Federally unprotected streams contribute most of the water to U.S. rivers
The first-of-its-kind analysis underscores the potential fallout of a Supreme Court ruling

Ephemeral streams like this one in Dixie National Forest in Utah flow only when it rains. The waterways, which are not federally protected under the Clean Water Act, contribute more than half of the water to U.S. rivers, new research finds.
Marc Solomon/Photodisc/Getty Images