The boundless beauty of the Colorado River stretches far beyond what first appears surface deep.

It's a 1400 mile life-sustaining artery, pumping freshwater into the heart of the American West's ecology.

And for us humans, it serves as a critical hydropower highway.

Streaming power generated at Lake Powell, all the way to Lake Mead, the nation's largest reservoir,

where excess water is banked in a system that supplies 40 million people in seven states out West.

But that power is shrinking.

The Colorado River is about 20 percent smaller than it was just 20 years ago.

Singen Eberly studies the Colorado for the conservation organization American Rivers.

Three of the top 10 largest cities in the nation all get their water from the Colorado River.

So that's an amazing amount of impact on a system that's literally getting smaller.

Smaller and weaker, heavy demand from the Southwest's exploding population,

combined with rapid climate change in the heat of a decade's long mega drought,

have plummeted water levels at the two lakes that feed the river.

And just to give you a sense of the scope of this crisis, you go back before the drought and where I'm standing right now,

I'd be about 40 feet underwater.

Right now, both Lake Powell and Lake Mead are nearly three-fourths empty and projected to continue dropping.

So where exactly are we, Bob?

So right now, we're on top of the dam. Top of Glen Canyon Dam.

We look off to our left is Lake Powell and off to our right is the Colorado River.

We were given exclusive access to the Glen Canyon Dam, where water from the lake is released through eight massive turbines.

This is a goose that lays a golden egg with Southwest.

Generating enough power to electrify millions of homes, businesses, farms, and more than 50 Native American tribes.

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