Carlsbad Caverns National Park: Acoustic monitoring report, 2019
Olstad TA and Meyer E . 2024. Carlsbad Caverns National Park: Acoustic monitoring report, 2019. Science Report. NPS/SR—2024/168. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2305265
This study arose from Carlsbad Cavern National Park’s (CAVE) Technical Assistance Request (TAR; #9250), which identified the need for a baseline acoustic inventory to help understand the park’s existing wilderness character and evaluate potential acoustic impacts from military and civilian overflights. From late October to mid-December 2019, the Natural Sounds and Night Skies Division (NSNSD) gathered acoustic data at one site in CAVE to provide park managers with baseline information about the acoustic environment, including existing ambient sound levels and time-above noise level metrics in the park’s wilderness area. Overall, existing median ambient sound levels (LA50) at CAVE were remarkably quiet at 21.0 dB during the day and 20.1 dB at night. In the lower frequency range (20 – 1,250 Hz), the sound level of 35 dB (LAeq, 1s), indicative of quiet environments was exceeded only 3.18% of the day and 0.81% of the night. All other key sound levels (i.e., 45 dB and above) were exceeded less than 0.25% of the time. Due to an error with the acoustic recording device, metrics requiring off-site listening could not be determined. As a supplement, a geospatial sound model is used to predict existing and natural ambient sound levels of 32.3 (dBA) and 29.8 (dBA), respectively, with localized impacts from anthropogenic noise.
- Type
- Published Report
- Authors
- Olstad, Tyra; Meyer, Erik
- Date of Issue
- 2024-08
- Publisher
- National Park Service
- DOI
- 10.36967/2305265
- Units
- CAVE , NRSS , NSNSD
- Keywords
- Acoustic monitoring, baseline ambient, natural sound, noise, sound level, soundscape