SOUND ADDS A RICHNESS TO EXPERIENCING OUR NATIONAL PARKS that sight alone cannot provide: elk bugling in the cool autumn air of Great Sand Dunes National Park, waterfalls thundering in Yosemite Valley, the quiet hush of Haleakala Crater, muskets and artillery firing at Gettysburg National Military Park. The acoustic component or soundscape of any setting is the audio equivalent of a landscape, viewshed, or watershed and comprises all the sound conditions in a given environment, including human-caused and natural sounds. Acoustic resources that fall under NPS management include wildlife, waterfalls, wind, rain, and historical and cultural sounds.

Natural sounds are increasingly recognized as an important component of resource conditions and visitor opportunities in national parks because, as a growing body of research suggests, human-caused noise can be disruptive to natural ecological processes and visitor experiences. Noise impacts the acoustic environment much as smog affects the visual environment because it reduces the auditory horizon for both visitors and wildlife. In many cases, hearing is the only option for experiencing certain aspects of our environment, such as wildlife that can be heard at much greater distances than they can be seen. However, a healthy soundscape is not limited to the sounds of nature. Human sounds have an appropriate place in the outdoors. Cultural and historical sounds, such as the sounds of the working cattle ranch at Grant-Kohrs Ranch National Historic Site, and the church bell at Mission San Juan, San Antonio Missions National Historical Park, are important components of many national park units.

Despite their importance, soundscapes are often overlooked or impacts to this resource are understated in NPS planning and decision-making processes. For example, rationalizations include that the developed area already has noise impacts so adding more will not make much difference; this is an urban area so soundscapes are not an issue; or the area is so impacted there is no natural soundscape.

Another factor influencing management and policy decisions is that soundscape as a resource is a relatively new topic. As a result, there is a shorter history associated with policy and court decisions. In addition, many of the existing general acoustic research and policy decisions of other federal agencies, such as the Federal Aviation Administration (FAA), have been focused on urban areas and community annoyance, not on areas that are representative of national park units or on issues related to visitor experience. However, recent court decisions have implications for soundscape management. In September 2009, a federal judge issued a preliminary injunction against oil and gas well drilling at Baca National Wildlife Refuge (Colorado) that hinged in part on sound monitoring data collected by the Natural Sounds Program in adjacent Great Sand Dunes National Park (Streater 2009). The plaintiffs maintained that the soundscape at the refuge would be ruined by the noise from oil and gas wells. The judge cited that the refuge had a large expanse of undeveloped land with a significant “sense of place and quiet” (Gable 2009).

Establishing desired conditions and setting indicators and standards for soundscapes in planning documents give soundscape management additional political strength especially when external sources of noise threaten park soundscapes. The general management plan for Great Sand Dunes National Park includes desired conditions for soundscapes. This will be important as the previously mentioned lawsuit moves forward, since it confirms the level of protection for soundscapes that would need to be addressed by the U.S. Fish and Wildlife Service if oil and gas drilling in Baca National Wildlife Refuge is pursued. Another example is contained in FAA guidance (FAA 2007) on supplemental noise analyses for airport improvement projects. The guidance directs analysts to review approved park management plans to confirm how the park is managed for visitor use, resource conservation, and wildlife protection in order to identify sensitive locations in the vicinity of the project that may require further analysis.

The historical focus in the National Park Service has been on mechanized noise, especially aircraft overflights, or on park-specific noise issues such as snowmobiles, off-road vehicles, and personal watercraft, rather than on a comprehensive approach to soundscape management planning. Proper management of soundscapes is becoming more complex and challenging as threats to acoustic resources, both internal and external to park boundaries, increase. Planning is an essential step in addressing these threats. This article presents a brief overview of how soundscape management planning fits in the context of the NPS planning framework. It also identifies some of the research/issues that need to be addressed to assist in the development of management strategies and to ensure that park managers and policy makers have sufficient information to preserve, restore, and enhance soundscapes in accordance with NPS Management Policies 4.9.

Figure 1 and the supporting discussion illustrate the NPS planning framework and how soundscapes fit into this framework.

The historical focus in the National Park Service has been on mechanized noise, especially aircraft overflights, or on park-specific noise issues such as snowmobiles, off-road vehicles, and personal watercraft, rather than on a comprehensive approach to soundscape management planning.