I'm William Brangham and this is Horizons.

About one in ten Americans get their water from the Colorado River,

but a worsening drought driven in part by climate change is drying up that river.

States are now fighting over water rights.

What does that mean for the communities and industries who depend on that water for their survival?

And what is being done to help grant some urgently needed relief? communities and industries who depend on that water for their survival.

And what is being done to help grant some urgently needed relief?

Coming up next. Welcome to Horizons. The American West is running out of water. This is a crisis that has been

building for decades, driven by a long, persistent drought, but it will likely come to a head this summer.

Why? Thanks in part to climate change. This last winter was brutally warm.

And so that heavy snow that is supposed to fall on the mountain west didn't. Temperatures in

March hit record highs. That snowpack, that frozen high altitude bank of water in good years,

is supposed to slowly melt and send water down into rivers

and reservoirs to be used by millions. But that bank has barely any deposits left. Because of that,

the Colorado River is slipping to record low levels, threatening the water supply for 40 million

people across seven Western states.

This is also a power crisis. The two reservoirs on the Colorado, Lake Powell and Lake Mead,

generate hydroelectric power for millions. And those two colossal man-made lakes are also near

their record lows.

If water levels drop much further, those hydroelectric dams would stop working.

On top of all of this is a political stalemate.

Of these seven western states that draw water from the Colorado River Basin,

...