• In 1931, the construction of Hoover Dam began on the border of Arizona and Nevada, just 25 miles (40 km) east of Las Vegas. Named for President Hoover, the dam began impounding water from the Colorado River in 1935. The reservoir that resulted was called Lake Mead, named for Elwood Mead, the U.S. Bureau of Reclamation commissioner who oversaw the construction and died just before the dam was finished.
• In 1963, Glen Canyon Dam was completed upstream from Hoover Dam. The new reservoir was named Lake Powell after geologist John Wesley Powell, who surveyed this region. In 1893 Powell declared: “You gentlemen are piling up a heritage of conflict and litigation over water rights, for there is not enough water to supply the land.” He resigned from his job with the U.S. Geological Survey a year later.
• About 96% of the water in the Colorado River begins with snow melt in the Rocky Mountains, with the rest coming from precipitation, groundwater, and other watersheds. The river travels 1,440 miles (2,317 km) through Colorado and Utah, enters Lake Powell, goes through Glen Canyon Dam, then travels the length of the Grand Canyon before entering Lake Mead. After it exits Hoover Dam, it passes through Arizona and southern California before encountering the Morales Dam in Mexico, where what little water remains is diverted for agricultural use. The estuaries where the river used to enter the Gulf of California at Baha are now usually dry.
• Lake Mead is the largest reservoir in the U.S. by volume, and the second largest in surface area only to Lake Powell. It could contain the entire average annual flow of the Colorado River for two years.
• Lake Mead is 115 miles (185 km) long, up to 10 miles (16 km) wide, with 550 miles (885 km) of shoreline. It’s twice the size of Rhode Island. Lake Mead National Recreation Area, established in 1936, became the first national recreation area in the U.S.
• Lake Mead finally filled to its maximum possible capacity in 1983. At that point, the surface stood at 1,225 feet (373 m) above sea level. That was the first time that the spillways were activated.
• Today, 25 million people depend on the water from Lake Mead, while the turbines from Hoover Dam provide electricity for 40 million people including San Diego, Las Vegas, Phoenix, and Los Angeles. 90% of Las Vegas’ water comes from Lake Mead.
• Water from Lake Mead is used to irrigate around 5.5 million acres of cropland. California and Arizona provide about 25% of the food grown in the U.S.
• The problem is that Lake Mead has been shrinking steadily since 2000 due to increased demand and persistent drought. In 2013, Lake Mead became smaller than Lake Powell for the first time ever, though Lake Powell is also shrinking. Both reservoirs are currently at about 27% maximum capacity.
• Lake Mead fell to its lowest level ever in 2022 when it dropped to 1,041 feet (317 m). Hoover Dam can’t generate electricity if the level falls below 950 feet (289 m). When the pipeline leading to Las Vegas was about to go dry, a new pipeline was built at 860 feet (262 m). It went into operation in 2015, and the old pipeline now sits high and dry.
• Water provided by Lake Mead and Lake Powell allowed the southwestern U.S. to flourish. However, Lake Mead may be effectively dry by the year 2030.
