Morrison–Knudsen (MK) was an American civil engineering and construction company, with headquarters in Boise, Idaho .
106-596: MK designed and constructed major infrastructure throughout the world and was one of the consortium of firms that built Hoover Dam , San Francisco–Oakland Bay Bridge , the Trans-Alaska Pipeline , and many other large projects of American infrastructure . MK's origins date to 1905, when Harry Morrison, Chairman and President met Morris Knudsen while working on the construction of the New York Canal ( Boise Project ) in southwestern Idaho. Morrison
212-429: 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
318-491: A flash flood while looking for an ideal spot for the dam was the second person. The official list's final death occurred on December 20, 1935, when Patrick Tierney, electrician's helper and the son of J.G. Tierney, fell from one of the two Arizona-side intake towers. Included in the fatality list are three workers who took their own lives on site, one in 1932 and two in 1933. Of the 112 fatalities, 91 were Six Companies employees, three were Bureau of Reclamation employees, and one
424-449: A form by only 1 inch (25 mm), and Six Companies engineers would not have permitted a flaw caused by the presence of a human body. A total of 3,250,000 cubic yards (2,480,000 cubic meters) of concrete was used in the dam before concrete pouring ceased on May 29, 1935. In addition, 1,110,000 cu yd (850,000 m ) were used in the power plant and other works. More than 582 miles (937 km) of cooling pipes were placed within
530-778: A greatly diminished presence in Idaho, the last positions in Boise were eliminated in 2015. Hoover Dam This is an accepted version of this page 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
636-483: A model city was to be built in the desert near the dam site. This town became known as Boulder City, Nevada . Construction of a rail line joining Las Vegas and the dam site began in September 1930. Soon after the dam was authorized, increasing numbers of unemployed people converged on southern Nevada. Las Vegas, then a small city of some 5,000, saw between 10,000 and 20,000 unemployed descend on it. A government camp
742-588: A new record low elevation of 1,071.61 feet (326.63 m) on July 1, 2016, before beginning to rebound slowly. Under its original design, the dam would no longer be able to generate power once the water level fell below 1,050 feet (320 m), which might have occurred in 2017 had water restrictions not been enforced. To lower the minimum power pool elevation from 1,050 to 950 feet (320 to 290 m), five wide-head turbines, designed to work efficiently with less flow, were installed. Water levels were maintained at over 1,075 feet (328 m) in 2018 and 2019, but fell to
848-443: A new record low of 1,071.55 feet (326.61 m) on June 10, 2021 and were projected to fall below 1,066 feet (325 m) by the end of 2021. Control of water was the primary concern in the building of the dam. Power generation has allowed the dam project to be self-sustaining: proceeds from the sale of power repaid the 50-year construction loan, and those revenues also finance the multimillion-dollar yearly maintenance budget. Power
954-413: A pumping station 20 miles (32 km) downriver. Electricity from the dam's powerhouse was originally sold pursuant to a fifty-year contract, authorized by Congress in 1934, which ran from 1937 to 1987. In 1984, Congress passed a new statute which set power allocations to southern California, Arizona, and Nevada from the dam from 1987 to 2017. The powerhouse was run under the original authorization by
1060-406: A scathing interview to a newspaper, describing the workers as "malcontents". On the morning of the 9th, Crowe met with the committee and told them that management refused their demands, was stopping all work, and was laying off the entire work force, except for a few office workers and carpenters. The workers were given until 5 p.m. to vacate the premises. Concerned that a violent confrontation
1166-416: A separate rail systems division in 1972. Initially, the company rebuilt locomotives, such as the four Delaware & Hudson ALCO PAs . It rebuilt four Southern Pacific GE U25Bs with a Sulzer V-12 prime mover . These locomotives, designated M-K TE70-4S , operated from 1978 to 1987. It also built locomotives, originally under its own name and later under subsidiary MK Rail from 1994 to 1996, such as
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#17327833979691272-493: A set of 1-inch (25 mm) steel pipes; cool river water would be poured through the pipes, followed by ice-cold water from a refrigeration plant. When an individual block had cured and had stopped contracting, the pipes were filled with grout . Grout was also used to fill the hairline spaces between columns, which were grooved to increase the strength of the joints. The concrete was delivered in huge steel buckets 7 feet high (2.1 m) and almost 7 feet in diameter; Crowe
1378-405: A slope towards almost certain death, a high scaler was able to intercept him and pull him into the air. The construction site had become a magnet for tourists. The high scalers were prime attractions and showed off for the watchers. The high scalers received considerable media attention, with one worker dubbed the "Human Pendulum" for swinging co-workers (and, at other times, cases of dynamite) across
1484-697: Is a major tourist attraction, with 7 million tourists a year. The heavily traveled U.S. Route 93 (US 93) ran along the dam's crest until October 2010, when the Hoover Dam Bypass opened. As the United States developed the Southwest, the Colorado River was seen as a potential source of irrigation water. An initial attempt at diverting the river for irrigation purposes occurred in the late 1890s, when land speculator William Beatty built
1590-526: Is generated in step with and only with the release of water in response to downstream water demands. Lake Mead and downstream releases from the dam also provide water for both municipal and irrigation uses. Water released from the Hoover Dam eventually reaches several canals. The Colorado River Aqueduct and Central Arizona Project branch off Lake Havasu while the All-American Canal
1696-448: Is not subject to alkali–silica reaction (ASR), as the Hoover Dam builders happened to use nonreactive aggregate, unlike that at downstream Parker Dam , where ASR has caused measurable deterioration. With most work finished on the dam itself (the powerhouse remained uncompleted), a formal dedication ceremony was arranged for September 30, 1935, to coincide with a western tour being made by President Franklin D. Roosevelt . The morning of
1802-658: Is now a wholly owned subsidiary of Wabtec. MK also entered the passenger railcar rebuilding market in the 1980s, initially located at the former Erie Railroad shop in Hornell, New York . It overhauled and rebuilt many New York City Transit subway cars between 1984 and 1992 including all R26 / R28s , all R29s , most R32s , some R36s (through a pilot program), many R42s , many R44s , and all R46s . It also overhauled NJ Transit 's Arrow I series cars, converting from electric MUs to Comet 1B push-pull coaches, and SEPTA 's Silverliner II and III series electric commuter cars in
1908-630: Is supplied by the Imperial Dam . 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. In 2018, the Los Angeles Department of Water and Power (LADWP) proposed a $ 3 billion pumped-storage hydroelectricity project—a "battery" of sorts—that would use wind and solar power to recirculate water back up to Lake Mead from
2014-815: The Alamo Canal just north of the Mexican border; the canal dipped into Mexico before running to a desolate area Beatty named the Imperial Valley . Though water from the Alamo Canal allowed for the widespread settlement of the valley, the canal proved expensive to operate. After a catastrophic breach that caused the Colorado River to fill the Salton Sea , the Southern Pacific Railroad spent $ 3 million in 1906–07 to stabilize
2120-723: The BART C2 cars was opened in Pittsburg, California in 1993. MK also built Metra gallery cars , Amtrak Viewliner I sleeping cars , the Caltrans California Cars (1994–96) and other rail passenger cars and light rail. By 1995, Morrison–Knudsen was facing bankruptcy, with more than 60% of the company's previous-year net loss of $ 350 million occurring in the MK Transit division. A special purpose company, named Amerail (American Passenger Rail Car Company),
2226-477: The J.F. Shea Company of Portland, Oregon. The joint venture was called Six Companies, Inc. as Bechtel and Kaiser were considered one company for purposes of Six in the name. 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 . There were three valid bids, and Six Companies' bid of $ 48,890,955
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#17327833979692332-581: The Kabul government tasked Morrison-Knudsen with a large array of construction tasks in Afghanistan , including irrigation and a hydroelectric dam in the Helmand Province area. Morrison was featured on the cover of Time magazine on May 3, 1954, and the article claimed Morrison was "the man who has done more than anyone else to change the face of the earth." In the late 1950s, MK constructed
2438-665: The MK5000C and the F40PHM-2C . Its Australian operation, based in Whyalla , South Australia , rebuilt 17 CL and eight AL class locomotives for Australian National and six DE class locomotives for BHP in the 1990s. Morrison–Knudsen spun-off MK Rail in 1993; it became a publicly traded company in 1994. After Morrison–Knudsen's bankruptcy in 1996 the company renamed itself MotivePower . The company merged with Westinghouse Air Brake Company in 1999 to form Wabtec . MotivePower
2544-614: The Nationally Determined Contributions for the Paris Agreement , Suriname has committed to emissions controls for vehicles and increased public transit investment. NOTE: Driving is on the left . Suriname and its neighbour Guyana are the only two countries on the (in-land) American continent which still drive on the left. 1,200 km; most important means of transport; oceangoing vessels with drafts ranging up to 7 m can navigate many of
2650-537: The Parker , Shasta and Grand Coulee dams and power plants. True's work on the Hoover Dam was humorously referred to in a poem published in The New Yorker , part of which read, "lose the spark, and justify the dream; but also worthy of remark will be the color scheme". Complementing Kaufmann and True's work, sculptor Oskar J. W. Hansen designed many of the sculptures on and around the dam. His works include
2756-581: The Utah Construction Company , were interested in bidding on the project, but lacked the money for the performance bond. They lacked sufficient resources even in combination with their longtime partners, Morrison-Knudsen , which employed the nation's leading dam builder, Frank Crowe . 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
2862-656: The BART C2 cars. After this transfer, the site was used for overhaul of the older BART A and B cars . Morrison–Knudsen had also bid on this contract, but lost out to AEG Transportation Systems (who were then acquired by Daimler-Benz , becoming part of Adtranz shortly after). The Hornell site was bought by GEC-Alsthom in July 1997, following unsuccessful attempts at a joint venture to bid on new contracts. The final site in Chicago closed in mid-1998, when work on contracts for Metra
2968-545: The Boulder Canyon Project, the Bureau of Reclamation was considering what kind of dam should be used. Officials eventually decided on a massive concrete arch-gravity dam , the design of which was overseen by the Bureau's chief design engineer John L. Savage . 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. The curving arch of
3074-433: The Colorado River usually passes through the turbines. The spillways and outlet works (jet-flow gates) are rarely used. 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
3180-595: The Federal government to supplement the pay, but no money was forthcoming from Washington. The strike ended. Before the dam could be built, the Colorado River needed to be diverted away from the construction site. To accomplish this, four diversion tunnels were driven through the canyon walls, two on the Nevada side and two on the Arizona side. These tunnels were 56 ft (17 m) in diameter. Their combined length
3286-501: The Los Angeles Department of Water and Power and Southern California Edison; in 1987, the Bureau of Reclamation assumed control. In 2011, Congress enacted legislation extending the current contracts until 2067, after setting aside 5% of Hoover Dam's power for sale to Native American tribes, electric cooperatives, and other entities. The new arrangement began on October 1, 2017. The Bureau of Reclamation reports that
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3392-502: The Nevada tunnels in May 1931. Shortly afterward, work began on two similar tunnels in the Arizona canyon wall. In March 1932, work began on lining the tunnels with concrete. First the base, or invert, was poured. Gantry cranes , running on rails through the entire length of each tunnel were used to place the concrete. The sidewalls were poured next. Movable sections of steel forms were used for
3498-588: The President's speech, in which he avoided mentioning the name of former President Hoover, who was not invited to the ceremony. To mark the occasion, a three-cent stamp was issued by the United States Post Office Department —bearing the name "Boulder Dam", the official name of the dam between 1933 and 1947. After the ceremony, Roosevelt made the first visit by any American president to Las Vegas. Most work had been completed by
3604-591: The Republic , were both formed in a continuous pour. To put such large bronzes into place without marring the highly polished bronze surface, they were placed on ice and guided into position as the ice melted. Hansen's bas-relief on the Nevada elevator tower depicts the benefits of the dam: flood control, navigation, irrigation, water storage, and power. The bas-relief on the Arizona elevator depicts, in his words, "the visages of those Indian tribes who have inhabited mountains and plains from ages distant." Excavation for
3710-620: The United States Constitution but had never been concluded among more than two states. In 1922, representatives of seven states met with then- Secretary of Commerce Herbert Hoover . 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 resulting Colorado River Compact
3816-562: The assistance of the National Laboratory of Anthropology, True researched authentic decorative motifs from Indian sand paintings, textiles, baskets and ceramics. 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. In these works, which are integrated into the walkways and interior halls of
3922-480: The bill authorizing the dam. The Boulder Canyon Project Act appropriated $ 165 million for the project 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. It also permitted the compact to go into effect when at least six of the seven states approved it. This occurred on March 6, 1929, with Utah's ratification; Arizona did not approve it until 1944. Even before Congress approved
4028-461: The bypass tunnels, as the tunnel had to be used to take in irrigation water until the powerhouse went into operation. There were 112 deaths reported as associated with the construction of the dam. The first was Bureau of Reclamation employee Harold Connelly who died on May 15, 1921, after falling from a barge while surveying the Colorado River for an ideal spot for the dam. Surveyor John Gregory ("J.G.") Tierney, who drowned on December 20, 1922, in
4134-429: The canyon. To protect themselves against falling objects, some high scalers dipped cloth hats in tar and allowed them to harden. When workers wearing such headgear were struck hard enough to inflict broken jaws, they sustained no skull damage. Six Companies ordered thousands of what initially were called "hard boiled hats" (later " hard hats ") and strongly encouraged their use. The cleared, underlying rock foundation of
4240-490: The clocks display the same time for more than half the year. At Kaufmann's request, Denver artist Allen Tupper True was hired to handle the design and decoration of the walls and floors of the new dam. True's design scheme incorporated motifs of the Navajo and Pueblo tribes of the region. Although some were initially opposed to these designs, True was given the go-ahead and was officially appointed consulting artist. With
4346-435: The company cut wages for all tunnel workers. Although the workers sent the organizers away, not wanting to be associated with the "Wobblies", they formed a committee to represent them with the company. The committee drew up a list of demands that evening and presented them to Crowe the following morning. He was noncommittal. The workers hoped that Crowe, the general superintendent of the job, would be sympathetic; instead, he gave
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4452-419: The concrete. Overall, there is enough concrete in the dam to pave a two-lane highway from San Francisco to New York. Concrete cores were removed from the dam for testing in 1995; they showed that "Hoover Dam's concrete has continued to slowly gain strength" and the dam is composed of a "durable concrete having a compressive strength exceeding the range typically found in normal mass concrete". Hoover Dam concrete
4558-481: The construction period. The initial plans for the facade of the dam, the power plant, the outlet tunnels and ornaments clashed with the modern look of an arch dam. The Bureau of Reclamation, more concerned with the dam's functionality, adorned it with a Gothic -inspired balustrade and eagle statues. This initial design was criticized by many as being too plain and unremarkable for a project of such immense scale, so Los Angeles-based architect Gordon B. Kaufmann , then
4664-459: The construction site was drained of water, excavation for the dam foundation began. 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. Work on the foundation excavations was completed in June 1933. During this excavation, approximately 1,500,000 cu yd (1,100,000 m ) of material
4770-408: The dam (from pea-sized gravel to 9 inches [230 mm] stones), it was vital that the bucket be maneuvered to the proper column. When the bottom of the bucket opened up, disgorging 8 cu yd (6.1 m ) of concrete, a team of men worked it throughout the form. Although there are myths that men were caught in the pour and are entombed in the dam to this day, each bucket deepened the concrete in
4876-529: The dam project was referred to as the "Boulder Canyon Project". With little guidance on water allocation from the Supreme Court , proponents of the dam feared endless litigation. Delph Carpenter, a Colorado attorney, proposed that the seven states which fell within the river's basin (California, Nevada, Arizona, Utah, New Mexico, Colorado and Wyoming) form an interstate compact , with the approval of Congress. Such compacts were authorized by Article I of
4982-536: The dam project. 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. As that dam was a curved-gravity type, 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. Congress authorized a board of engineers to review plans for
5088-399: The dam site was reinforced with grout , forming a grout curtain . 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. This was done to stabilize the rock, to prevent water from seeping past the dam through the canyon rock, and to limit "uplift"—upward pressure from water seeping under
5194-415: The dam would transmit the water's force into the abutments, in this case the rock walls of the canyon. The wedge-shaped dam would be 660 ft (200 m) thick at the bottom, narrowing to 45 ft (14 m) at the top, leaving room for a highway connecting Nevada and Arizona. On January 10, 1931, the Bureau made the bid documents available to interested parties, at five dollars a copy. The government
5300-444: The dam's total power output was placed on the grid and made arbitrarily distributable. Before water from Lake Mead reaches the turbines, it enters the intake towers and then four gradually narrowing penstocks which funnel the water down towards the powerhouse. The intakes provide a maximum hydraulic head (water pressure) of 590 ft (180 m) as the water reaches a speed of about 85 mph (140 km/h). The entire flow of
5406-405: The dam, True also reflected on the machinery of the operation, making the symbolic patterns appear both ancient and modern. With the agreement of Kaufmann and the engineers, True also devised for the pipes and machinery an innovative color-coding which was implemented throughout all BOR projects. True's consulting artist job lasted through 1942; it was extended so he could complete design work for
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#17327833979695512-409: The dam. The workers were under severe time constraints due to the beginning of the concrete pour. When they encountered hot springs or cavities too large to readily fill, they moved on without resolving the problem. A total of 58 of the 393 holes were incompletely filled. After the dam was completed and the lake began to fill, large numbers of significant leaks caused the Bureau of Reclamation to examine
5618-568: The daring." Hansen's dedication plaza, on the Nevada abutment, contains a sculpture of two winged figures flanking a flagpole. Surrounding the base of the monument is a terrazzo floor embedded with a "star map". The map depicts the Northern Hemisphere sky at the moment of President Roosevelt's dedication of the dam. This is intended to help future astronomers, if necessary, calculate the exact date of dedication. The 30-foot-high (9.1 m) bronze figures, dubbed Winged Figures of
5724-475: The dedication, and Six Companies negotiated with the government through late 1935 and early 1936 to settle all claims and arrange for the formal transfer of the dam to the Federal Government. The parties came to an agreement and on March 1, 1936, Secretary Ickes formally accepted the dam on behalf of the government. Six Companies was not required to complete work on one item, a concrete plug for one of
5830-520: The dedication, it was moved forward three hours from 2 p.m. Pacific time to 11 a.m.; this was done because Secretary of the Interior Harold L. Ickes had reserved a radio slot for the President for 2 p.m. but officials did not realize until the day of the ceremony that the slot was for 2 p.m. Eastern Time. Despite the change in the ceremony time, and temperatures of 102 °F (39 °C), 10,000 people were present for
5936-541: The diversion tunnels), and a classification used by Six Companies to avoid paying compensation claims. The site's diversion tunnels frequently reached 140 °F (60 °C), enveloped in thick plumes of vehicle exhaust gases. 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. No deaths of non-workers from pneumonia were recorded in Boulder City during
6042-590: The energy generated under the contracts ending in 2017 was allocated as follows: The dam is protected against over-topping by two spillways . The spillway entrances are located behind each dam abutment , running roughly parallel to the canyon walls. 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. Each gate weighs 5,000,000 pounds (2,300 metric tons) and can be operated manually or automatically. Gates are raised and lowered depending on water levels in
6148-620: The firm built irrigation canals, logging roads, and railways; they incorporated in 1923, the year gross revenues topped $ 1 million. MK reached a significant milestone with its joint venture in the construction of Hoover Dam (1932–35). During World War II, MK built airfields, storage depots, and bases throughout the Pacific , and built ships along the West Coast . Japanese forces captured 1,200 workers, including many MK employees, stationed on Midway and Wake Islands in late 1941. After
6254-418: The first residents moved into Boulder City in late 1931. A second labor action took place in July 1935, as construction on the dam wound down. When a Six Companies manager altered working times to force workers to take lunch on their own time, workers responded with a strike. Emboldened by Crowe's reversal of the lunch decree, workers raised their demands to include a $ 1-per-day raise. The company agreed to ask
6360-415: The first three Allis Chalmers built Francis turbine - generators , all on the Nevada side, began operating. In March 1937, one more Nevada generator went online and the first Arizona generator by August. By September 1939, four more generators were operating, and the dam's power plant became the largest hydroelectricity facility in the world. The final generator was not placed in service until 1961, bringing
6466-464: The following year) found that canyon unsuitable. 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 or for a spillway. The Service investigated Black Canyon and found it ideal; a railway could be laid from the railhead in Las Vegas to the top of the dam site. Despite the site change,
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#17327833979696572-614: 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. Service chief Arthur Powell Davis proposed using dynamite to collapse the walls of Boulder Canyon, 20 miles (32 km) north of the eventual dam site, into the river. The river would carry off the smaller pieces of debris, and a dam would be built incorporating
6678-571: The infamous "tiger cage" cells of Côn Sơn Prison . The group was called RMK-BRJ and included Raymond International, Brown & Root , and JA Jones Construction Company. MK was also involved in the construction of rail projects such as the Bay Area Rapid Transit (BART) extension (MK also built 80 C2 cars for BART in 1994) and the single track Apoera-Bakhuys Railway in Suriname (1976–1977). Morrison–Knudsen established
6784-450: The intake towers to the power plant and outlet works. The inner tunnels' outlets are equipped with gates that can be closed to drain the tunnels for maintenance. To protect the construction site from the Colorado River and to facilitate the river's diversion, two cofferdams were constructed. Work on the upper cofferdam began in September 1932, even though the river had not yet been diverted. The cofferdams were designed to protect against
6890-601: The largest companies in the industry. Following the acquisition, the MK's corporate name changed to Washington Group International in July 2000. Issues with the Raytheon acquisition caused WGI to declare bankruptcy in 2001 – virtually eliminating all shareholder value, but later successfully exited it. WGI was acquired by rival URS Corporation of San Francisco in 2007, which was acquired by AECOM of Los Angeles in 2014. With
6996-554: The late 1980s. Vehicles overhauled in the 1990s included Metra Highliner I EMU cars, an Amtrak Turboliner RTL-II , as well as BTC-1C passenger cars and US Standard Light Rail Vehicles for the MBTA . MK later expanded into building new cars, taking over the former Pullman Company factory in Chicago in 1992. The CTA 3200 series and Metro-North M6 "Cosmopolitan" cars were built by MK in 1992–1994. A third site for assembling
7102-576: The longest rail tunnel in the southern hemisphere. In the late 1960s and early 1970s, MK was involved in the construction of the Hamersley & Robe River and Mount Newman railways in the Pilbara region of Western Australia . From 1962 to 1972, MK managed a joint venture to serve the U.S. military as civilian contractors for infrastructure in the Vietnam War ; in 1971, they constructed 384 of
7208-409: The maximum generating capacity to 1,345 megawatts at the time. Original plans called for 16 large generators, eight on each side of the river, but two smaller generators were installed instead of one large one on the Arizona side for a total of 17. The smaller generators were used to serve smaller communities at a time when the output of each generator was dedicated to a single municipality, before
7314-400: The monument of dedication plaza, a plaque to memorialize the workers killed and the bas-reliefs on the elevator towers. In his words, Hansen wanted his work to express "the immutable calm of intellectual resolution, and the enormous power of trained physical strength, equally enthroned in placid triumph of scientific accomplishment", because "[t]he building of Hoover Dam belongs to the sagas of
7420-405: The payroll by 1932 and with employment peaking at 5,251 in July 1934. "Mongolian" (Chinese) labor was prevented by the construction contract, while the number of black people employed by Six Companies never exceeded thirty, mostly lowest-pay-scale laborers in a segregated crew, who were issued separate water buckets. As part of the contract, Six Companies, Inc. was to build Boulder City to house
7526-440: The penstocks for maintenance. 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. The annual generation of Hoover Dam varies. The maximum net generation was 10.348 TWh in 1984, and the minimum since 1940 was 2.648 TWh in 1956. The average power generated
7632-425: The possibility of the river's flooding a site at which two thousand men might be at work, and their specifications were covered in the bid documents in nearly as much detail as the dam itself. The upper cofferdam was 96 ft (29 m) high, and 750 feet (230 m) thick at its base, thicker than the dam itself. It contained 650,000 cubic yards (500,000 m ) of material. When the cofferdams were in place and
7738-531: The potential for uneven cooling and contraction of the concrete posed a serious problem. Bureau of Reclamation engineers calculated that if the dam were to be built in a single continuous pour, the concrete would take 125 years to cool, and the resulting stresses would cause the dam to crack and crumble. 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. Each five-foot form contained
7844-476: The powerhouse was carried out simultaneously with the excavation for the dam foundation and abutments. The excavation of this U-shaped structure located at the downstream toe of the dam was completed in late 1933 with the first concrete placed in November 1933. Filling of Lake Mead began February 1, 1935, even before the last of the concrete was poured that May. The powerhouse was one of the projects uncompleted at
7950-491: The proposed dam. The Colorado River Board found the project feasible, but warned that should the dam fail, every downstream Colorado River community would be destroyed, and that the river might change course and empty into the Salton Sea. The Board cautioned: "To avoid such possibilities, the proposed dam should be constructed on conservative if not ultra-conservative lines." On December 21, 1928, President Coolidge signed
8056-728: The railroad causeway that spanned across the Great Salt Lake in Utah. The Lucin Cutoff causeway allowed trains to operate at full operating speeds instead of the slower speeds required to safely travel over the deteriorating wooden trestle crossing parallel to it. The causeway is estimated to have used 65 million tons of rock and gravel. In the 1950s it was involved in the construction of the Rimutaka Tunnel in New Zealand,
8162-401: The remaining rubble. In 1922, after considering it for several years, the Reclamation Service finally rejected the proposal, citing doubts about the unproven technique and questions as to whether it would, in fact, save money. In 1922, the Reclamation Service presented a report calling for the development of a dam on the Colorado River for flood control and electric power generation. The report
8268-411: The reservoir and flood conditions. The gates cannot entirely prevent water from entering the spillways but can maintain an extra 16 ft (4.9 m) of lake level. Apoera-Bakhuys Railway The Republic of Suriname ( Dutch : Republiek Suriname ) has a number of forms of transport. Transportation emissions are an increasing part of Suriname's contributions to climate change , as part of
8374-403: The river in the hope of building a 40-foot (12 m) rock dam which could generate 10,000 horsepower (7,500 kW). 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. Edison allowed land options it held on the river to lapse—including an option for what became the site of Hoover Dam. In
8480-505: The same time dumping rubble into the river until its natural course was blocked. Following the completion of the dam, the entrances to the two outer diversion tunnels were sealed at the opening and halfway through the tunnels with large concrete plugs. The downstream halves of the tunnels following the inner plugs are now the main bodies of the spillway tunnels. The inner diversion tunnels were plugged at approximately one-third of their length, beyond which they now carry steel pipes connecting
8586-410: The sidewalls. Finally, using pneumatic guns, the overheads were filled in. The concrete lining is 3 feet (1 m) thick, reducing the finished tunnel diameter to 50 ft (15 m). The river was diverted into the two Arizona tunnels on November 13, 1932; the Nevada tunnels were kept in reserve for high water. This was done by exploding a temporary cofferdam protecting the Arizona tunnels while at
8692-504: 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
8798-477: The situation. It found that the work had been incompletely done, and was based on less than a full understanding of the canyon's geology. New holes were drilled from inspection galleries inside the dam into the surrounding bedrock. It took nine years (1938–47) under relative secrecy to complete the supplemental grout curtain. The first concrete was poured into the dam on June 6, 1933, 18 months ahead of schedule. Since concrete heats and contracts as it cures,
8904-673: The summer of 1931 was especially torrid, with the daytime high averaging 119.9 °F (48.8 °C). Sixteen workers and other riverbank residents died of heat prostration between June 25 and July 26, 1931. The Industrial Workers of the World (IWW or "Wobblies"), though much-reduced from their heyday as militant labor organizers in the early years of the century, hoped to unionize the Six Companies workers by capitalizing on their discontent. They sent eleven organizers, several of whom were arrested by Las Vegas police. On August 7, 1931,
9010-442: The supervising architect to the Bureau of Reclamation, was brought in to redesign the exteriors. Kaufmann greatly streamlined the design and applied an elegant Art Deco style to the entire project. He designed sculpted turrets rising seamlessly from the dam face and clock faces on the intake towers set for the time in Nevada and Arizona—both states are in different time zones, but since Arizona does not observe daylight saving time ,
9116-475: The time of the formal dedication on September 30, 1935; a crew of 500 men remained to finish it and other structures. 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. In the latter half of 1936, water levels in Lake Mead were high enough to permit power generation, and
9222-417: The top of the canyon with ropes, the high-scalers climbed down the canyon walls and removed the loose rock with jackhammers and dynamite . Falling objects were the most common cause of death on the dam site; the high scalers' work thus helped ensure worker safety. One high scaler was able to save a life in a more direct manner: when a government inspector lost his grip on a safety line and began tumbling down
9328-545: The war, MK expanded into a variety of international construction fields. MK won contracts for many domestic and foreign Cold War projects. It built the locks on the St. Lawrence Seaway , the Distant Early Warning Line system, also known as the DEW Line or Early Warning Line, Minuteman missile silos, NASA ’s Kennedy Space Center , and over 100 major dams. In 1946, King Mohammad Zahir Shah and
9434-586: The waterway, an amount it hoped in vain that it would be reimbursed for by the federal government. Even after the waterway was stabilized, it proved unsatisfactory because of constant disputes with landowners on the Mexican side of the border. As the technology of electric power transmission improved, the Lower Colorado was considered for its hydroelectric -power potential. In 1902, the Edison Electric Company of Los Angeles surveyed
9540-674: The workers. 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. The company built bunkhouses, attached to the canyon wall, to house 480 single men at what became known as River Camp. Workers with families were left to provide their own accommodations until Boulder City could be completed, and many lived in Ragtown. The site of Hoover Dam endures extremely hot weather, and
9646-432: Was 4.2 TWh/year for 1947–2008. In 2015, the dam generated 3.6 TWh. The amount of electricity generated by Hoover Dam has been decreasing along with the falling water level in Lake Mead due to the prolonged drought since year 2000 and high demand for the Colorado River's water. By 2014 its generating capacity was downrated by 23% to 1592 MW and was providing power only during periods of peak demand. Lake Mead fell to
9752-623: Was a 20-year-old concrete superintendent for the Reclamation Service ; Knudsen was a forty-something Nebraska farmer (and Danish immigrant) with a team of horses and a fresno scraper . Their first venture together was in 1912, on a pump plant in nearby Grand View for $ 14,000; they lost money but gained experience. MK earned some revenue in 1914, when they constructed the Three Mile Falls Diversion Dam, south of Umatilla, Oregon . For several years,
9858-418: Was a visitor to the site; the remainder were employees of various contractors not part of Six Companies. Ninety-six of the deaths occurred during construction at the site. Not included in the official number of fatalities were deaths that were recorded as pneumonia . Workers alleged that this diagnosis was a cover for death from carbon monoxide poisoning (brought on by the use of gasoline-fueled vehicles in
9964-446: Was awarded two patents for their design. These buckets, which weighed 20 short tons (18.1 t; 17.9 long tons) when full, were filled at two massive concrete plants on the Nevada side, and were delivered to the site in special railcars . The buckets were then suspended from aerial cableways which were used to deliver the bucket to a specific column. As the required grade of aggregate in the concrete differed depending on placement in
10070-729: Was completed. In 1991, MK purchased a 49% shareholding in New Zealand construction contractor McConnell Dowell . By the 1990s, Morrison–Knudsen had been led into some risky non-core areas by Boise native William Agee , who became CEO in 1988 and was ousted by the board of directors in February 1995. MK had announced a loss of $ 310 million for fiscal year 1994, and a leak of an intended Agee resignation drew broad media attention which resulted in Agee resigning earlier than originally planned. The company had been in financial difficulty for several years, and declared bankruptcy that same year. It
10176-464: Was established for surveyors and other personnel near the dam site; this soon became surrounded by a squatters' camp. Known as McKeeversville, the camp was home to men hoping for work on the project, together with their families. Another camp, on the flats along the Colorado River, was officially called Williamsville, but was known to its inhabitants as "Ragtown". When construction began, Six Companies hired large numbers of workers, with more than 3,000 on
10282-570: Was formed so that Morrison–Knudsen could divest itself of this loss-making division, while also allowing the remaining MK Transit contracts to be completed. The new company was funded by Morrison–Knudsen's creditors, led by the Fidelity and Deposit Company in Baltimore , and was headquartered in Chicago . The Pittsburg site was transferred to Adtranz in December 1995, following completion of
10388-429: Was imminent, most workers took their paychecks and left for Las Vegas to await developments. Two days later, the remainder were talked into leaving by law enforcement. On August 13, the company began hiring workers again, and two days later, the strike was called off. While the workers received none of their demands, the company guaranteed there would be no further reductions in wages. Living conditions began to improve as
10494-402: Was nearly 16,000 ft, or more than 3 miles (5 km). The contract required these tunnels to be completed by October 1, 1933, with a $ 3,000-per-day fine to be assessed for any delay. 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. Tunneling began at the lower portals of
10600-480: Was principally authored by Davis and was called the Fall-Davis report after Interior Secretary Albert Fall . 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. Though the Fall-Davis report called for a dam "at or near Boulder Canyon", the Reclamation Service (which was renamed the Bureau of Reclamation
10706-585: Was purchased by Washington Group in 1996 for $ 380 million. For several years after the 1996 merger, the company continued as Morrison–Knudsen. Growth by acquisition brought it into the top tier (by size) of American construction firms. In 1999, MK acquired the government-services operations of Westinghouse Electric Company , becoming a science and technology services leader. The company expanded its market leadership in 2000 by acquiring Raytheon Engineers & Constructors, which owned engineering giant Rust International of Birmingham, Alabama , to produce one of
10812-488: Was removed. Since the dam was an arch-gravity type, the side-walls of the canyon would bear the force of the impounded lake. Therefore, the side-walls were also excavated to reach virgin rock, as weathered rock might provide pathways for water seepage. Shovels for the excavation came from the Marion Power Shovel Company . The men who removed this rock were called "high scalers". While suspended from
10918-430: Was signed on November 24, 1922. Legislation to authorize the dam was introduced repeatedly by two California Republicans, Representative Phil Swing and Senator Hiram Johnson , but representatives from other parts of the country considered the project as hugely expensive and one that would mostly benefit California. The 1927 Mississippi flood made Midwestern and Southern congressmen and senators more sympathetic toward
11024-480: 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. 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. Instead, Wilbur announced in early 1930 that
11130-509: 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
11236-419: Was to provide the materials, and the contractor was to prepare the site and build the dam. The dam was described in minute detail, covering 100 pages of text and 76 drawings. A $ 2 million bid bond was to accompany each bid; the winner would have to post a $ 5 million performance bond . The contractor had seven years to build the dam, or penalties would ensue. The Wattis Brothers , heads of
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