Glacier National Park: Air tour noise modeling report

Beeco, J.; Lignell, Brent

The purpose of this study was to analyze noise from commercial air tours to inform a backcountry management plan under development at Glacier National Park. Due to the geographic extent of air tour routes over the park, aircraft noise can propagate into backcountry areas of the park. This report provides the most up-to-date information on air tour routes, quantitative noise modeling of the aircraft that use these routes, and a discussion on noise management strategies. Air tour routes commonly used by commercial operators were modeled, and a variety of acoustic metrics were generated to estimate noise effects and characterize conditions geospatially across the park. This study was conducted in four primary phases. First, the identification of air routes was needed to understand where, at what altitude, and what type of aircraft were conducting air tours over the park. This information was provided by air tour operators. The second and third phases included modeling operations and scenarios. Operations represent the suite of single aircraft/route/altitude combinations typically flown by air tour operators. By modeling each operation separately, an understanding could be gained about how each operation influenced the acoustic environment in the park. Additionally, the operations then become the foundation for building scenarios, which are one or more flights assigned to one or more operations. These scenarios were used to represent past, current, or plausible future acoustic conditions of from commercial air tour activity. The final phase was to estimate how noise would influence the backcountry visitor experience. This was completed by inputting results from the noise models into a regression that estimates the percent of visitors who might report that aircraft noise interfered with the ability to enjoy natural quiet.

Glacier National Park: Air tour noise modeling report

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