Rain evaporates in the sky before reaching the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Glen Canyon Dam can be seen with low water levels of the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

Boats can be seen with low water levels of the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Navajo Generating Station, a coal-fired powerplant, can be seen near the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Glen Canyon Dam can be seen with low water levels of the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Colorado River flows from the Glen Canyon Dam on Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Glen Canyon Dam can be seen with low water levels of the Colorado River fed Lake Powell outside Page, Arizona, April, 14, 2015. (Photo by Jim Urquhart/Reuters)

The Grand Canyon National Park in northern Arizona, April, 12, 2015. (Photo by Jim Urquhart/Reuters)

Cattle gather near a water tank painted with the words “Water is Life” outside Grand Canyon National Park in northern Arizona, April 13, 2015. (Photo by Jim Urquhart/Reuters)

People take photos as the sun sets at the Grand Canyon National Park in northern Arizona, April 13, 2015. (Photo by Jim Urquhart/Reuters)

The Colorado River runs through Grand Canyon National Park in northern Arizona, April 13, 2015. (Photo by Jim Urquhart/Reuters)

A women sits on the south rim of Grand Canyon National Park in northern Arizona, April 12, 2015. (Photo by Jim Urquhart/Reuters)

Grand Canyon National Park in northern Arizona, April 14, 2015. (Photo by Jim Urquhart/Reuters)

Hikers make their way along a trail in Grand Canyon National Park in northern Arizona, April 12, 2015. (Photo by Jim Urquhart/Reuters)

The sun sets at Grand Canyon National Park in northern Arizona, April 14, 2015. (Photo by Jim Urquhart/Reuters)