Quiet is a resource, and Colorado’s Great Sand Dunes National Park & Preserve has plenty of it. In fact, acoustic monitoring reveals that this remarkable park has one of the quietest soundscapes in the entire country.
People who visit Great Sand Dunes National Park & Preserve are usually surprised. They’re surprised that the park is so big (150,000 acres). They’re surprised that sand dunes could possibly get that high (up to 750 feet from base to crest). They’re surprised that a park with a name like Great Sand Dunes has alpine forests, high country lakes, and numerous other ecological, geological, and historical delights. And they’re surprised that a place could be so darn quiet.
How quiet? Until recently that was a very subjective matter about which there were legitimate differences of opinion. Now, however, science has added an element of precision.
Over the past several decades, the federal government has gotten serious about monitoring and managing sound, especially the unwelcome variety dubbed noise. This interest is certainly not confined to natural areas such as national parks, but some of the most interesting data have been obtained there.
The Park Service’s Natural Resource Program Center (NRPC) has collected acoustical data in nearly 50 national park units over the past six years. This information gives scientists a basis for determining the natural ambient sound level (the sound levels existing in the absence of human-caused noise) for each park.
Gathering this information did more than just provide baseline information needed for effective monitoring. It provided information of immediate value to managers. Pursuant to NPS Management Policies, sound level is a resource to be appropriately managed.
Some parks are almost astonishingly quiet. Inside the crater at Haleakala National Park, for example, the natural ambient sound level was so low it didn’t register on the acoustical monitoring equipment that was used.
At the request of Great Sand Dunes, the NRPC’s natural sounds program staff deployed an acoustic monitoring system in the northwest corner of the park for several weeks (September 24 to October 10), obtained continuous sound pressure levels, and calculated natural ambient sound levels.
The data made a big impression on the researchers and the park staff. It turns out that Great Sand Dunes is one of the quietest locations ever monitored by the natural sounds program. It’s so quiet, in fact, that it rivals the Haleakala crater. Future monitoring will have to employ a high-sensitivity microphone to more accurately measure the extremely low sound levels existing in the park.
The downside of all this is that Great Sand Dunes is highly vulnerable to sound pollution. Almost any sounds of human origin, even the barely audible sound of plane flying a considerable distance away, could be deemed intrusive.
If you’d like to learn more about Great Sand Dunes, see the park’s online visitor guide at this site.
Postscript: Today is the 8th anniversary of the parks redesignation to National Park. Originally established as Great Sand Dunes National Monument in 1932, it became Great Sand Dunes National Park & Preserve through legislation signed into law by President Bill Clinton on November 22, 2000.