(Natural News) The amount of water in the Lake Powell reservoir feeding into the Glen Canyon dam is falling to levels "lower than thought possible," to the point that the dam could stop producing energy altogether within a year.

Lake Powell, holding over 24 million acre-feet of water at full capacity, helps provide vital water supplies to a combined 40 million people living in the Southwestern United States. Lake Powell is also a major source of hydropower, and the water traveling through the Glen Canyon Dam powers eight generators that produce cheap and pollution-free energy for nearly six million homes and businesses across seven states.

But the water levels at Lake Powell are dwindling fast. It is currently at 28 percent of its full capacity. Back in March, water levels at the reservoir fell below 3,525 feet for the first time. This point is considered to be the critical buffer point to protect the dam's ability to generate hydropower. (Related: Ring the ALARM! Today's water crisis isn't a fire drill – It's apocalyptic.)

If the lake's water level drops by another 35 feet, the Glen Canyon Dam will no longer be able to generate power for the millions of people who rely on it.

"There are two elevations that we're concerned about right now," said Gene Shawcroft, general manager for the Central Utah Water Conservancy District and Colorado River Commissioner of Utah. "The first is 3,525 feet, the second is 3,490 feet." The latter, Shawcroft explained, is the point at which the turbines at the Glen Canyon Dam would be turned off.