hoover dam construction

[30], The city of Las Vegas had lobbied hard to be the headquarters for the dam construction, closing its many speakeasies when the decision maker, Secretary of the Interior Ray Wilbur, came to town. Known as McKeeversville, the camp was home to … [115], Hoover Dam opened for tours in 1937 after its completion, but following Japan's attack on Pearl Harbor on December 7, 1941, it was closed to the public when the United States entered World War II, during which only authorized traffic, in convoys, was permitted. [33] Another camp, on the flats along the Colorado River, was officially called Williamsville, but was known to its inhabitants as "Ragtown". When workers wearing such headgear were struck hard enough to inflict broken jaws, they sustained no skull damage. After a catastrophic breach that caused the Colorado River to fill the Salton Sea,[8] the Southern Pacific Railroad spent $3 million in 1906–07 to stabilize the waterway, an amount it hoped in vain would be reimbursed by the federal government. The Fall-Davis report cited use of the Colorado River as a federal concern because the river's basin covered several states, and the river eventually entered Mexico. However, at the time, the limit of transmission of electric power was 80 miles (130 km), and there were few customers (mostly mines) within that limit. [31], Soon after the dam was authorized, increasing numbers of unemployed people converged on southern Nevada. The government was to provide the materials; but the contractor was to prepare the site and build the dam. He was noncommittal. [51] The inner diversion tunnels were plugged at approximately one-third of their length, beyond which they now carry steel pipes connecting the intake towers to the power plant and outlet works. [36] "Mongolian" (Chinese) labor was prevented by the construction contract,[36] while the number of blacks employed by Six Companies never exceeded thirty, mostly lowest-pay-scale laborers in a segregated crew, who were issued separate water buckets. [6] The dam 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. [68] Despite the change in the ceremony time, and temperatures of 102 °F (39 °C), 10,000 people were present for the President's speech, in which he avoided mentioning the name of former President Hoover,[69] who was not invited to the ceremony. These buckets, which weighed 20 short tons (18 t) when full, were filled at two massive concrete plants on the Nevada side, and were delivered to the site in special railcars. Power is generated in step with and only with the release of water in response to downstream water demands. [90] Hansen's bas-relief on the Nevada elevator tower depicts the benefits of the dam: flood control, navigation, irrigation, water storage, and power. Fortune Magazine - September 1933 (continued) ARTHUR POWELL DAVIS is the chief unsung hero of Boulder Dam. The construction site had, even then, become a magnet for tourists; the high scalers were prime attractions and showed off for the watchers. Since the dam was an arch-gravity type, the side-walls of the canyon would bear the force of the impounded lake. Instead, the ground where the dam would rise was marked with rectangles, and concrete blocks in columns were poured, some as large as 50 ft square (15 m) and 5 feet (1.5 m) high. The entire flow of the Colorado River passes through the turbines. [119] For six years after the construction of the dam, while Lake Mead filled, virtually no water reached the mouth of the river. [118], The changes in water flow and use caused by Hoover Dam's construction and operation have had a large impact on the Colorado River Delta. The Bureau of Reclamation, more concerned with the dam's functionality, adorned it with a Gothic-inspired balustrade and eagle statues. After the war, it reopened September 2, 1945, and by 1953, annual attendance had risen to 448,081. The workers were given until 5 p.m. to vacate the premises. As that dam was a curved-gravity type,[20] similar in design to the arch-gravity as was proposed for the Black Canyon dam, opponents claimed that the Black Canyon dam's safety could not be guaranteed. Las Vegas, then a small city of some 5,000, saw between 10,000 and 20,000 unemployed descend on it. [131], In the following years, the name "Boulder Dam" failed to fully take hold, with many Americans using both names interchangeably and mapmakers divided as to which name should be printed. The spillways and outlet works (jet-flow gates) are rarely used. [110] The 1941 damage was attributed to a slight misalignment of the tunnel invert (or base), which caused cavitation, a phenomenon in fast-flowing liquids in which vapor bubbles collapse with explosive force. The dam is not listed among the world’s largest dams, but it is certainly among the tallest, with its heavy concrete walls being 222 meters high. In total, water from Lake Mead serves 18 million people in Arizona, Nevada and California and supplies the irrigation of over 1,000,000 acres (400,000 ha) of land. [18] Initial talks produced no result, but when the Supreme Court handed down the Wyoming v. Colorado decision undermining the claims of the upstream states, they became anxious to reach an agreement. The heavily traveled U.S. Route 93 (US 93) ran along the dam's crest until October 2010, when the Hoover Dam Bypass opened. By September 1939, four more generators were operating, and the dam's power plant became the largest hydroelectricity facility in the world. The Nevada Southern Railway is the last remaining stretch of the historic train tracks used to build the Hoover Dam. [74] The first was surveyor John Gregory ("J.G.") [27], The Wattis Brothers, heads of the Utah Construction Company, were interested in bidding on the project, but lacked the money for the performance bond. [10], In the following years, the Bureau of Reclamation (BOR), known as the Reclamation Service at the time, also considered the Lower Colorado as the site for a dam. [78], Ninety-six of the deaths occurred during construction at the site. [50], To protect the construction site from the Colorado River and to facilitate the river's diversion, two cofferdams were constructed. The monolithic dam would be thick at the bottom and thin near the top, and would present a convex face towards the water above the dam. Nevertheless, Six Companies turned the dam over to the federal government on March 1, 1936, more than two years ahead of schedule. [34] When construction began, Six Companies hired large numbers of workers, with more than 3,000 on the payroll by 1932[35] and with employment peaking at 5,251 in July 1934. 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. Living conditions began to improve as the first residents moved into Boulder City in late 1931. [119] The construction of the dam has been implicated in causing the decline of this estuarine ecosystem. Hoover Dam. Hoover Dam, formerly called Boulder Dam, dam in Black Canyon on the Colorado River, at the Arizona - Nevada border, U.S. [16], With little guidance on water allocation from the Supreme Court, proponents of the dam feared endless litigation. [3] The jet-flow gates, located in concrete structures 180 feet (55 m) above the river and also at the outlets of the inner diversion tunnels at river level, may be used to divert water around the dam in emergency or flood conditions, but have never done so, and in practice are used only to drain water from the penstocks for maintenance. On Dec. 26, 1947, New York City woke up to a record-breaking snowstorm that dumped over 22 inches of snow in less than 24 hours. Service chief Arthur Powell Davis proposed using dynamite to collapse the walls of Boulder Canyon,[11] 20 miles (32 km) north of the eventual dam site, into the river. Hoover Dam is a colossal hydroelectric dam on the Colorado River, on the border between Nevada and Arizona. On July 7, 1930, construction of the Hoover Dam, originally called the Boulder Dam, began in Black Canyon on the Colorado River on the border of Nevada and Arizona. Holes were driven into the walls and base of the canyon, as deep as 150 feet (46 m) into the rock, and any cavities encountered were to be filled with grout. [26], On January 10, 1931, the Bureau made the bid documents available to interested parties, at five dollars a copy. Frank Crow, was the Chief Engineer of Hoovered Dam and was assigned the job to get it completed in the span from 1931 - 1935. During this excavation, approximately 1,500,000 cu yd (1,100,000 m3) of material was removed. This town became known as Boulder City, Nevada. Both times, when inspecting the tunnels after the spillways were used, engineers found major damage to the concrete linings and underlying rock. Nowadays this amount is about 788 million pounds. Workers alleged that this diagnosis was a cover for death from carbon monoxide poisoning (brought on by the use of gasoline-fueled vehicles in the diversion tunnels), and a classification used by Six Companies to avoid paying compensation claims. [101][102], In 2018, the Los Angeles Department of Water and Power (LADWP) proposed a $3 billion pumped hydro storage project—a "battery" of sorts—that would use wind and solar power to recirculate water back up to Lake Mead from a pumping station 20 miles (32 km) downriver. The original timetable called for Boulder City to be built before the dam project began, but President Hoover ordered work on the dam to begin in March 1931 rather than in October. A total of 58 of the 393 holes were incompletely filled. [28] The joint venture was called Six Companies, Inc. as Bechtel and Kaiser were considered one company for purposes of Six in the name. [61] It took nine years (1938–47) under relative secrecy to complete the supplemental grout curtain. Workers with families were left to provide their own accommodations until Boulder City could be completed,[39] and many lived in Ragtown. When the bottom of the bucket opened up, disgorging 8 cu yd (6.1 m3) of concrete, a team of men worked it throughout the form. The final generator was not placed in service until 1961, bringing the maximum generating capacity to 1,345 megawatts at the time. [24] It also permitted the compact to go into effect when at least six of the seven states approved it. [15] Despite the site change, the dam project was referred to as the "Boulder Canyon Project". A decade in pictures: Iconic stories, photos and covers of the 1990s, In memoriam: Remembering the famous figures we lost in 2020, Winter fun: Stars enjoy the colder weather, A decade in pictures: Iconic stories, photos and covers of the 1980s, 25 New Year’s resolutions that are actually achievable, A decade in pictures: Iconic stories, photos and covers of the 1950s, Sneak peek at the 'Coming 2 America' movie. [9], As the technology of electric power transmission improved, the Lower Colorado was considered for its hydroelectric-power potential. This was done by exploding a temporary cofferdam protecting the Arizona tunnels while at the same time dumping rubble into the river until its natural course was blocked. [29] There were three valid bids, and Six Companies' bid of $48,890,955 was the lowest, within $24,000 of the confidential government estimate of what the dam would cost to build, and five million dollars less than the next-lowest bid. Movable sections of steel forms were used for the sidewalls. It was dedicated on September 30, 1935, by President Franklin D. Roosevelt. The sidewalls were poured next. [50] Their combined length was nearly 16,000 ft, or more than 3 miles (5 km). In 1928, Congress authorized the project. Each gate weighs 5,000,000 pounds (2,300 metric tons) and can be operated manually or automatically. [81] Kaufmann greatly streamlined the design and applied an elegant Art Deco style to the entire project. [62], The first concrete was poured into the dam on June 6, 1933, 18 months ahead of schedule. 3.9 out of 5 stars 44. [22] The Boulder Canyon Project Act[23] appropriated $165 million for the Hoover Dam along with the downstream Imperial Dam and All-American Canal, a replacement for Beatty's canal entirely on the U.S. side of the border. The map depicts the Northern Hemisphere sky at the moment of President Roosevelt's dedication of the dam. The name was descriptive and was an inside joke among the San Franciscans in the bid, where "Six Companies" was also a Chinese benevolent association in the city. Revisit what was called The Great Blizzard of 1947 in New York Daily News photographs. [124][125], During the years of lobbying leading up to the passage of legislation authorizing the dam in 1928, the press generally referred to the dam as "Boulder Dam" or as "Boulder Canyon Dam", even though the proposed site had shifted to Black Canyon. Because of the dam's remote location and difficult terrain, a town had to be built to house the construction companies and their workers. [56], The men who removed this rock were called "high scalers". [126], When Secretary of the Interior Ray Wilbur spoke at the ceremony starting the building of the railway between Las Vegas and the dam site on September 17, 1930, he named the dam "Hoover Dam", citing a tradition of naming dams after Presidents, though none had been so honored during their terms of office. The parties came to an agreement and on March 1, 1936, Secretary Ickes formally accepted the dam on behalf of the government. [17] Such compacts were authorized by Article I of the United States Constitution but had never been concluded among more than two states. After the dam was authorized, thousands of workers came to southern Nevada to work on the dam. In 1995, a new visitors' center was built, and the following year, visits exceeded one million for the first time. Known as McKeeversville, the camp was home to men hoping for work on the project, together with their families. [12] The river would carry off the smaller pieces of debris, and a dam would be built incorporating the remaining rubble. The upper cofferdam was 96 ft (29 m) high, and 750 feet (230 m) thick at its base, thicker than the dam itself. Tierney, fell from one of the two Arizona-side intake towers. On March 12, 1928, the failure of the St. Francis Dam, constructed by the city of Los Angeles, caused a disastrous flood that killed up to 600 people. [3] In 2015, the dam generated 3.6 TWh. Railcars carried the fresh concrete for the dam in 4 by 8 cubic-yard buckets with overhead cableways lowering the concrete to the dam forms. "[133] Ickes, who was by then a private citizen, opposed the change, stating, "I didn't know Hoover was that small a man to take credit for something he had nothing to do with. With the opening of the bypass, through traffic is no longer allowed across Hoover Dam; dam visitors are allowed to use the existing roadway to approach from the Nevada side and cross to parking lots and other facilities on the Arizona side. Concerned that a violent confrontation was imminent, most workers took their paychecks and left for Las Vegas to await developments. [98] Due to the low water levels, by 2014 it was providing power only during periods of peak demand. Instead, Wilbur announced in early 1930 that a model city was to be built in the desert near the dam site. Over the next five years, a total of 21,000 men would work ceaselessly to produce what would be the largest dam of its time, as well as one of the largest manmade structures in the world. The dam closed again to the public on September 11, 2001; modified tours were resumed in December and a new "Discovery Tour" was added the following year. [14] One potential site at Boulder Canyon was bisected by a geologic fault; two others were so narrow there was no space for a construction camp at the bottom of the canyon[14] or for a spillway. [3] The annual generation of Hoover Dam varies. [122] The construction of the dam devastated the populations of native fish in the river downstream from the dam. [85] The images and colors are based on Native American visions of rain, lightning, water, clouds, and local animals—lizards, serpents, birds—and on the Southwestern landscape of stepped mesas. Although the dam would take only five years to build, its construction was nearly 30 years in the making. Edison allowed land options it held on the river to lapse—including an option for what became the site of Hoover Dam. Hoover Dam was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. [59], The cleared, underlying rock foundation of the dam site was reinforced with grout, forming a grout curtain. [95] Following an uprating project from 1986 to 1993, the total gross power rating for the plant, including two 2.4 megawatt Pelton turbine-generators that power Hoover Dam's own operations is a maximum capacity of 2080 megawatts. At the height of construction, a bucket arrived every 78 seconds. Pending the completion of the bypass, restricted traffic was permitted over Hoover Dam. On August 13, the company began hiring workers again, and two days later, the strike was called off. [50] The inner tunnels' outlets are equipped with gates that can be closed to drain the tunnels for maintenance. The Hoover Dam: The History and Construction of America’s Most Famous Engineering Project. [101], Lake Mead and downstream releases from the dam also provide water for both municipal and irrigation uses. "[132], Hoover Dam was recognized as a National Civil Engineering Landmark in 1984. The spillway entrance arrangement forms a classic side-flow weir with each spillway containing four 100-foot-long (30 m) and 16-foot-wide (4.9 m) steel-drum gates. Even today, 75 years after it was built, it remains one of the largest, most reliable hydroelectric […] [16] The Boulder Canyon Project Act of 1928 (BCPA) never mentioned a proposed name or title for the dam. Hoover Dam 75th Anniversary - Photographs, a video, and media coverage of the September 30, 2010 event at the dam. [44] On August 7, 1931, the company cut wages for all tunnel workers. [72], There were 112 deaths reported as associated with the construction of the dam. [92] To make the powerhouse roof bombproof, it was constructed of layers of concrete, rock, and steel with a total thickness of about 3.5 feet (1.1 m), topped with layers of sand and tar. [83] In these works, which are integrated into the walkways and interior halls of the dam, True also reflected on the machinery of the operation, making the symbolic patterns appear both ancient and modern. Its base is as thick as two football fields … For the dam to rest on solid rock, it was necessary to remove accumulated erosion soils and other loose materials in the riverbed until sound bedrock was reached. [100], Control of water was the primary concern in the building of the dam. The dam's generators provide power for public and private utilities in Nevada, Arizona, and California. The report was principally authored by Davis, and was called the Fall-Davis report after Interior Secretary Albert Fall. On this day in 1930, construction of the Hoover Dam begins. These tunnels were 56 ft (17 m) in diameter. Past efforts at forcing the Colorado under human will had met with varying degrees of success. To meet the deadline, Six Companies had to complete work by early 1933, since only in late fall and winter was the water level in the river low enough to safely divert. The dam is an arch gravity structure rising 726 feet above bedrock. [41] Sixteen workers and other riverbank residents died of heat prostration between June 25 and July 26, 1931. [80] A total of 42 workers were recorded as having died from pneumonia and were not included in the above total; none were listed as having died from carbon monoxide poisoning. A $2 million bid bond was to accompany each bid; the winner would have to post a $5 million performance bond. [82], At Kaufmann's request, Denver artist Allen Tupper True[81] was hired to handle the design and decoration of the walls and floors of the new dam. The only self-guided tour option is for the visitor center itself, where visitors can view various exhibits and enjoy a 360-degree view of the dam. They formed a joint venture to bid for the project with Pacific Bridge Company of Portland, Oregon; Henry J. Kaiser & W. A. Bechtel Company of San Francisco; MacDonald & Kahn Ltd. of Los Angeles; and the J.F.

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