Boulder Dam - 1937
US National Archives・2 minutes read
The construction of Boulder Dam in the Colorado River involved extensive planning, meticulous execution, and the use of advanced machinery to divert the river and build the dam, which was completed ahead of schedule in 1935. President Franklin Delano Roosevelt dedicated the dam to the progress of the nation, highlighting its significance as a key infrastructure project with a large power plant, intake towers, and a reservoir named Lake Mead.
Insights
- The construction of Boulder Dam, authorized by the Boulder Canyon Project Act of 1928, involved meticulous planning and execution, including the transportation of materials from across the country, meticulous rock preparation, and advanced concrete mixing processes.
- Boulder Dam, completed ahead of schedule in June 1935, stands as a monumental achievement, featuring a roadway on its crest as part of a transcontinental highway, a vast reservoir named Lake Mead, and a powerhouse with seventeen generating units capable of producing 1,835,000 horsepower of electrical energy.
Get key ideas from YouTube videos. It’s free
Recent questions
How long is the Colorado River?
1,700-mile course through the arid Southwest
What was the purpose of the Boulder Canyon Project Act of 1928?
Authorized the construction of Boulder Dam
How long did it take to build Boulder City?
Built in fifteen months to house 5,000 workers
What materials were used in the construction of Boulder Dam?
Steel, cement, machinery, and tools
How was concrete transported during the construction of Boulder Dam?
Using motor trucks and electric trains
Related videos
Summary
00:00
Building Boulder Dam: A Monumental Engineering Feat
- The Colorado River has a 1,700-mile course through the arid Southwest, draining a vast region and entering seven western states before flowing into the Gulf of California.
- The Boulder Canyon Project Act of 1928 authorized the construction of Boulder Dam in Black Canyon, Nevada and Arizona, by the United States Department of the Interior.
- Boulder City was built in fifteen months to house 5,000 workers, providing modern facilities, churches, schools, and recreational amenities.
- Construction materials like steel, cement, machinery, and tools were transported to the site from all over the country.
- The construction involved the excavation of diversion tunnels, lined with concrete, to redirect the river during construction.
- Roads and rail lines were built into the canyon to facilitate transportation of materials and workers.
- The construction involved blasting rock from the canyon walls, creating foundations for the dam and power plant.
- Sand and gravel for concrete were obtained from a deposit upstream, screened, washed, and transported to mixing plants at the dam site.
- Concrete was mixed in two plants equipped with advanced machinery, using a system of conveyor belts and railroads for material transportation.
- Meticulous care was taken in preparing rock surfaces for concrete placement, ensuring the stability of the dam's foundation.
15:23
"Boulder Dam: Efficient Concrete Mixing Operations"
- The high level mixing plant at Boulder Dam operated every three and one-half minutes, with automatic equipment controlling concrete ingredients and recording operations.
- An operator on the control deck directed the mixing cycle, with mechanical equipment selecting, measuring, and weighing materials for precise mixes.
- Water was added in controlled amounts to the concrete mix, which was thoroughly agitated to withstand the dam's pressure.
- Concrete was dispatched using motor trucks and electric trains, with various containers like eight cubic yard buckets and four cubic yard transit mixers.
- A system of nine aerial cableways transported concrete and materials from train or truck delivery points to the dam and other structures.
- The first bucket of concrete was placed in the dam forms on June 6, 1933, marking the beginning of the dam's construction.
- Concrete was placed in keyed columns, with expert crews handling equipment for record-breaking daily pours.
- Steel penstock pipes for the power and pressure outlet systems were fabricated and installed by the Babcock & Wilcox Company.
- Pipe sections were transported to the dam site using a special road trailer capable of carrying 200 tons, with a 200-ton capacity cableway used for lowering them into the canyon.
- The dam structure was completed in June 1935, two and a half years ahead of schedule, with the penstock pipes forming continuous conduits between intake towers and the powerhouse.
30:37
Roosevelt dedicates Boulder Dam, world's largest
- President Franklin Delano Roosevelt dedicated Boulder Dam to the progress of the nation, praising the designers and builders. The dam, now completed, features a roadway on its 1300-foot crest, forming part of a transcontinental highway. The reservoir behind the dam, named Lake Mead in memory of Doctor Elwood Mead, extends 115 miles upstream, with a shoreline of 550 miles, offering new vistas as the water gradually rose.
- Boulder Dam's four intake towers, equipped with cylindrical gates, serve as inlets to steel penstocks supplying water to turbines and outlet valves. The dam's power plant, with seventeen generating units, is the world's largest, capable of producing 1,835,000 horsepower of electrical energy. Transmission lines from the dam, particularly to Los Angeles, showcase advanced power transmission technology.
