For 50 years, 55 miles of the Rio Grande through an 800-foot-tall gorge—from where it crosses the Colorado state line to near Rinconada—have been shielded from dams and diversions by the Wild and Scenic Rivers Act. What difference does it make for a river to be protected?

"In a way, you could say the biggest difference is that it has stayed the same," says Tim Palmer, author and photographer for Wild and Scenic Rivers: An American Legacy, which includes images of the Rio Grande.

The Rio Grande was among the first eight rivers defended when President Lyndon B Johnson signed the federal law on Oct. 2, 1968. The legislation was championed by then-Secretary of the Interior Stewart Udall, whose son Tom now serves as a New Mexico senator. Previous decades had seen rampant damming and diversions, and Montanans John and Frank Craighead championed the idea of protecting some rivers as free-flowing.

"It marked a dramatic turning point in our official regard for rivers," Palmer says. "We went from thinking that any dam, anywhere, at any cost was worthwhile, to recognizing that the very best of our natural rivers should remain intact."

Half a century later, the act's protections have been applied to 12,734 miles of 209 waterways—about one quarter of 1 percent of the nation's rivers. The nation's 80,000 dams, by comparison, affect at least 17 to 20 percent of American rivers.

"If you protect miles of the river under the Wild and Scenic Rivers Act, it prevents that; it makes it basically off-limits for those dams and diversions," says Jen Pelz, Rio Grande waterkeeper with WildEarth Guardians, in a film by American Rivers released for the anniversary. "It's a nice thing to have so you don't end up in a position where you're defending, because defending is kind of too late. It protects those crown jewels, those places you should never touch."

New Mexico boasts five such rivers—124 of 108,014 miles of rivers, or one-tenth of 1 percent. Palmer visited and photographed them all for his book. The Red River, four miles of which are protected before it joins the Rio Grande, was an exercise in contrasts between those four wild miles, and the stretch above it, which is overshadowed by an enormous molybdenum mine. The East Fork of the Jemez River was punctuated by waterfalls, and ponderosa pines wrapped the elegant curves of the Chama. On the Rio Grande, he hiked in two miles to the remote canyon of the Middle Box and rafted its signature whitewater. Six inches of snow fell on the Pecos River the day he went to see it, laying a white coat over red rock, green trees and blue water.

"It was just drop-dead beautiful," he recalls.

Without the act, many of these rivers wouldn't otherwise be as they were 50 years ago. The Chama was nearly dammed—again—before a remaining 25 miles of it were preserved as free-flowing. Palmer visited New Mexico again this month to speak at the Gila River Festival in Silver City, where locals are campaigning to see the Gila secure such designation in the face of a complex proposal to siphon off its water.

"The diversion is a classic boondoggle water resource project that should never be funded," says David Moryc with advocacy nonprofit American Rivers. "It just doesn't pencil out. It doesn't make economic sense. And there are real alternatives, shovel-ready projects right now that could be funded to improve conditions for ranchers and farmers without building this diversion project."

The act's protections can extend upstream, affecting activities like logging that can degrade water quality by increasing erosion or increase pollution and preserving fish habitat, points out Lisa Ronald, the Wild and Scenic Rivers 50th anniversary coordinator. In that position, she's leading a coalition of organizations planning events and running outreach around this milestone. These rivers not only benefit local ecology but can boost local recreation, to which the anglers and rafters who frequent the Rio Grande are a testament. While land protections have a variable spectrum, this is the only option for rivers, she says, and it's likely to become increasingly important in the decades ahead.

"There are a lot of articles being written about water and about the scarcity of water, and articles about how the Colorado River no longer reaches the ocean," she says. "As we move forward in time, water is going to become a much more heated issue than it is now, and the pressure to protect rivers is going to increase. So I think this 50th anniversary provides an opportunity not necessarily for the beginning of the thinking of river protection, but for a reawakening of river conservation going forward as we tackle some of these really contentious river-related issues of scarcity and pollution and unpredictable run-off events or unpredictable snowmelts and snowfalls."

American Rivers is running a four-year-long campaign to see 5,000 additional river miles designated—either through official congressional act or through local land management marking these areas as eligible or suitable for those protections. So far this year, one waterway in Montana has secured designation by Congress with legislation pending for five more states that would affect more than 1,500 river miles.

If clean water weren't enough of an argument, advocates point to the economic impact as well. The Outdoor Industry Association estimates recreation drives $887 billion in economic impact nationally, and as much as 75 percent of outdoor recreation takes place within half a mile of a stream or body of water.