The City That Wasn’t Supposed to Be - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 137

CHAPTER 15
The City That Wasn't Supposed to Be
There is no lack of water here [in the Southwest], unless you try to establish a
city where no city should be.
—Edward Abbey
THE SIMPLE MATH OF DROUGHT
Lake Mead, the largest man-made reservoir in the United States, is surrounded by steep
cliffs that come in many shades of ruddy brown, except for a strange white band that runs
along their base, just above the water-line, encircling the lake like a noose. Known as the
bathtub ring, the white band is the result of the cliffs being submerged in calcium-rich
water, which bleached out the color. But starting in 1999, the Southwest was gripped by
the worst drought in five hundred years; over the next decade the reservoir's water level
dropped more than one hundred feet, and the bathtub ring grew steadily wider and more
ominous.
Lake Mead was formed in 1935 , when Hoover Dam impounded the Colorado River
in Boulder Canyon, containing up to 9.3 trillion gallons of water when full. Ninety-
seven percent of the lake's water comes from the Colorado River; the remaining 3 percent
comes from the Muddy and Virgin Rivers, and from a wetland called the Las Vegas Wash.
Mead was built to supply water to Nevada, Arizona, and California; to generate electri-
city; to prevent flooding during wet years; and to create a recreational area. Mead's chief
beneficiary is Las Vegas. The lake provides 90 percent of the city's water, and experts
worry that Las Vegas's near total reliance on a single troubled source makes it vulnerable
to a crippling drought.
When I took a boat ride around Lake Mead in the spring of 2008, the drought was in
its eighth year, and the white bathtub ring extended a startling 102 feet up the cliff face.
he water level had dropped from 1,215 feet in 2000 to 1,095 feet in 2008, its lowest el-
evation since 1964. If the lake sinks below 1,050 feet, the water level will be beneath the
intake valves—a state known as dead pool —and Las Vegas will lose up to 90 percent of
its water supply. If that happens, people would have to abandon the city, the glittering
Strip would go dark, and the desert would reassert itself.