by The American Geosciences Institute Monday, February 1, 2016
This man-made lake, when full, is the largest such reservoir by volume in the United States. Over the last 15 years, however, drought has dropped the water level by 37 meters, to its lowest level since impoundment, leaving an infamous “bathtub ring” and exposing a previously submerged “ghost” town.
The dam that impounds the lake was the largest in the world when it was completed in 1936 and was originally named for the canyon in which it sits. The canyon was carved over the last 5 million years through colorful Paleozoic and Mesozoic strata that were uplifted during the Mesozoic and then faulted and tilted during the Paleogene.
The dam’s iconic facade has been photographed by Ansel Adams and featured in dozens of television shows and films, including the 1949 film-noir classic “The Lady Gambles” starring Barbara Stanwyck.
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Answer: Lake Mead, an impoundment of the Colorado River on the border of Nevada and Arizona, is the largest man-made reservoir by volume in the United States when full. However, over the last 15 years, the water level has dropped by about 37 meters. The lake is impounded by the Hoover Dam (formerly Boulder Dam), which was completed in 1936. Photo is by Sarah Rydgren.
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