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Keeping Things Quiet In The National Parks


It seems inevitable in summer. When we head out to the patio for dinner, to enjoy the evening air and quiet broken by chirping birds at the feeders, a neighbor seemingly sees it as a signal to cut his grass. The gutteral roar of his lawnmower carries well, and proves far more irritating than a mosquito's buzz in the ear.

During the day the mower's noise might have blended in with the rest of the background noise we create -- cars and trucks on the streets, weed-whackers, stereos, vacuum cleaners -- and not seemed obtrusive. But in the evening, a time many of us prize for relaxing and enjoying the day's end, a single mower can sound amplified.

Much the same can be said of noise in national park settings. In places such as Yellowstone, Glacier, Shenandoah, Great Smoky Mountains, Acadia, and Canyonlands, just to cite a few examples, we often expect the sounds of silence, or at least those of nature. But as I found out last year during a visit to Congaree National Park in South Carolina, society's background noises can intrude on these natural settings.

Now we're learning that there are at times unintended consequences of good deeds in national parks. For instance, efforts to reduce traffic by using shuttle buses can actually create a noisier environment, according to studies at Rocky Mountain National Park and elsewhere in the park system.

A study recently released by the Acoustical Society of America pointed to the shuttle buses in Rocky Mountain as just one example of noise generators in the park system.

A study in Rocky Mountain National Park in Colorado, for example, revealed the aural consequences of reducing traffic congestion on park roads by adding shuttle buses to carry people to and from trailheads. The new shuttles succeeded in making trails accessible to a greater number of visitors. But each bus was also six times louder than a car; and the sounds of chatting hikers, backpack zippers, and gravel-crunching boots became concentrated at bus arrival times instead of being spread more evenly throughout the day. This good decision therefore had a negative effect on soundscape, shrinking the visitors’ “listening area,” or the distance around their heads at which they can still hear natural sounds.

To mute, so to speak, these sound generators, a Colorado State University researcher, Peter Newman, and colleagues are developing soundscape models that park staff can use to help predict how management actions -- such as bringing in a fleet of shuttle buses to reduce air pollution and traffic -- can affect the soundscape.

Such "soundscape maintenance," notes Professor Peterson (who worked for nearly two years as a ranger at Yosemite National Park), is beneficial not just to human visitors in the parks but to the resident wildlife as well.

“[Animals] want to know, ‘Where’s Bambi?’” Professor Newman explains in a release sent out by the Acoustical Society. “‘How far away do I have to be where [my young] can still hear me … or where I can hear that vole crawling beneath the surface of the leaves?’”

The studies Professor Newman's team conducted included surveys of park visitors to get their thoughts on noise levels in national parks. And they found that something as simple as signs denoting "quiet zones" were effective in getting visitors to keep the noise down.

Professor Newman is presenting the findings of his studies this week in Hong Kong at a joint meeting of the Acoustical Society of America, Acoustical Society of China, Western Pacific Acoustics Conference, and the Hong Kong Institute of Acoustics.

“This paper is about lessons learned,” says the professor. “Not only is noise important to people, but if we ask people to quiet down, they will.”

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The issue of is actually being addressed by the NPS.

Motorcycles Rev Up Noise Fears In National Parks

Karen Trevino heads the Natural Sounds and Night Skies Division for the National Park Service in Fort Collins, Colorado. Bike noise wasn't really on Trevino's radar until she had a personal experience. She and her son were walking outside the visitor center at Rocky Mountain National Park. Two motorcyclists were sitting on their bikes idling nearby.

KAREN TREVINO: And one of them winked at the other and thought it would be pretty funny. He throttled a couple of times pretty hard, which sent my son - I swear he must have jumped three feet sideways. And, you know, he was only three so, of course, he started crying and he was really upset. And I think it was probably about that point I realized, you know, maybe I should take some of these complaints from people more seriously.

Hardball, those poor souls probably need to keep their TV sets and satellite dishes powered up. Coolers for beer and soda pop take a lot of juice, too. How can any modern American family enjoy a park without their electronic and mechanical gadgets?

You must one of those nut cases who thinks national parks are for peaceful contemplation of nature or something like that. If so, then more power to ya.

Just got back from Great Smokey Mountain National Park - 3 day early! Every RV campground in the park allowed generators to run from 8am to 8pm - non stop. No way to escape inconsiderate idiots who are sitting outside at the table with doors and windows open while the generator runs. Park rangers respond like a deer in the headlights.

YPW- you are wrong. All highway motorcycles enterred into US commerce, including every HD model, and HD Police bikes, are all low-noise-emission regulated vehicles, producing about the same sound energy under full power at 50 ft, that a well running dishwasher makes from two rooms away. The levels of sound these products make are all remarkbly under the EPA requirements for maximum noise limits. The manufacturer's purposely build products to exceed the requirements by wide margins. Most standard motorcycles do not produce any audible exhaust note past 200ft while being prudently operated. The issue exist because of original noise controls, removed, replaced, alterred or rendered inoperable during efforts to customize or modify the running condition of the bike. In most states these acts are illegal. The standard motorcycles are legal.

I'm old school I guess. Camping is in a tent and I prefer not to be between a bog 'ol RV! It is harder and harder each year to find a place to pitch it. Canpgrounds are RV parks now and there is no place to stay. I wish our NPS and state park systems would leave a little bit more to Mother Nature!

The EPA doesn't produce, market, sell, locally control, certify or regulate motorcycle exhaust systems for direct sound energy. How a newly built highway motorcycle creates a specific soundscape into a an adjacent environment, by all of its outgoing sound sources, during a precise decibel meter measurement procedure is what the EPA's code of federal regulations controls. Not the exhaust mechanism. Besides, requiring operation with only "noise emissions control information labels" onboard an operating modified motorcycle, results in significantly raising the volume of a low-noise-emission regulated product that is purposely built to be far more silent then the regulations require. Noise Control laws that help owners to legally raise volumes are not known as effective enforcement methods to rid louder use. The label on an after-market exhaust, especially ones attached to a non-specific motorcycle, as warned by the EPA, can not be "markers" for police to use as an enforcement tool, because it is impossible for police to validate the EPA specifics of a vehicle. Only the obvious raised volumes entering law enforcement ears, easily detectible "hollow core" silencers, questionably visible by examination during roadstops, and other noise controls missing and determined to be rendered inoperable, can be effective tools, when a state or local jurisdiction institutionally assigns the burden of proof on a defendant to provide evidence their standard motorcycle's volume was not raised by the custom modifications. Legislate a by-law prohibiting raising volumes by modifications. Create a "Dare to Compare" affirmative defense, performed by sound engineers, or certified inspection station technicians to determine one variable, by measuring two exhaust on one standard motorcycle, at any same rpm, offered by Appendix A.3 of SAE's J1287-Enforcement of Excessive Motorcycle Noise Procedure. Let the traffic Judge be satisfied by the Dare, or order the fine to be paid. Soundscapes everywhere will then be missing excessive motorcycle noise.

I agree completely on the motorcycle issue. We've camped in Rocky Mountain NP Moraine Park Campground for several years. Our favorite site overlooks the huge Moraine Park itself, and also overlooks the busy road to the Cub and Fern Lake trailheads. We could sit out in the evenings and watch the many cars driving by, never hearing more than a whisper of noise. But when a Harley would drive down that road the noise was excessive, and lasted for a minute or more. It really drove home to me how loud these bikes are, and how far that sound carries. I can't for the life of me understand why this unnecessary noise is tolerated.

The soundscape program is not just a matter of impacts on other park visitors. The noise of human activities also has an impact on wildlife. Considering birds: an increase in noise exposes birds to increased predation by preventing them from hearing predators and from hearing alarm calls uttered by other birds, it drowns out the songs used by birds in the breeding season to establish territory and attract mates, and it drowns out the call notes used by birds for flock cohesion in migration and in winter habitat. Areas with too much noise may become unsuitable for some species because of these effects.

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