In the summer of 1936, as Lake Mead filled behind the recently completed Hoover Dam, people living nearby worried that the rapidly accumulating body of water—at 400 feet deep and more than 100 miles long already the largest man-made reservoir in the country—was so massive and so incongruent with the dry Moapa Valley it was erasing that its presence would change the local weather and climate. In his book Colossus, Hoover Dam and the Making of the American Century (Free Press, 2010), Pulitzer Prize-winning journalist Michael Hiltzik writes that the conjecture was such that the federal government devised a test to address residents’ fears.
“Reclamation engineers anchored a timber raft on the surface with an evaporation pan, a flat tin saucer equipped with instruments that could measure changes in the surface to a thousandth of a foot, hoping to calculate how much water the giant reservoir might be evanescing into the atmosphere. The results told them that the lake’s level was falling by six-tenths of an inch per day, meaning that 25,000 gallons were evaporating every second.”
Their calculations indicated that Lake Mead loses 7 percent of its water annually to evaporation, which, government climatologist J. Cecil Alter reassured area residents, was not enough to change the local weather. “The water in a pitcher on a speaker’s stand is about as effective in air-conditioning an auditorium as Lake Mead is in modifying the climate,” Alter said, as quoted by Hiltzik.
Lake Mead may not have altered our weather, but it has changed our lives. Its water made sprawl possible throughout the arid Southwest, yet it also provides relief from that sprawl in the form of recreation in the desert. It is the cause of, and answer to, the way we live here today. Its shores are within a day’s drive for 30 million people. When temps hit triple digits, it can seem like they all converge on the lake at once.
Just how popular is Lake Mead on a summer weekend? Stats from Memorial Day tell the tale: 197,000 visitors in 58,064 vehicles between May 28 and 31, more than 48 percent of all national parks in the country get in a year; 1,052 warnings issued by rangers; 20 arrests, 19 of which were for misdemeanor offenses and one for a felony; six boat accidents, three involving injuries; 23 calls for emergency medical assistance, six of which required advanced life support.
Lake Mead gets 8 million visitors annually; at any given time, there are as many as 5,000 watercraft on the water. “Our visitation is equal to that of Yosemite and the Grand Canyon combined, and a lot of people don’t realize that,” says Andrew Muñoz, Lake Mead National Recreation Area’s public information officer.
They buy fuel, rent boats and slips, stock up on beer and food and pump about $500 million into the region’s economy. The park itself is akin to a small municipality, with an annual budget of $17.8 million and a staff of 220 to 300 people, depending on the season, doing jobs as varied as picking up trash, providing emergency medical services and maintaining computers.
Lake Mead is a resource, a city in miniature, an economic engine, a boating oasis and a recreational opportunity even if you never get your feet wet. The park dwarfs the lake, and it’s unique because three desert ecosystems converge there: the Sonoran, which runs southeast through Arizona and beyond; the Great Basin, which extends north through Nevada, Utah and Idaho; and the Mojave, which stretches west to California. Although it’s only been here for 75 years, it’s hard to imagine life without Lake Mead. Especially in the summer.