WSP09765

• File Number: 8220.200.05.A
• Description: Hoover Dam/Lake Mead/Boulder Canyon Project
• Basin: Colorado Mainstem
• Date: 1/1/1987
• Author: USDOI/BOR
• Title: Hoover Dam: Arizona/Nevada
• Water Supply Pro - Doc Type: Publication

J-:. In 1985 Hoover Dom was designated by the Department of
~ the Interior os a National Historic landmark, and by the
.-. American Society of Civil Engineers as a Notional Historic
Civil Engineering Landmark.

c: Hoover Dam was without precedent, the greatest dam
constructed in its day. An arch.gravity structure rising 726
feet above bedrock, Hoover is still the Western
Hemisphere's highest concrete dam. It is 660 feet thick at
its base, 45 feet thick at its crest, and stretches 1,244 feet
across the Block Canyon. There are 4.4 million cubic yards
of concrete in the dam, powerplant, and related
structures.

The reservoir, lake Mead. is America's largest man-made
reservoir. Named for Dr. Elwood Mead, Reclamation
Commissioner from 1924 fa 1936, the lake backs up 110
miles behind the dam and is capable of storing 28.5
million acre-feet of water. (An acre.foot of water is
325,851 gallons, or enough to cover on acre to 0 depth of
one foot.)

Multipurpose Benefits

Hoover Dam pioneered the Bureau of Reclamation's efforts
in multiple-purpose water resources development. The
dam controls floods; stores water for irrigation, municipal,
and industrial uses; and provides hydroelectric power
generation, recreation, and fish and wildlife habitat.

Hoover Dam's reservoir, Lake Mead, can store nearly 2
years at overage Colorado River flow. This water is
released in a regulated, year-round flow as needed.

Water stored in Lake Mead irrigates three-quarters of a
million acres of land in this country and nearly one-half
million acres in Mexico. The water helps meet the
municipal and industrial needs of over 14 million people.

As it passes through Hoover's turbines, the water
generates low-cost hydroelectric power for use in Nevada,
Arizona, and California. About 4 billion kilowatt-hours of
energy, enough for 500,000 homes, are generated
annually.

Water that was once muddy is now sparkling clear in
reservoirs and in stretches of the river. Hoover and other
dams on the Colorado hove tamed the turbulent flow,
creating clean bodies of water that provide recreation for
more than 10 million people each year. These waters
hove also formed habitats tor fish and wildlife in lands
that were once nearly barren.

Hoover Dam changed the Colorado River from a natural
menace to a national resource, strengthening the
economy of the Southwest and the Nation.

Farms

Colorado River water stored behind Hoover Dam irrigates
some of America's richest farmlands. Valley and mesa
lands in the warm desert climate along the river grow a
wide variety of fruits. vegetables, and other nonsurplus
crops throughout the year for the Notion's dinner tables.

Yearly gross income from these crops averages hundreds
of dollars per acre. In 1985, for example, the total gross
crop value in the (oachella and Imperial Valleys was
nearly $839 million, or over $1,700 per irrigated acre.

Major irrigation projects which benefit from Hoover's
control and regulation of the Colorado River include the
Polo Verde Valley, the Colorado River Indian Reservation,
the Yuma and Gila Projects in Arizona, and the Imperial
and Coachella Valleys in California.

The AlI.American Canal System diverts water from the
Colorado River at Imperial Dam. When the water reaches
the farthest point on the system, it has traveled 10 days
and some 500 miles from Lake Mead.

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