In 2007, years into a record-breaking drought throughout the southwestern U.S., officials along the Colorado River finally came to an agreement on how they’d deal with future water shortages — and then quietly hoped that wet weather would return.

But it didn’t.

Those states are now back at the negotiating table to hammer out new deals to avoid a slow-moving crisis on the river system that supports 40 million people in seven Western states.

The extent of the problem can be seen in a place like Page, Ariz., on the southern edge of Lake Powell, the second-largest reservoir in the country.

Jennifer Pitt, who works on Colorado River policy for the National Audubon Society, is standing on an overlook peering down at the lake itself and the giant concrete dam holding it in place.

“Now you can tell that there’s a river here underneath this reservoir because it has somewhat of a linear shape,” Pitt says, tracing the red rock canyon with her finger.