It’s the latest twist in the saga of Glen Canyon Dam, which has been at the center of recent concern about the shrinking Colorado River, even before news of the damaged pipes came to light. Water experts fear Lake Powell could drop so low that water would be unable to pass through hydropower turbines that generate electricity for about 5 million people across seven states. If it falls even lower, water would be unable to pass through the dam at all, keeping it out of the Grand Canyon just downstream of Lake Powell.