Your Winter Vegetables: Brought to You
by California's Very Last Drops of Water
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By Tom Philpott |
MotherJones |
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California's drought-plagued Central
Valley hogs the headlines, but two-thirds of your winter
vegetables come from a different part of the state. Occupying a
land mass a mere eighth the size of metro Los Angeles, the
Imperial Valley churns out about two-thirds of the vegetables
eaten by Americans during the winter. Major crops include
broccoli, cabbage, carrots, cauliflower, and, most famously,
lettuce and salad mix.
Two-thirds
of winter broccoli, cabbage, carrots, cauliflower, lettuce, and
salad mix come from the desperately dry Imperial Valley.
And those aren't even the region's biggest
moneymakers. Nestled in the state's southeastern corner, the
Imperial Valley also produces massive amounts of alfalfa, a
cattle feed, and its teeming feedlots finish some 350,000 beef
cows per year.
In terms of native aquatic resources, the
Imperial makes the Central Valley look like Waterworld. At least
the Central Valley is bound by mountain ranges to the east that,
in good years (not the last several), deliver abundant snowmelt
for irrigation. The Imperial sits in the middle of the
blazing-hot Sonoran Dessert, with no water-trapping mountains
anywhere nearby. It receives a whopping 3 inches of
precipitation per year on average; even the more arid half of
the Central Valley gets 15 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 down from its source in the snow-capped peaks of northern
Colorado down to Mexico, it delivers a total of 16.5 million
acre-feet of water to the farmers and 40 million consumers in
seven US states and northern Mexico who rely on it. (An
acre-foot is the amount it takes to flood an acre of land with
12 inches of water—about 326,000 gallons.)
Of that total, the Imperial Valley's farms
gets 3.1 million acre-feet annually—more than half of
California's total allotment and more than any other state draws
from the river besides Colorado. It's an amount of water
equivalent to more than four times what Los Angeles uses in a
year, according to figures from the Pacific Institute. |
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The Colorado Rivers waters are so in demand that they
rarely reach their endpoint in Mexico's Sea of Cortez. Map:
Shannon/Wikimedia Commons |
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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. Currently, the
Rocky Mountain snowpack that feeds the Colorado stands at about
44 percent of its average for this time of year, triggering
fears of an impending shortfall—but not for the Imperial.
"Nevada, southern Arizona and Mexico will be cut back before the
Imperial district loses a drop," The Los Angeles Times recently
reported. Whereas Central Valley farmers, reliant on vanishing
snowmelt from the Sierras, have seen their irrigation allotments
curtailed the last two years, growers in the Imperial Valley
haven't lost any water (though the Imperial Valley District did
agree to sell as much as 0.2 million acre-feet of water by 2021,
of its 3.1 million acre-foot allotment, to fast-growing San
Diego in a 2003 deal).
The
Imperial gets its allotments during low-flow years even when
other regions see reductions.
Already, decades of intensive desert farming have had severe
ecological effects, epitomized by that beleaguered inland body
of water known as the Salton Sea, which sits uneasily at the
Imperial's northern edge. Before the big irrigation projects
that made the valley bloom, what's now the Salton periodically
captured flood waters from the then-mighty Colorado River. Now
it's fed solely from Imperial Valley farm runoff, and as Dana
Goodyear shows in a superb recent New Yorker piece, it's slowly
decaying into a toxic mess—one that could "emit as much as a
hundred tons of fine, caustic dust a day, leading to respiratory
illness in the healthy and representing an acute hazard for
people with compromised immune systems."
Meanwhile, the Colorado's flow has proven inadequate to supply
the broader region's needs. In a paper last year (my account of
it here), University of California-Irvine and NASA researchers
found that farmers, landowners, and municipalities are
supplementing their river allocations by 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, an enormous
fossil resource siphoned away in less than a decade. |
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A desert in bloom: the Imperial
Valley as seen from space, from a photo taken by NASA astronauts
in 2002. Photo: NASA |
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Consider also that the Southwest's population is on pace to expand by a
third by 2030—and that the river's annual average flow is
expected to decrease by anywhere from 5 percent to 18 percent by
2050, compared to 20th century averages, according to the
National Climate Assessment, throttled by rising temperatures
and declining precipitation.
Thus the Imperial's titanic water allotment is looking
increasingly vulnerable to challenge. Just as we probably need
to get used to sourcing more of our summer fruits and vegetables
from places beyond California's Central and Salinas valleys, the
Colorado River situation makes me wonder if we shouldn't rethink
those bountiful supermarket produce aisles in February, as well. |
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