The Dammed - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 157

issues, navigation, fish and wildlife protection, recreation, and water research projects.
But the Bureau is best known for the dams it built across most major Western rivers.
The golden age of the Water Buffaloes began in 1928, when Congress authorized
the bureau to build Hoover Dam , which impounds over 9 trillion gallons of Colorado
River water in Lake Mead. Hoover Dam—originally called Boulder Dam, after Boulder
Canyon, the steep gorge in which it was built, and controversially renamed for President
Herbert Hoover, who personally ensured its funding and construction—is a magnifi-
cent structure designed with refined art deco touches. It is an “arch-gravity” dam (a dam
that curves upstream, which directs water pressure against the canyon walls), with a
thin top and a thick bottom, which allows brittle concrete to withstand immense water
pressure. Its construction was an epic undertaking, requiring 66 million tons of con-
crete (the most ever for a project at the time) and the invention of innovative engin-
eering techniques, such as special coils that cooled the concrete as it was poured into
trapezoidal forms so that it would cure without cracking. The dam caused the deaths of
112 men during construction and led to the rise of Las Vegas as a center of gambling
and drinking in a traditionally Mormon region. The largest dam in the world when it
was built, Hoover produces about 4 billion kilowatt-hours of hydroelectric power a year,
enough to service 1.3 million people in Arizona, Nevada, and California.
Like most large dams, Hoover Dam was controversial from the moment it was con-
ceived. Arizona saw it as a water grab by California; East Coast legislators saw it as a
drain on the treasury; the power industry saw its hydroelectric turbines as unwanted
competition; and wealthy landowners saw it as a threat to the irrigation they depended
on.
Hoover Dam and its reservoir, Lake Mead, block the Colorado River's natural flood-
ing, which scours the riverbed and helps plant and animal species reseed. The dam
proved devastating to native plants and fish along the river—such as the razorback suck-
er, the humpback chub, the bony-tail chub, and the Colorado pikeminnow, all of which
are now listed as endangered species. It took six years to fill Lake Mead in the late
thirties, and during that time virtually no water reached the mouth of the Colorado
River, where it should empty into the Sea of Cortés. The delta's estuary once boasted a
mixing zone (where freshwater mixes with salt water, producing a rich ecosystem) that
stretched forty miles south of the Colorado's outflow. But dams along the river, espe-
cially Hoover, choked the freshwater flow so fiercely that the estuary's salinity was raised
to unprecedented heights, which wreaked havoc on estuarine flora and fauna; the last
time the Colorado reached the Sea of Cortés was in 2003.
The Bureau of Reclamation was unmoved by the environmentalists' protests. With
the triumphant completion of Hoover Dam, substantial funds began to flow from
Washington, DC, to Bureau projects across the arid West for the next half a century.