Hoover Dam created America’s largest reservoir.

Hoover Dam created America’s largest reservoir.

Formed by the damning of the Colorado River, Lake Mead, the nation’s largest reservoir, covers about 248 square miles and is capable of holding some 28.9 million acre-feet of water (an acre-foot is equivalent to about 325,000 gallons). The creation of Lake Mead (named for Elwood Mead, commissioner of the U.S. Bureau of Reclamation when the dam was being planned and built) flooded the community of St. Thomas, Nevada, and turned it into a ghost town. The last resident of the town, which was settled by Mormon pioneers in 1865, rowed away from his home in 1938. Today, the reservoir supplies water to farms, businesses and millions of people in Nevada, Arizona, California and Mexico. Lake Mead also is a popular site for boating, fishing and swimming; America’s first national recreation area was established there in 1964.Today, as a result of a drought the Colorado River basin has experienced for the past decade-and-a-half, Lake Mead has dropped to its lowest level since it was first filled in the 1930s.