Senior Vice President

The National Park Service has identified natural sounds as one of the park resources that needs to be preserved. The difficult question to answer is: how much natural sound or absence of non-natural / human produced sounds is appropriate for different park settings? Parks are established to preserve specific resources, and often natural sounds are one of the resources identified. Within a park, some areas will be more sensitive to the presence of human produced sounds than will others, depending on the specific setting and associated management objectives. Yet establishing limits for acceptable intrusions can also limit types of recreational or other activities, and hence, may be subject to challenge. Additionally, for parks requiring an Air Tour Management Plan, it will be necessary to define the conditions that define when “significant adverse impacts ” on the natural and cultural resources, visitor experiences, and tribal lands will occur.1 This paper describes basic concepts this author believes could aid in developing quantitative thresholds for inappropriate sounds in park settings, and outlines a process for determining those thresholds.