Mead Plummets

Water levels in Lake Mead fell sharply again this summer and are nearing an elevation that would set off the first-ever official water shortage on the river. The reservoir, which supplies roughly 30 million users in the West, dropped to 1,087 feet above sea level, or about 40 percent of capacity. Were the lake to hit 1,075 feet, allocations on the river would be cut by more than 100 billion gallons under the terms of a 2007 agreement struck by seven Western states and Mexico.