The National Park Service is moving to define and resolve a set of problems involved in protecting and restoring an overlooked and often abused resource: the soundscape.

One aspect of the noise pollution issue in parks, air tour overflights, has been a focus of the National Park Service since 1975. However, the deterioration of the soundscape due to all sources of human-caused noise is just starting to be addressed.

Sequoia and Kings Canyon National Parks are participating in a larger study that may point the way to the future of noise management in the national park system through the lessons learned and the techniques developed in those parks.

NPS Photo

Park scientists use special equipment to inventory sounds in a particular location.

For the past few years, these parks have been the subject of noise monitoring and analysis. A combination of unattended monitoring and targeted monitoring to establish daily and seasonal noise variations, and to identify the nature and levels of intrusive noise, is proving to be a promising strategy. The National Park Service is drafting a manual describing this method and plans to define a credible process for describing a park’s soundscape based on disparate data.

Additionally, a statistic called “L90,” the sound level exceeded 90% of the time, is a useful estimate of the natural soundscape, particularly under relatively noisy conditions. A policy is being drafted that spells out obligations of the National Park Service to inventory, monitor, and protect the soundscape.

Many concepts related to soundscape preservation are already discussed in the NPS education package “The Nature of Sound,” and a forthcoming NPS director’s order will provide further direction on this issue. Sequoia and Kings Canyon along with other parks will continue to developing noise management plans that detail what can and must be done to protect our soundscape resources.

Learn more about natural sounds
National Park Service Soundscapes web site.