That means hard choices are ahead. “You’re farming almonds and I’m farming carrots. Your ability and willingness to pay for water is greater than mine. That’s the economics,” one Kern County water manager told the Bee. Translation: nut crops, with their massive embedded investments and booming overseas markets, will grab the most water, at the expense of vegetables.
The plight of water-starved San Joaquin Valley farmers barely penetrated the national conversation at the time. But California’s mounting water scarcity will be impossible to ignore when drought recurs, as it inevitably will. Meanwhile, as water stress continues to force a shift from annual crops like vegetables to perennial ones like almonds in the San Joaquin Valley, it might be tempting to hope that other regions in California will fill any shortfall in the supermarket produce aisle.
For the full picture of the state’s coming agricultural crisis, we need to consider two other California regions that are significant suppliers to the national food market: the Salinas Valley, known as the “Salad Bowl of the World”; and the Imperial Valley, which specializes in fresh winter produce. They, too, face severe and intensifying water jeopardy.
A rifle-shaped slice of land between two mountain ranges just south of Monterey Bay, off the state’s central coast, the Salinas Valley churns out more than half the salad greens and half the broccoli consumed in the United States. Its leafy-green dominance has earned it its nickname. But unlike the Central Valley, it suffered almost no consequences from the 2012-16 drought. That’s because farmers in the semi-arid Salinas, unlike their Central Valley counterparts, have no access to snowmelt diverted from a mountain range. Instead, they rely nearly 100 percent on underground aquifers, drought or no. And that means, in the short term, the state’s vicious periodic snowmelt droughts can actually be economically beneficial: they don’t affect production in the aquifer-irrigated Salinas, but they force water-scarce farms in the Central Valley to cut back on nonpermanent crops like lettuce, reducing supply and pushing up prices.
But all isn’t well under those sunbaked fields teeming with ripe vegetables. For one thing, decades of heavy nitrogen-fertilizer use have left underground water widely contaminated with high levels of nitrate, placing a heavy burden on farmworker communities that rely largely on wells and lack access to filtration infrastructure. The USGS shows that 20 percent of the region’s wells have nitrate levels over the legal limit. High housing prices, a spillover from the nearby Bay Area, apply another squeeze. The region’s ninety thousand farmworkers live at an average residential housing rate of seven people per one-room apartment. Nearly 60 percent of the region’s largely farmworker population live near or below the poverty line.
Worse, the region’s aquifers, the lifeblood of its $8.2 billion ag economy and sole source of the region’s drinking and irrigation water, are in a “state of long-term overdraft,” a 2014 assessment from California’s Water Foundation found. The paper notes that all eight of the Salinas Valley’s aquifers were listed as among the most-stressed aquifers by the California Department of Water Resources. As irrigation wells draw down the valley’s underground reservoirs, seawater from Monterey Bay seeps into the void, threatening to make the water too salty for farming. In response, in 2017, the Monterey County Water Resources Agency’s board of supervisors imposed a moratorium on digging new wells in one large swath of the region, which enraged agricultural interests and will limit their future water access if the prohibitions remains in place. While efforts are afoot to halt seawater intrusion and bring the aquifers into balance, the process—if it succeeds—will be expensive and likely result in farmland needing to be fallowed or abandoned. This, in turn, could mean pricier salad greens and strawberries for the produce aisle.
Then there’s the Imperial Valley, a bone-dry chunk of the Sonoran Desert bordering Arizona and Mexico in California’s southeast corner. The Imperial Valley (along with neighboring Yuma County in Arizona) churns out more than half the vegetables eaten by Americans during the winter. Major crops include broccoli, carrots, cauliflower, and, most famously, lettuce and salad mix. Overall, Imperial producers deliver about 14 percent of all leafy greens consumed domestically. In terms of native aquatic resources, the Imperial Valley makes the Central Valley look like Waterworld. At least the Central Valley is bounded by a mountain range to the east that, in good years, delivers abundant snowmelt for irrigation. The Imperial sits in the middle of a blazing-hot desert, with no water-trapping mountains anywhere nearby. It receives a whopping three inches of precipitation per year on average; even the more arid parts of the Central Valley get five inches.
The sole source of water in the Imperial Valley is the Colorado River, which originates hundreds of miles northeast, in the snowy peaks of the Rocky Mountains. As it winds from its source down to Mexico, the Colorado delivers—in theory—a total of 16.5 million acre-feet of water to the farmers and 40 million consumers in seven U.S. states and northern Mexico who rely on it. (An acre-foot is the amount it takes to flood an acre of land with twelve inches of water—about 326,000 gallons.) The river has been oversubscribed for nearly a century; the 16.5 million acre-feet estimate derives from average flows recorded in the early 20th century, before the river had become fully exploited by the western states. Since 1922, the average flow has been 14.8 million acre-feet. As of 2015, the ten-year average stood at 13.4 million acre-feet. That’s because the Rocky Mountain snowpack that feeds the Colorado River declined by 41 percent between 1982 and 2017. It is expected to dwindle by another 30 percent by mid-century.
As the river is depleted, the farms in California’s Imperial Valley retain a tight grip over 2.6 million acre-feet of water—more than half the state’s total allotment and more than any other state draws from the river besides Colorado. Because it owns senior water rights based on a 1931 pact, the Imperial gets its allotments during low-flow years even when other regions see reductions. Whereas Central Valley farmers, reliant on vanishing snowmelt from the Sierras, saw their irrigation allotments slashed to zero during the Great Drought of 2011-17, growers in the Imperial Valley didn’t miss a beat.
Pressure to share some of this water with the Southwest’s burgeoning metropolises has been growing for decades. Under heavy political tension, the Imperial Irrigation District agreed to sell 200,000 acre-feet annually of water to fast-expanding San Diego in a 2003 deal that lasts until 2047. Calls to send Colorado River water to cities will mount as the climate warms and the Rocky Mountain snowpack recedes.
These tussles over control of the Colorado’s flow become devastatingly visible at the shores of a beleaguered inland body of water that sits uneasily at the Imperial’s northern edge: the Salton Sea, the original sin of the region’s booming farming sector. Before the big irrigation projects that made the valley bloom, it was known as the Salton Sink—a depression sitting 235 feet beneath sea level. For millennia, it periodically captured floodwater from the then mighty Colorado, in the odd year when the river careened off its normal path to drain into the Gulf of California. These intermittent flows fed the area’s ground with river silt, creating a fertile soil base.
In the early 20th century, U.S. settlers began diverting a portion of the Colorado River west to the Salton Sink. In 1905, their designs worked all too well. A heavy snowpack in the Rockies combined with an engineering blunder to divert the river’s entire flow into the Salton depression, an unintended deluge that lasted eighteen months. The modern Salton Sea was born: it instantly became and remains the state’s largest lake. For years, it flourished. The valley’s farmers claimed their massive share of the river’s annual flow, now diverted in orderly fashion (after the rise of publicly funded, professionally managed aqueducts); drainage from farm irrigation would flow into the lake, more or less balancing evaporation and allowing the lake to hold its size. The Salton Sea emerged as a swank resort; pop stars from Frank Sinatra to the Pointer Sisters to the Beach Boys entertained there. The water teemed with fish, and it became a stopping point for migrating birds along the Pacific Flyway now that the vast, ancient network of rivers, lakes, and wetlands to the north in the modern Central Valley had been dammed and drained for farming.
Over time, moderate levels of salt from irrigation runoff built up in the lake, intensified by evaporation under the desert sun (which carries away water but leaves minerals behind). By the 1980s, the lake’s salinity became too high to support most fish species, leading to massive die-offs. The resort withered as the lake began to emit the odor of rotting organic matter.
More recently, the San Diego water transfer forced the valley’s farmers to use water more efficiently. The resulting widespread switch to drip irrigation meant less farm runoff, and thus less water flow into the Salton, which began to shrink in size (and grow even saltier) as evaporation outpaced inflow. As the Salton contracts, the desert sun quickly dries the exposed lake bottom, and the wind picks up the fine-particulate dust. Consequently, children in Imperial County endure asthma hospitalizations at twice the
State’s average rate. And as millions of fish corpses decay in the water, the lake periodically releases vast plumes of hydrogen sulfide, which can foul the air with a rotten-egg stench as far away as Los Angeles. If present trends hold, the Salton will continue shrinking, subjecting the Imperial Valley’s residents—mostly farmworkers—to ever-more toxic air. State policymakers have been puzzling for decades over the best way to mitigate this slow-build ecological disaster; so far, the only clear consensus is that doing it right will require a “staggering” amount of Colorado River water.
The added burden of replenishing the Salton Sea looks especially onerous in light of the fact that the Colorado’s flow has already proved inadequate to supply the broader region’s needs. In a 2014 paper, U.C. Irvine and NASA researchers found that farmers and municipalities are quietly supplementing their river allocations by tapping wells and drawing water from underground aquifers at a much faster rate than had been known. Between December 2004 and November 2013, the Colorado Basin lost almost 53 million acre-feet of underground water, the equivalent of more than four annual flows of the Colorado River. That’s an enormous fossil resource siphoned away in less than a decade.
“Quite honestly, we are alarmed and concerned about the implications of our findings,” study coauthor Jay Famiglietti wrote at the time. “From a group that studies groundwater depletion in the hottest of the hot spots of water stress around the world—in India, the Middle East, and in California’s Central Valley—that says something.” In short, Famiglietti writes, “The American West is running out of water.”
Excerpted from Perilous Bounty by Tom Philpott. Copyright © 2020. Reprinted with permission of the publisher, Bloomsbury Publishing.