Glen Canyon Dam, also known as the Crown Jewel of the Colorado River Storage Project, serves two purposes: electric power generation and water storage for the arid southwestern United States.
The storage is especially critical because the four states of the Upper Colorado River Basin are obligated by law to deliver at least 8.2 million acre feet of water a year to the three Lower Basin states.
The dam's eight 116,000 kilowatt turbines generate enough power to serve 650,000 people.
From its inception, the dam has generated controversy mainly because of its inundation of Glen Canyon (although 15 miles remain downstream).
Environmentalists dropped their opposition to its construction when the Bureau of Reclamation scrapped its plans for a second dam in Dinosaur National Monument in Utah.
Many, like the Sierra Club's David Brower, came to deeply regret that support. Wrote Brower, "Glen Canyon died, and I was partly responsible for its needless death."
Construction of the dam began in 1956, and it began to block the river's flow in 1963.
In the mid 1990s, Reclamation compiled an environmental impact statement on the effect of water releases from the dam on endangered species in the Colorado
River and also on beaches along the river's shore. The result was several days of high flows to simulate the impacts of the flash floods that used to rage down the river before the dam turned the waterway into a cool, even running steam.
The results were mixed but mainly disappointing. Even so, the experiment was replicated a decade later.
In late 2007, the seven Basin states tweaked their agreement on water releases, and more than 8.2 million acre feet of water is now being sent downstream to Lake Mead.
Carl Hayden Visitor Center is the dam's interpretive facility. Free 45 minute tours through the dam are offered, and photographs, artifacts, and video exhibits are featured. An endangered bonytail minnow swims in an aquarium, and a large three dimensional model of the region is the centerpiece.
