Water and Power Associates
Water and Power Associates
(1930)* - Black Canyon - The future site of Hoover Dam.
 
 
Background
Hoover Dam was constructed between 1931 and 1936 during the Great Depression. Its main purpose was to harness the Colorado River to prevent periodic catastrophic flooding,  to  allocate and distribute water,  and to generate hydroelectricity for the Southwest. Even by today's standards Hoover Dam   was a gigantic project. At the time it was the world's largest project made with   concrete, not to mention the largest public works project in US history.
The dam's completion  had a significant impact on Southern California and in particular Los Angeles, since the power generated by the dam contributed to more than 70% of the City's power needs at the time.
 
 
 
(1925)^* - "The Party" about  to embark for a trip through Boulder Canyon. They are assessing the potential sites for a dam on the Colorado River.
 
 
Historical Notes
Members  of a water resources consulting committee (F. E. Bonner, A. J. Cleary, G. A.  Elliot, B. A. Etcheverry, F. C. Herrmann, Louis C. Hill, W. L. Huber, A.  Kempkey, J. B. Lippincott, William Mulholland, and C.S. Ridley) prepare to  embark on a trip down the Colorado river, through Boulder Canyon, with representatives  of the City of Los Angeles (William Mullholland, H. A. Van Norman, E. A.  Bayley, H. C. Gardett, and S. Parratt) and the State of California (Paul Bailey  and Gerald Jones).^*
More  than 200 engineers worked to design the dam that would be constructed in Black  Canyon. It would be the highest concrete arch dam in the United States, and the  largest building project that the federal government had ever undertaken.*#
 
 
Historical Notes
Before  a dam could be built, political work was necessary to resolve the competing  claims on the river by different western states. As U.S. secretary of commerce,  Herbert Hoover negotiated the Colorado River Compact, which divided the river  basin into two regions, lower (Arizona, Nevada and California) and upper  (Wyoming, Utah, New Mexico and Colorado) that would make the building of the  dam possible.
In  1928, after years of lobbying to get a dam-building bill through Congress, the  legislation was finally approved as the Boulder Canyon Project Act. Hoover,  who that same year was elected as the 31st president of the United States,  signed the bill into law in 1929.*#
 
 
 
 
Historical Notes
Construction    efforts consisted of re-routing the river through canyon walls, blasting    immense amounts of rock and dredging efforts to build on a bedrock    foundation, construction of two diversion coffer dams, and pouring 6.6    million tons of concrete.
More  than 8.5 million pounds of dynamite was used to blast the foundation for the  dam and 8 miles of tunnels through the canyon walls. #*
 
 
 
(ca. 1931)^^ -  Workmen supported by lines from the top as they did high scaling on canyon  walls during construction of the dam.
 
 
Historical Notes
“High  Scalers” climbed down canyon walls on ropes to remove loose and weakened rocks  along the canyon walls where the dam walls would join. Descending down the  cliffs with the weight of tools, water and food, others would lower jackhammers  to drill powder holes. The High Scalers would fill the holes with dynamite and  after hand maneuvering out of the way of explosives, they went to work with  crowbars to remove loosened rock.*^*
 
 
 
(1932)* -  View  from above the Colorado River looking upstream towards the site of Hoover Dam  which is at the bend in the river. On the right we can see the lower portals of  the Arizona water diversion tunnels.
 
 
Historical Notes
Before construction could begin, the river was diverted around the dam site through four 50-foot-diameter            tunnels, two  drilled through the canyon            walls on each side of the river. The tunnels, with a total combined length of 15,946 feet, or about three            miles, were excavated to 56 feet and lined with three feet (300,000            cubic yards) of concrete. They could carry over 200,000 cubic            feet - more than 1.5 million gallons - of water per second. The river            was first diverted through the two Arizona tunnels on November 14, 1932.*#^
 
 
Historical Notes
The  Jumbo Rig was designed to speed up the Hoover Dam's tunnel drilling process.  Built on the back of a 10-ton truck, 24 to 30 drills could be operated at once.^
These jumbos had two  platforms for drillers to stand on, the third level of men working from the  ground.  It also had horizontal bars at  the three levels, where the pneumatic drills hung by swivels.  The process then became: Back the truck up to  the solid rock wall, drill the holes, pack them with dynamite, tie them  together and then pull the entire truck a safe distance away while the blowman  detonated.  Then clear away the debris  and do it again.*#*
 
 
 
(1932)**^ –  View showing the interior of one of the  tunnels through which the Colorado River will be diverted around the Hoover Dam  site.,  April 18, 1932.
 
 
 
(ca. 1933)^#^ - Government officials and politicians take a ride in one of the 30 ft. diameter pipe sections.
 
 
Historical Notes
Forty-four  thousand tons of steel were formed and welded into 14,800 feet of pipe varying  from 8 1/2 to 30 feet in diameter. Each length of the largest pipe - 12 feet  long, 30 feet in diameter, and 2 3/4 inches thick - was made from 3 steel  plates, of such weight that only two plates could be shipped from the steel  mill to the fabricating plant on one railroad car. Two such lengths of pipe  welded together make one section weighing approximately 135 tons or, at  intersections with the penstocks, as much as 186 tons.^*^
 
 
 
Workmen stand in completed spillway tunnel lining at Boulder Dam.* The spillway tunnel is 50 feet in diameter and 2,200 feet in length. Click HERE to view a detail diagram showing Boulder Dam's piping and penstock configuration.
 
 
Historical Notes
Each of the 4 diversion tunnels was  holed out to 56-foot diameter—as high as a 4-story building—and lined with a  3-foot thickness of concrete. The total length of the tunnels was approximately  3 miles.**#
 
 
 
(1934)* -  Five workmen  peer at the inside one of the four diversion tunnels. Behind them on the right is another  tunnel.
 
 
Historical Notes
The four tunnels  would have another important use besides diversion of the river. After  completion of the dam, they would serve to house the outlet works used in the  regulation of the reservoir. The two outer tunnels would become outlets for the  huge spillways. The two inner tunnels would guide the stored water from the  intake towers in the reservoir to the power plant or past it to the outlet  valves below the dam.**#
 
 
 
(ca. 1933)^^ - Construction was a 24/7 operation. In this  view we can see the base of the dam face on the far side of a pool of water,  construction equipment and night lights.
 
 
Historical Notes
The  first concrete was poured into the dam on June 6, 1933, 18 months ahead of  schedule.^
 
 
 
(ca. 1933)* - Hoover Dam initial construction phase. Note the width and depth of the dam as it goes up.
 
 
Historical Notes
Since  concrete heats and contracts as it cures, the potential for uneven cooling and  contraction of the concrete posed a serious problem. Bureau of Reclamation  engineers calculated that if the dam was 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 was to rise was  marked with rectangles, and concrete blocks in columns were poured, some as  large as 50 feet square and 5 feet high.^
 
Every  state in the USA furnished supplies and materials for the construction of the  dam. #*
 
 
 
(ca. 1934)* - A closer look at the cement forms for the two power plants. Construction workers can be seen throughout.
 
 
Historical Notes
There  were 112 deaths associated with the construction of the dam. Included in that  total was J. G. Tierney, a surveyor who drowned on December 20, 1922, while  looking for an ideal spot for the dam. He is generally counted as the first man  to die in the construction of Hoover Dam. His son, Patrick W. Tierney, was the  last man to die working on the dam's construction, 13 years to the day later. Ninety-six  of the deaths occurred during construction at the site of the 112 fatalities^.... None were buried in the concrete.  #*
 
 
 
(1934)#*  - View of three men standing by a Packard observing the near completed process of  concrete pouring at the dam.
 
 
 
(1935)* - View of the Hoover Dam power plants near completion. The concrete pouring process appears to be complete.
 
 
Historical Notes
A total  of 3,250,000 cubic yards of concrete was used in the dam before concrete  pouring ceased on May 29, 1935. In addition, 1,110,000 cubic yards were used in  the power plant and other works. More than 582 miles of cooling pipes were  placed within the concrete. Overall, there is enough concrete in the dam to  pave a two-lane highway from San Francisco to New York.^
 
 
 
(ca. 1935)* - View of the giant turbine runner before its installation at Hoover   Dam power plant. The fin-like pieces of metal between the two circular flanges   are the vanes.
 
 
 
(September 30, 1935)* - Dedication of Hoover Dam by President F. D. Roosevelt. Ezra Scattergood can be seen in the lower right behind the chair with the hat.
 
 
Historical Notes
On September 30, 1935, less than 5 years after construction  started, President Franklin D. Roosevelt said in dedication ceremonies at  Hoover Dam: “This is an engineering victory  of the first order – another great achievement of American resourcefulness,  skill and determination. This is why I congratulate you who have created  Boulder Dam and on behalf of the Nation say to you, ‘well done’.” ^##
In 1920, Ezra Scattergood pushed for a bill  authorizing the construction of the Boulder Canyon Project (Hoover Dam).  Despite attempts to discredit the project, Scattergood helped convince Congress  in 1928 to pass the legislation and allow construction of the dam and a  hydroelectric power plant.^#
 
 
 
(1936)**^ – A crowd is assembled in the power house of the Hoover  Dam in Boulder City, Nev., during ceremonies in which U.S. President Franklin  Roosevelt pressed a button in Washington, D.C., starting the 3,500 horsepower  generator in the foreground, creating the first power from the dam in Boulder  City, September 11, 1936.
 
 
Historical Notes
The City of Los Angeles would have to wait another 28 days (October 9th, 1936) before it would get its allotment of power from Hoover Dam.
 
 
 
(1930s)**^ – View showing the high-voltage  switching yard at Boulder Dam, with the steel etched against a black desert sky.  Power from the generators at the top of  Boulder Dam left this station on the main line to Los Angeles at 287,500 volts.
 
 
Historical Notes
Sixteen high-voltage transmission lines connect Hoover Dam  with its power market area.  Two lines  terminate at Los Angeles, a line a distance of 266 miles.  A third line extends to Los Angeles via the  McCullough Switching Station, where the energy is stepped up to 500,000 volts.  One line extends to San Bernardino,  California.  Three lines extend to Las  Vegas, Nevada.  One of the latter  connects with the Davis Dam transmission system.  Other lines extend to Kingman, Arizona;  Needles, California and nearby Boulder City.^^#
In total, there are 2700 miles of transmission line cable sending    electricity from Hoover Dam to Los Angeles. #*
Click HERE to see more in Early Power Transmission.
 
 
 
(October 9, 1936) - Plaque reads: "On the above date Miss Elisabeth Scattergood pressed this key which lighted the electric arc in the Civic Center as the citizens of Los Angeles received their first electric power from the Hoover Dam Hydro Electric Plants of the Colorado River".
 
Construction of Hoover Dam Video
Click HERE to view video.
 
 
Construction of Hoover Dam - Historical Timeline
The following timeline takes us from the late 1890’s when  the first attempt to control flooding from the Colorado River began to 1936 when  the Hoover Dam was completed and electric power flowed to the City of Los Angeles:
1890’s – Initial attempt at diverting the Colorado River for  irrigation purposes by the construction of the Alamo Canal by land speculator  William Beatty.
1900 – Preliminary investigation and studies for building a  dam at Black Canyon or Boulder Canyon with the purpose of controlling floods,  providing irrigation water, and producing hydroelectric power.  Repeated flooding of the Imperial Valley and  other areas created the need to control the Colorado River through construction  of a dam.
1902 – Edison Electric Company surveys the Colorado River  with the idea of building a 40-foot rock dam which could generate 10,000  horsepower.  At this time, however, the  limit for transmission of electric power is only 88 miles and there are few  customers within that limit.  During that same  year Edison allows its land options on the river to lapse, including an option  for what became the site of Hoover Dam.
1902 - U.S. Congress passes the Reclamation Act to provide for a plan for the payment of construction costs for a reclamation project to control the Colorado River.
1905 – Heavy rainfall and snowmelt causes the Colorado River  to swell and overrun a set of Alamo Canal head-gates.  This results in a flood which diverts the  entire volume of the Colorado River  into the Salton Sink over a period of  approximately two years before it can be controlled again.  This catastrophic event also floods the entire  Imperial Valley.  The flood completely submerges the town of  Salton, Southern Pacific Railroad siding, and Torres-Martinez Indian land.  The Salton Sea is created as a result of   the diverted uncontrolled flow of the Colorado River  over 50 miles into what was once an ancient dry lakebed in the desert for over two  years without drainage.
1906-1907 – Southern Pacific Railroad spends $3 million to  stabilize the waterway.
1922 – Reclamation Service (later the Bureau of Reclamation)  presents a report calling for building a dam on the Colorado for flood control  and power generation.  The report  concludes that this should become a federal project since the river’s basin covers  several states and  the river  enters Mexico.
1922- Reclamation Service selects Black Canyon as the ideal  spot for the dam not the original location of Boulder Canyon since that site is  bisected by a fault-line. The name of the project remains ‘Boulder Canyon Project’  despite the site change (See above photo).
1922 – The Colorado River Compact is signed by seven states  of the Colorado basin (California, Nevada, Arizona, Utah, new Mexico, Colorado  and Wyoming.  More than anything this  serves to balance each of the affected state’s water rights.
1926 - William Mulholland gets involved with the Boulder Canyon Project even when funding wasn't clearly available. He makes a commitment to Congress to buy even more power than needed by Los Angeles.  The extra power would be used to pump water in a newly planned aqueduct that would bring Colorado River water to Southern California (Colorado Aqueduct, completed 1941). Los Angeles guarantees its power purchases against the federal government's costs for the dam.
1928 – Congress authorizes the project and President  Coolidge signs the bill.  $165 million is  appropriated for the Hoover Dam, the Imperial Dam and the All-American Canal, both downstream. Legislation to authorize construction of the dam has taken years since  representatives from other parts of the country found it to be too costly and  beneficial to mostly California.  Not  until the 1927 Mississippi flood did Midwestern and Southern congressmen and  senators become more sympathetic to the dam project.
1929 – Six of the seven states approve the compact which is the  minimum required to proceed with the project.   Arizona does not approve until 1944.
1931 – Start of Construction by a consortium of companies  called Six Companies, Inc.
1933 - Ezra Scattergood obtains a  $22,799,000 loan from  the federal government to build a power transmission line from Hoover Dam to Los Angeles. Construction of the Boulder-LA transmission line begins as the dam itself is erected.
1934 - Congress authorizes a fifty-year contract that defines the how the Hoover Dam's electricity is to be allocated and sold, which would run from 1937 - 1987. The authorization also defines who is to operate the powerhouses within that  time frame--both the Los Angeles Department of Water and Power and Southern California Edison. In 1984 the allocation of power would be revised (see 'Current Milestones' below). Also, in 1987 the Bureau of Reclamation assumes control of the powerhouses.
1935 (September 30) – Hoover Dam is dedicated by President  Franklin Roosevelt.
1936 (March 1st) – The dam is turned over to the  federal government from Six Companies, more than two years ahead of schedule.
1936 (October 9th) – Hoover Dam begins  transmitting electricity to Los Angeles. The DWP built transmission line spans 266 miles  of mountains and desert and delivers over 70% of Los Angeles’ power (Hoover Dam delivers less than 6% of LA's power today). The transmission lines included pioneering technology in high-voltage transmission. They transmitted electricity at a higher voltage (287 kV) than any other long-distance transmission line in the world to date.
 
 
The Naming Controversy: Boulder Dam or Hoover Dam?
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. The Boulder Canyon Project Act of 1928 (BCPA) never mentions a  proposed name or title for the dam. The BCPA merely allows the government to "construct, operate, and maintain a dam and incidental works in the main  stream of the Colorado River at Black Canyon or Boulder Canyon".
When Secretary  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. Wilbur justified his choice on  the ground that Hoover was "the great engineer whose vision and  persistence ... has done so much to make [the dam] possible".  One writer complained in response that "the Great Engineer had quickly drained, ditched, and dammed the  country".
After Hoover's  election defeat in 1932 and the accession of the Roosevelt administration,  Secretary Ickes ordered on May 13, 1933 that the dam be referred to as "Boulder Dam". Ickes stated that Wilbur had been imprudent in naming  the structure after a sitting president, that Congress had never ratified his  choice, and that it had long been referred to as Boulder Dam.  When Ickes spoke at the dedication ceremony  on September 30, 1935, he was determined, as he recorded in his diary, "to  try to nail down for good and all the name Boulder Dam".  At one point in the speech, he spoke the words "Boulder Dam" five times within thirty seconds.  Further, he suggested that if the dam were to  be named after any one person, it should be for California Senator Hiram  Johnson, a lead sponsor of the authorizing legislation.  Roosevelt also referred to the dam as Boulder  Dam, and the Republican-leaning Los Angeles Times, which at the time of Ickes'  name change had run an editorial cartoon showing Ickes ineffectively chipping  away at an enormous sign "HOOVER DAM", reran it showing Roosevelt reinforcing Ickes, but having no greater success.
In the following years, the name "Boulder  Dam" failed to fully take hold, with many Americans using the two names  interchangeably and mapmakers divided as to what name should be printed.  Memories of the Great Depression faded, and Hoover to some extent rehabilitated  himself through good works during and after World War II. In 1947, a bill  passed both Houses of Congress unanimously restoring the name to "Hoover  Dam". 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."^
 
 
More Recent Milestones
1984 - Congress passes a new statute which sets power allocations from the dam for the period  1987 to 2017.
1987 - The Bureau of Reclamation assumes control of running the powerhouses. Both DWP and SCE operated the powerhouses between 1936 and 1987.
2011 - President Obama signs legislation extending the power allocation 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 is to take place in 2017.^
 
 
Boulder Dam-LA Transmission Line
Click HERE for the Boulder Dam-LA Transmission Line Engineering Paper  by E. F. Scattergood, presented to the American Institute of Electrical Engineers in 1935.