page_title: Glen Canyon Dam
section_title: Concrete placement and completion
hierarchical_section_title: Glen Canyon Dam / Construction / Concrete placement and completion
caption_attribution_description: English: View of Glen Canyon Dam under construction, Arizona, 1962
context_page_description: Glen Canyon Dam is a concrete arch-gravity dam on the Colorado River in northern Arizona, United States, near the town of Page. The 710-foot high dam was built by the U.S. Bureau of Reclamation from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of 27 million acre feet. The dam is named for Glen Canyon, a series of deep sandstone gorges now flooded by the reservoir; Lake Powell is named for John Wesley Powell, who in 1869 led the first expedition to traverse the Colorado's Grand Canyon by boat.
  A dam in Glen Canyon was studied as early as 1924, but these plans were initially dropped in favor of the Hoover Dam which was located in the Black Canyon. By the 1950s, due to rapid population growth in the seven U.S. and two Mexican states comprising the Colorado River Basin, the Bureau of Reclamation deemed the construction of additional reservoirs necessary. Contrary to popular belief, Lake Powell was not the result of negotiations over the controversial damming of the Green River within Dinosaur National Monument at Echo Park; the Echo Park Dam proposal was abandoned due to nationwide citizen pressure on Congress to do so.
context_section_description: With the Colorado River safely diverted around the canyon, construction could begin on the actual concrete arch dam. The contract was given to the Merritt-Chapman & Scott Corporation for an "astoundingly low" $107,955,552, about $30 million less than USBR's own estimate. Then, right before construction began, about 750 workers organized a strike because of a wage reduction due to the completion of public facilities at Page. In December 1959, wages were raised by $4 a day, quelling the strikers. Concrete placement started on June 16, 1960, and started at a sluggish but growing pace. In 1962 the workforce topped out at nearly 2,500 employees laboring on the dam. Construction would ultimately claim eighteen lives and injure numerous other workers, but contrary to popular myth, no workers were buried alive in the concrete. Cement needed to make concrete for the dam came from the Phoenix Cement Company plant constructed for the purpose in Clarkdale, south of Flagstaff.
  A huge concrete plant capable of putting out 1,450 tons per hour was installed, and a pair of cableways with movable towers (with capacities of 50 and 25 tons respectively) spanned the canyon, carrying the 12-cubic-yard (9.2 m³) concrete buckets to their final destinations on the steadily rising crest of the dam. The concrete was poured into modular 7.5-foot (2.3 m) high wooden blocks or "forms", the largest measuring up to 60 feet (18 m) by 210 feet (64 m); more than 3,000 of these blocks made up the main structure of the dam. Once the concrete cured, the wooden scaffolding was removed and shifted upwards to accommodate the next load of concrete. As more efficient methods of concrete pouring were installed, including conveyors and remotely controlled buckets, the workforce gradually decreased. By late 1962, concrete was being poured into the dam at a rate of 8,000 cubic yards (6,100 m³) per day even as the workforce was scaled down to about 1,500.
  At the beginning of 1963, the dam was high enough to begin impounding water; huge steel gates were closed over the right diversion tunnel on January 21, and Lake Powell began to rise. A minimal flow of 1,000 cubic feet per second (28 m³/s) was allowed through the dam, to prevent the Colorado River from drying up completely. On that day, David Brower confronted President John F. Kennedy in a last-ditch effort to delay Glen Canyon's inundation. Brower later said of that exchange: "On January 2, 1963, the last day on which the execution of one of the planet's greatest scenic antiquities could yet have been spared, the man who theoretically had the power to save the place did not. I was within a few feet of his desk in Washington that day and witnessed how the forces long at work had their way. So a steel gate dropped, choking off the flow of the canyon's carotid artery, and from that moment the canyon's life force ebbed quickly. A huge reservoir, absolutely not needed in this century, almost certainly not needed in the next, and conceivably never to be needed at all, began to fill." 
  Construction continued and on September 13, 1963, the dam was topped out. Work on the power plant and spillways began directly after the dam wall was complete. The spillway tunnels were excavated around both abutments of the dam, dropping steeply from their control gates on Lake Powell to merge with the lower ends of the diversion tunnels. This measure saved cost, but introduced a weak point where the two tunnels intersected. The upper ends of the diversion tunnels were then sealed with solid concrete. The first electricity was generated on September 4, 1964, with the power sent into the regional electric grid through a pair of long-distance transmission lines as far as Phoenix, Arizona and Farmington, New Mexico. It took two more years to complete all remaining aspects of the project. On September 22, 1966 Lady Bird Johnson gave the official dedication speech for Glen Canyon Dam, before a crowd of 3,000 people.
caption: Glen Canyon Dam under construction, 1962
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