The spillway bridge at Hoover Dam.

Arizona spillway and bridge, Boulder Dam, 1931-1936

Glen Canyon Dam is a concrete arch dam on the Colorado River in northern Arizona in the United States, near the town of Page. Its reservoir is called Lake Powell, and is the second-largest artificial lake in the country, extending upriver well into Utah. The dam is named for Glen Canyon, a colorful series of gorges, most of which now lies under the reservoir. The dam was proposed in the 1950s as part of the Colorado River Storage Project, a U.S. Bureau of Reclamation (USBR) federal water project that would develop reservoir storage on the upper Colorado River and several of its major tributaries. Construction of Glen Canyon Dam started in 1956 and was not finished until 1966. The Glen Canyon Bridge or Glen Canyon Dam Bridge is a steel arch bridge in Coconino County, Arizona, carrying U.S. Route 89 across the Colorado River. The bridge was originally built by the United States Bureau of Reclamation to facilitate transportation of materials for the Glen Canyon Dam, which lies adjacent to the bridge just 865 feet (264 m) upstream. Carrying two lanes, the bridge rises over 700 feet (210 m) above the river and was the highest arch bridge in the world at the time of its completion in 1959.