Colorado River

In this July 28, 2014, file photo, lightning strikes over Lake Mead near Hoover Dam that impounds Colorado River water at the Lake Mead National Recreation Area in Arizona. President Donald Trump on Tuesday, April 16, 2019, signed a plan to cut back on the use of water from the Colorado River, which serves 40 million people in the U.S. West. (AP Photo/John Locher,
File)