<P> Construction on Glen Canyon Dam began with a demolition blast keyed by the push of a button by President Dwight D. Eisenhower at his desk in the Oval Office on October 1, 1956 . The first blast started clearing tunnels for water diversion . On February 11, 1959, water was diverted through the tunnels so dam construction could begin . Later that year, the bridge was completed, allowing trucks to deliver equipment and materials for the dam, and also for the new town of Page, Arizona . </P> <P> Concrete placement started around the clock on June 17, 1960 . The last bucket of concrete was poured on September 13, 1963 . Over 5 million cubic yards (4,000,000 m3) of concrete make up Glen Canyon Dam . The Dam is 710 feet (216 m) high, with the surface elevation of the water at full pool being approximately 3700 feet (1100 m). Construction of the Dam cost $155 million, and 18 lives were lost in the process . From 1970 to 1980, turbines and generators were installed for hydroelectricity . On September 22, 1966, Glen Canyon Dam was dedicated by Lady Bird Johnson . </P> <P> Upon completion of Glen Canyon Dam on September 13, 1963, the Colorado River began to back up, no longer being diverted through the tunnels . The newly flooded Glen Canyon formed Lake Powell . It took 11 years for the lake to fill to the 3,700 feet (1,100 m) level, on June 22, 1980 . The lake level fluctuates considerably depending on the seasonal snow runoff from the Rocky Mountains . The all - time highest water level was reached on July 14, 1983, during one of the heaviest Colorado River floods in recorded history, in part influenced by a strong El Niño event . The lake rose to 3,708.34 feet (1,130.30 m) above sea level, with a water content of 25,757,086 acre feet (31.770898 km). </P> <P> Colorado River flows have been below average since the year 2000, leading to lower lake levels . In the winter of 2005 (before the spring run - off) the lake reached its lowest level since filling, an elevation of 3,555.10 feet (1,083.59 m) above sea level, which was approximately 150 feet (46 m) below full pool . Since 2005 the lake level has slowly rebounded, although it has not filled completely since then . Summer 2011 saw the third largest June and the second largest July runoff since the closure of Glen Canyon Dam, and the water level peaked at nearly 3,661 feet (1,116 m), 77 percent of capacity, on July 30 . However, the years 2012 and 2013 were, respectively, the third and fourth - lowest runoff years recorded on the Colorado River . By April 9, 2014 the lake level had fallen to 3,574.31 feet (1,089.45 m), largely erasing the gains made in 2011 . </P>

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