Preserving Silence in National Parks

A Battle Against Noise Aims to Save Our Natural Soundscapes

A group of boaters make their way down the peaceful Colorado River in the Grand Canyon. (Mark Lellouch, NPS)

The preservation of natural sounds in our national parks is a relatively new and still evolving project. The same can be said of our national parks. What Wallace Stegner called "the best idea we ever had"* did not spring full grown from the American mind. The painter George Catlin first proposed the park idea in 1832, but it was not until 1872 that Yellowstone became the first of our current 391 parks. Only much later did the public recognize the park's ecological value; the setting aside of Yellowstone had more to do with the preservation of visually stunning natural monuments than with any nascent environmentalism. Not until 1934, with the establishment of Everglades, was a national park instituted for the express purpose of protecting wildlife. And not until 1996 was Catlin's vision of a prairie park of "monotonous" landscape, with "desolate fields of silence (yet of beauty)," realized in Tall Grass Prairie National Preserve in Kansas.

As one more step in this gradual evolution, the Park Service established a Natural Sounds Program in 2000 with the aim of protecting and promoting the appreciation of park soundscapes. It would be a mistake to think of this aim as having originated "on high." In a 1998 study conducted by the University of Colorado, 76 percent of the Americans surveyed saw the opportunity to experience "natural peace and the sounds of nature" as a "very important" reason for preserving national parks.

But noise in parks, as in society at large, is on the rise—to the extent that peak-season decibel levels in the busiest areas of certain major parks rival those of New York City streets. Airplanes, cars, park maintenance machinery, campground generators, snowmobiles, and personal watercraft all contribute to the general commotion. The more room we make for our machines, the less room—and quiet—we leave for ourselves.

*Apparently Stegner was not the first to think so.  In 1912 James Bryce, the British ambassador to the United States, said that "the national park is the best idea American ever had."


Several times I heard park officials refer to the Natural Sounds office in Fort Collins, Colorado, as "Karen Trevino's shop," a good description of what I found when I stepped through the door. Cases of sound equipment—cables, decibel meters, microphones—were laid out like a dorm room's worth of gear on the hallway carpet, not far from several bicycles that staffers, most of them in their 20s, ride to work. A few members of the team were preparing for several days of intensive work out in the field. As animated as any of them was Karen Trevino.

"If the mayor of New York City is trying to make what people expect to be a noisy place quieter," she said, referring to the Bloomberg administration's 2007 revision of the city noise code, "what should we be doing in places that people expect to be quiet?" 

As a step toward answering that question, Trevino and her crew calibrate sound level information and convert it into color-coded visual representations that allow a day's worth of sound levels, and even an entire park's sound profile, to be seen at a glance. (Probably by the beginning of 2009 readers will be able to see some of these profiles at The technicians also make digital sound recordings to develop a "dictionary" by which these visual depictions can be interpreted. Much of their research is focused on creating plans to manage the roughly 185,000 air tours that fly over our parks each year—a major mandate of the National Parks Air Tour Management Act of 2000. The team is currently working on its first proposal, for Mount Rushmore, a 1200 acre unit with 5600 air tour overflights a year. Franklin Roosevelt once called this park "the shrine of democracy."

"When you think about it," Trevino says, "what's the highest tribute we pay in this country—really, in the world—of reverence and respect? A moment of silence. Now, that said, nature isn't silent. It can be very noisy. And people in parks aren't quiet all the time." Neither are things like cannon in a historical park like Gettysburg—nor should they be, according to Trevino. "Our job from a public policy standpoint is asking what noises are appropriate, and if they're appropriate, are they at acceptable levels?"

Trevino sees this as a learning process, not only for her young department but also for her. Some of what she's learned has passed to her private life. Recently she asked her babysitter to stop using the terms "indoor voice" and "outdoor voice" with her young children. "Sometimes it's perfectly appropriate to scream when you're indoors and to be very quiet when you're outdoors," she says.

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