Stretching enough concrete to pave a highway from San Francisco to New York City, Hoover Dam stands as a breathtaking monument to the 21,000 workers who poured their labor into its massive arch-gravity design during the Great Depression.
Key Takeaways
- Hoover Dam was constructed between 1931 and 1936, taking 5 years to complete ahead of schedule.
- The dam required 3,250,000 cubic yards of concrete, equivalent to a 2-lane highway from San Francisco to New York City.
- Over 21,000 workers were employed at peak construction, with a workforce averaging 5,251 men daily.
- The dam's base is 660 feet thick, tapering to 45 feet at the crest.
- Hoover Dam's crest length is 1,244 feet (379 meters) across the top.
- The structural height from riverbed to crest is 726.4 feet (221.3 meters).
- The Hoover Dam generates up to 2,080 megawatts of power.
- Annual energy production averages 4.2 billion kilowatt-hours.
- Seventeen main turbines produce 680 MW each in the Nevada wing.
- Lake Mead holds 28.23 million acre-feet at capacity.
- Maximum water surface elevation is 1,229 feet above MSL.
- Minimum power pool elevation is 1,050 feet.
- Hoover Dam cost $49 million to build, repaid by power revenues by 1987.
- Annual power revenues average $150 million since 2000.
- The dam enabled $1 trillion in economic activity since 1936.
Hoover Dam was a massive engineering project completed ahead of schedule during the Great Depression.
Construction History
- Hoover Dam was constructed between 1931 and 1936, taking 5 years to complete ahead of schedule.
- The dam required 3,250,000 cubic yards of concrete, equivalent to a 2-lane highway from San Francisco to New York City.
- Over 21,000 workers were employed at peak construction, with a workforce averaging 5,251 men daily.
- Construction cost $49 million in 1935 dollars, equivalent to about $1.1 billion in 2023 adjusted dollars.
- The Hoover Dam project was authorized by the Boulder Canyon Project Act of 1928 signed by President Coolidge.
- Six companies formed the Six Companies, Inc. consortium that won the bid to build the dam for $48.8 million.
- Diversion tunnels during construction totaled 15,000 feet in length, with diameters of 56 feet.
- Cooling coils totaling 582 miles were embedded in the concrete to control heat from curing.
- The first concrete was poured on June 6, 1933, and the last on May 29, 1935.
- High scalers removed 1.2 million cubic yards of sandstone from the canyon walls using jackhammers.
- 96 workers died during construction, with the last fatality on December 20, 1935.
- The upstream face was completed first on March 1, 1935, followed by the downstream face.
- President Franklin D. Roosevelt dedicated the dam on September 30, 1935.
- The dam was initially called Boulder Dam, renamed Hoover Dam in 1947 by President Truman.
- Cableways spanning 650 feet transported materials, each capable of lifting 20 tons.
- 4.4 million cubic yards of rock and earth were excavated for the foundation.
- The project generated over 3.5 million man-hours of labor during construction.
- Refrigeration plants produced aggregate chilled to 32°F for concrete mixing.
- The dam's construction halted the Colorado River flow for the first time in history.
- Black Canyon site was selected over Boulder Canyon due to better foundation rock.
- Initial workforce lived in Ragtown shantytown before Boulder City was built.
- Boulder City was constructed as a model city for 5,000 workers and families.
- The dam used 19.6 million pounds of structural steel and 300 miles of pipe.
- First power was generated October 9, 1936, with full capacity by 1947.
- The Colorado River Aqueduct construction paralleled the dam project.
- Hoover Dam's design is an arch-gravity type, pioneered by U.S. engineers.
- The project was completed under budget by $5 million.
- 2,000 miles of two-wire line telephone system supported construction communications.
Construction History Interpretation
This gargantuan feat of Depression-era ambition, built by thousands of men who literally moved mountains and chilled their own concrete, stands not just as a marvel of engineering but as a testament to the staggering human calculus where monumental achievement is soberly measured in both billions of modern dollars and 96 individual lives.
Economic and Visitor Stats
- Hoover Dam cost $49 million to build, repaid by power revenues by 1987.
- Annual power revenues average $150 million since 2000.
- The dam enabled $1 trillion in economic activity since 1936.
- Boulder City population grew to 15,000 due to dam workers.
- Visitor center attracts 1 million tourists annually pre-COVID.
- Dam tours generate $10 million in fees yearly.
- Power allocations worth $4 billion annually to users.
- Construction paid $66 million in wages over 5 years.
- Lake Mead recreation contributes $1.5 billion to economy yearly.
- Dam supports 40,000 jobs in water and power sectors.
- Visitor numbers peaked at 1.7 million in 2015.
- The project irrigated 2 million acres of farmland.
- Power enabled aluminum production during WWII.
- Annual tourism spend at dam site is $400 million.
- Dam bonds repaid with interest totaling $56 million by 1952.
- Hoover Dam is a National Historic Landmark since 1984.
- Skywalk at nearby Bridge adds $30 million tourism revenue.
- Dam maintenance costs $50 million annually.
- Water deliveries valued at $500 million yearly for agriculture.
- The dam boosted GDP by 0.5% during Great Depression.
- 7 million visitors since tour center opened in 1983.
Economic and Visitor Stats Interpretation
A monument of economic alchemy, Hoover Dam transformed $49 million in concrete into a century of trillion-dollar growth, proving that while you can’t water the desert with money, you can use it to build a machine that does.
Power Production
- The Hoover Dam generates up to 2,080 megawatts of power.
- Annual energy production averages 4.2 billion kilowatt-hours.
- Seventeen main turbines produce 680 MW each in the Nevada wing.
- Nine turbines in the Arizona wing generate 130 MW each.
- Power is distributed to Arizona, California, and Nevada.
- First generator went online August 20, 1939.
- Turbines have a head of 530 feet and flow of 68,000 cfs max.
- Annual revenue from power sales exceeds $100 million.
- The dam supplies 28% of Nevada's total power needs.
- Penstocks are 30 feet diameter steel pipes, 500 feet long.
- Station service units provide 15 MW for plant operations.
- Power plant capacity was upgraded in 1987 to 2,080 MW.
- Generators weigh up to 2.4 million pounds each.
- Annual output powers 1.3 million homes.
- Voltage step-up transformers raise output to 345 kV.
- The plant has 61 single-speed elevators for maintenance.
- Francis-type turbines rotate at 180 RPM.
- Powerplant elevation is 1,000 feet above sea level.
- Emergency generators provide 2.4 MW backup.
- Hoover Dam power fueled Las Vegas' growth post-WWII.
Power Production Interpretation
The Hoover Dam, harnessing the immense energy of a 530-foot water drop with brute-force turbines that could double as small moons, has spent 85 years cranking out billions in revenue and enough power to illuminate the neon heart of Las Vegas while simultaneously keeping the lights on for 1.3 million homes across the Southwest, all from a single concrete plug in the desert.
Structural Dimensions
- The dam's base is 660 feet thick, tapering to 45 feet at the crest.
- Hoover Dam's crest length is 1,244 feet (379 meters) across the top.
- The structural height from riverbed to crest is 726.4 feet (221.3 meters).
- Hydraulic height of the dam is 714 feet (218 meters).
- Crest width averages 45 feet (14 meters), with 8-foot-wide roadway.
- The dam contains 3,250,000 cubic yards (2.5 million m³) of concrete.
- Upstream face radius curves with a 640-foot (200 m) radius.
- Downstream face has a 700-foot (210 m) radius at the base.
- The dam weighs approximately 6.6 million tons.
- Spillway elevations are at 1,176 feet above sea level.
- Power plant wings extend 670 feet upstream from the dam.
- Intake towers rise 395 feet above the riverbed.
- The dam's foundation is embedded 10 feet into bedrock.
- Crest elevation is 1,232 feet above mean sea level.
- Riverbed elevation at dam site is 505 feet above sea level.
- The dam is 660 feet wide at the base.
- Elevator shafts descend 716 feet inside the dam.
- Four government columns on the Arizona side are 30 feet square.
- Wing walls are 520 feet long on the Nevada side.
- The Angel of the River statues are 30 feet high.
- Terrace No. 1 supports the intake towers, spanning 500 feet.
- The dam's profile is a parabolic arch design.
- Concrete blocks were poured in 5-foot lifts, each 50x50x5 ft.
Structural Dimensions Interpretation
Hoover Dam is a masterpiece of engineering where 6.6 million tons of patient concrete, poured five feet at a time, quietly laughs at the Colorado River's past ambitions.
Water Storage and Flow
- Lake Mead holds 28.23 million acre-feet at capacity.
- Maximum water surface elevation is 1,229 feet above MSL.
- Minimum power pool elevation is 1,050 feet.
- Average annual inflow is 10 million acre-feet.
- Diversion tunnels carry 200,000 cfs during floods.
- Lake Mead covers 247 square miles at full pool.
- Hoover Dam supplies water to 25 million people via aqueducts.
- Annual water releases average 9 million acre-feet.
- Spillway stilling basins are 50 feet deep.
- Colorado River flow at dam averages 15,000 cfs.
- Lake Mead dead pool is 895 feet elevation.
- Irrigation deliveries total 1.5 million acre-feet yearly to Arizona.
- The dam controls floods protecting 1 million acres downstream.
- Water temperature is cooled to 55°F before release.
- Central Arizona Project receives 1.6 million acre-feet annually.
- Lake Mead shoreline extends 550 miles.
- Maximum depth of Lake Mead is 532 feet.
- Sediment trap capacity is 1.25 million acre-feet.
- River outflow regulated to 10,000 cfs minimum.
- Hoover Dam provides 90% of Southern Nevada's water.
- Historical low elevation was 1,068 feet in 2022.
- The dam created Lake Mead, largest U.S. reservoir by volume.
- Evaporation losses average 700,000 acre-feet per year.
- Bypass tubes in intakes prevent cavitation damage.
Water Storage and Flow Interpretation
Hoover Dam is a miraculous and slightly terrifying act of human confidence, as we've not only trapped the Colorado River into a lake so vast it loses enough water each year to supply a small state, but we also trust this single concrete plug to control floods, hydrate 25 million people, and keep the lights on, all while the river itself seems to be writing a very dry epilogue.
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