Hoover Dam

Hoover Dam
Hoover Dam by Ansel Adams, 1941
Official name	Hoover Dam
Location	Clark County, Nevada/Mohave County, Arizona, U.S.
Purpose	Power, flood control, water storage, regulation, recreation
Status	Operational
Construction began	1931
Opening date	1936 (88 years ago) (1936)
Construction cost	$49 million (1931 budget) ($790 million in 2023 dollars[1])
Owner(s)	United States government
Operator(s)	U.S. Bureau of Reclamation
Dam and spillways
Type of dam	Concrete gravity-arch dam
Impounds	Colorado River
Height	726.4 ft (221.4 m)
Length	1,244 ft (379 m)
Elevation at crest	1,232 ft (376 m)
Width (crest)	45 ft (14 m)
Width (base)	660 ft (200 m)
Dam volume	3,250,000 cu yd (2,480,000 m3)
Spillway type	2 controlled Drum-Gate, Side channel
Spillway capacity	400,000 cu ft/s (11,000 m3/s)
Reservoir
Creates	Lake Mead
Total capacity	28,537,000 acre⋅ft (35.200 km3)
Active capacity	15,853,000 acre⋅ft (19.554 km3)
Inactive capacity	10,024,000 acre⋅ft (12.364 km3)
Catchment area	167,800 sq mi (435,000 km2)
Surface area	247 sq mi (640 km2)[2]
Maximum length	112 mi (180 km)
Maximum water depth	590 ft (180 m)
Normal elevation	1,219 ft (372 m)
Power Station
Operator(s)	U.S. Bureau of Reclamation
Commission date	1936–1960
Hydraulic head	590 ft (180 m) (Max)
Turbines	13 × 130 MW 2 × 127 MW 1 × 68.5 MW 1 × 61.5 MW Francis-type 2 × 2.4 MW Pelton-type
Installed capacity	2,078.8 MW
Capacity factor	23%
Annual generation	3.3 TWh (12 PJ) (2020)[3]
Website Bureau of Reclamation: Lower Colorado Region - Hoover Dam
Hoover Dam
U.S. National Register of Historic Places
U.S. National Historic Landmark
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Nearest city	Boulder City, Nevada
Coordinates	36°0′56″N 114°44′16″W / 36.01556°N 114.73778°W / 36.01556; -114.73778
Built	1933
Architect	Six Companies, Inc. (structural), Gordon Kaufmann (exteriors)
Architectural style	Art Deco
MPS	Vehicular Bridges in Arizona MPS (AD)
NRHP reference No.	81000382
Significant dates
First Power Generation	September 11, 1936[6]
Added to NRHP	April 8, 1981[4]
Designated NHL	August 20, 1985[5]

Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. Constructed between 1931 and 1936, during the Great Depression, it was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over 100 lives. In bills passed by Congress during its construction, it was referred to as the Hoover Dam, after President Herbert Hoover, but was named Boulder Dam by the Roosevelt administration. In 1947, the name Hoover Dam was restored by Congress.

Since about 1900, the Black Canyon and nearby Boulder Canyon had been investigated for their potential to support a dam that would control floods, provide irrigation water, and produce hydroelectric power. In 1928, Congress authorized the project. The winning bid to build the dam was submitted by a consortium named Six Companies, Inc., which began construction in early 1931. Such a large concrete structure had never been built before, and some of the techniques used were unproven. The torrid summer weather and lack of facilities near the site also presented difficulties. Nevertheless, Six Companies turned the dam over to the federal government on March 1, 1936, more than two years ahead of schedule.

Hoover Dam impounds Lake Mead and is located near Boulder City, Nevada, a municipality originally constructed for workers on the construction project, about 30 mi (48 km) southeast of Las Vegas, Nevada. The dam's generators provide power for public and private utilities in Nevada, Arizona, and California. Hoover Dam is a major tourist attraction, with 7 million tourists a year.^[7] The heavily traveled U.S. Route 93 (US 93) ran along the dam's crest until October 2010, when the Hoover Dam Bypass opened.