Noise Monitoring in National Parks

What comes to mind when you think of a soundscape?  National Parks in the United States exist to preserve natural, cultural, and historical treasures. Have you ever considered that sound is a part of that treasure? People visit parks and wild places for various reasons: some to escape the hustle and bustle of everyday life, some to experience wildlife, and some to learn about their history and heritage. In each case, the soundscape of the park is an important part of the visitor experience. As such, protecting, maintaining, and restoring natural acoustical environments is essential.

Within the National Park Service, the  Natural Sounds and Night Skies Division is charged with measuring and protecting the unique soundscape of each park. Watch this video to learn how the Park Service collects sound measurements in remote areas. Explore the many reasons why the cultural, historical, and natural soundscapes found in America’s National Parks are important resources that deserve our protection.

Efforts are underway in our National Parks to preserve the sights and sounds that make up our natural and cultural history. From measuring current baseline levels to studying the impact of construction inside the park and activities around park borders, the National Park Service takes sound seriously.

Why measure and record the acoustic environment in National Parks?

• Perform baseline monitoring for the development of responsible management plans
• Provide quantitative information to comply with guidelines for new equipment purchases and development projects
• Conduct visitor experience studies
• Carry out impact studies for proposed park developments or park-adjacent operations such as energy development
• Perform biological studies for wildlife management
• Preserve cultural and historical sounds for future generations

Common Noise In and Around Parks

• Park operations, concessions, and contracting
• Aircraft
• Transportation
• Park adjacent energy development

Visitor Impact Studies and Visitor Experience

• Research indicates that exposure to natural sounds reduces stress, improves mood, and enhances cognition
• Conversely, prolonged exposure to artificial noise can create stress and reduce well-being

Wildlife Depend on Sound for

• Predation
• Communication
• Avoiding predators
• Protecting their young
• Courting and mating rituals
• Locating appropriate habitat

These essential animal behaviors and more can be adversely affected by noisy environments. Long-term park noise studies provide baseline data and allow for the development of noise management plans that utilize quantifiable measurements.

Permanent, Portable, and Attended Noise Monitoring

Today, noise consultants and park employees are carrying out long-term noise studies using reliable and energy-efficient noise monitoring solutions from Larson Davis^[1]. Larson Davis offers a family of noise monitoring systems with various power, communication, and sound recording options that can be implemented to suit the needs of various types of park and wildlife noise studies.

Larson Davis’ long-term, permanent, portable, and handheld monitoring systems have options that are critical for use in all kinds of wilderness and park environments:

• Weather data acquisition
  • Including wind speed, wind direction, temperature, humidity, and rainfall
• GPS positioning to log noise location and aid in noise mapping
• Event detection to identify when an established noise threshold has been exceeded
• Sound recording to determine the source of noise events by listening to the stored files
• Automatic storage of data to USB flash drive
• Web publishing, email or SMS alerts, and remote communication
• Complete set of metrics
  • Including 1/1 and 1/3 octave filters to 6.3 Hz, frequency weightings, time weightings, Ln percentiles, and more
• Options to power the device with batteries recharged via solar panel
• Low noise options

Portable monitoring systems can be deployed rapidly and easily moved from one data acquisition site to another. They include weather-resistant enclosures and outdoor microphone options. Our handheld, Class 1 sound level meters can be used for on-site evaluation and logging of noise levels.

Want to learn more about the National Park Service?

Information on park units is available here, as well as specifics for planning your next trip.

[1]A small sample of technical papers written with data collected on Larson Davis equipment is cited below:

• https://sites.warnercnr.colostate.edu/soundandlightecologyteam/wp-content/uploads/sites/146/2020/11/theodoreroosevelt.pdf
• https://sites.warnercnr.colostate.edu/soundandlightecologyteam/wp-content/uploads/sites/146/2020/11/ebeyslanding.pdf
• http://www.georgewright.org/1124haas.pdf

The views and opinions expressed in this article are those of the author / Larson Davis and do not necessarily represent the official policy or position of the National Park Service.