Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

Dam dimensions:Height: 726.4 ft; length at crest: 1244 ft; width at top: 45 ft; width at

base: 660 ft

Weight:6.6 million tons

Reservoir statistics:Capacity: 28,537,000 acre-feet; length: 110 mi; shoreline: 550 mi; max

depth: 500 ft; surface area:157,000 acres

Quantities of materials used in project:Concrete: 4,440,000 yd

3

; explosives: 6,500,000 lb;

plate steel and outlet pipes: 88,000,000 lb; pipe and fittings: 6,700,000 lb (840 mi); re-

inforcement steel: 45,000,000 lb; concrete mix proportions: cement: 1.00 part, sand:

2.45 parts, fine gravel: 1.75 parts, intermediate gravel: 1.46 parts, coarse gravel: 1.66 parts,

cobbles (3 to 9 in.): 2.18 parts; water: 0.54 parts

The dam was built in blocks, or vertical columns, varying in size from approximately 60 ft

square at the upstream face of the dam to about 25 ft square at the downstream face. Adjacent

columns were locked together by a system of vertical keys on the radial joints and horizontal

keys on the circumferential joints. After the concrete was cooled, a cement and water mixture

called grout was forced into the spaces created between the columns by the contraction of the

cooled concrete to form a monolithic (one-piece) structure.

Hoover Dam itself contains 3.25 million yd

3

of concrete. Altogether, there are

4,360,000 yd

3

of concrete in the dam, power plant, and appurtenant works. This much

concrete would build a monument 100 ft square and 2-1/2 mi high; would rise higher than

the Empire State Building (which is 1250 ft) if placed on an ordinary city block; or would pave

a standard highway, 16 ft wide, from San Francisco to New York City.

The Reservoir At elevation 1221.4, Lake Mead, the largest man-made lake in the United States,

contains 28,537,000 acre-feet (an acre-foot is the amount of water required to cover 1 acre to

a depth of 1 foot). This reservoir will store the entire average flow of the river for two years. That

much water would cover the entire state of Pennsylvania to a depth of 1 ft.

Lake Mead extends approximately 110 mi upstream toward the Grand Canyon and

approximately 35 mi up the Virgin River. The width of Lake Mead varies from several hun-

dred feet in the canyons to a maximum of 8 mi. The reservoir covers about 157,900 acres, or

247 square miles.

Recreation, although a by-product of this project, constitutes a major use of the lakes and

controlled flows created by Hoover and other dams on the lower Colorado River today. Lake

Mead is one of America’s most popular recreation areas, with a 12-month season that attracts

more than 9 million visitors each year for swimming, boating, skiing, and fishing. The lake

and surrounding area are administered by the National Park Service as part of the Lake Mead

National Recreation Area, which also includes Lake Mohave downstream from Hoover Dam.

The Power Plant There are 17 main turbines in the Hoover Power plant. The original tur-

bines were all replaced through an upgrading program between 1986 and 1993. With a rated

capacity of 2,991,000 hp, and two station-service units rated at 3500 hp each, for a plant total

of 2,998,000 hp, the plant has a nameplate capacity of 2,074,000 kW. This includes the two

station-service units, which are rated at 2400 kW each.

Hoover Dam generates low-cost hydroelectric power for use in Nevada, Arizona, and

California. Hoover Dam alone generates more than 4 billion kWh a year — enough to serve

1.3 million people. From 1939 to 1949, the Hoover Power plant was the world’s largest

414 Chapter 13 Energy and Power

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