Weir Farm National Historical Park: Acoustic monitoring report, 2022–2023
Brown E. 2025. Weir Farm National Historical Park: Acoustic monitoring report, 2022–2023. Science Report. NPS/SR—2025/297. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2309695
In 2021, the Natural Sounds and Night Skies Division (NSNSD) received a technical assistance request (17694) to collect baseline acoustical data at Weir Farm National Historical Park (WEFA) to develop appropriate measures for desired soundscape conditions. From March to April 2022, two acoustical monitoring systems were deployed at two study sites in the park, WEFA001 (Pond Trail) on the east side of Nod Hill Road, just off the Pond Trail, and WEFA002 (Meadow), on the west side of Nod Hill Road, in the Burlingham complex, on the border of the Weir Preserve. Equipment was also deployed from October to November of 2023 at the same locations. Combined, these two seasons of acoustic measurements provide park managers with baseline information about the acoustic environment, including existing ambient sound levels, time-above noise level metrics in the park, and audibility of a variety of sound sources. Vehicles and aircraft were the most frequently heard noise sources at both sites during both spring and fall measurement periods. However, there were a variety of noise sources present in the acoustic environment and there were hours of the day when these two sources contributed less than 50% of noise audibility. Grounds care (both from WEFA and surrounding private parcels), and trains were the next most prevalent noise sources. The springtime measurement period captured a highly active amphibian chorus (including Wood Frog Rana sylvatica, and Spring Peeper Pseudacris crucifer). Overall, across all sites and seasons, existing median ambient sound levels (LA50) ranged from 38.2 dB – 40.9 dB during the daytime and 32.0 – 48.8 dB during the nighttime. When sound levels exceed 52 dBA, and if a speaker and audience are far apart, as they often are during interpretive programs (approx. 10 meters), speech interference begins to occur (EPA 1974). Over the two measurement periods, during the daytime, hourly LAeq sound levels exceeded this level less than 5.5% of the time.
- Type
- Published Report
- Authors
- Brown, Emma
- Date of Issue
- 2025-05
- Publisher
- National Park Service
- DOI
- 10.36967/2309695
- Units
- NRSS , NSNSD , WEFA
- Keywords
- Acoustic monitoring, baseline ambient, natural sound, noise, sound level, soundscape