Boulder City, Nev. At the only remaining boat launch ramp here on Lake Mead, the largest reservoir in the western US, officials recently put up a new sign: “Estimated wait time 4 hours.”
Amid the drought, scientists say, the region is now in its worst condition in more than 1,000 years, with Lake Mead 28% full. The lake has lost 169 feet from a surface elevation of 1,214 in 2000. For each foot to go under, about 20 feet of shoreline is exposed, according to National Park Service officials.