Canyonlands National Park, Snapshot Acoustic Monitoring Report, River Management Plan Study, 2024 – 2026

Meyer, Erik; Howell, Armin

This report presents preliminary results from an acoustic monitoring effort conducted by the Southeast Utah Group in technical consultation with National Park Service Natural Sounds and Night Skies Division (NSNSD) at Canyonlands National Park (CANY), undertaken in response to a technical assistance request from the park. As part of an ongoing river management planning effort and review of Wild and Scenic River eligibility along the Colorado River and Green River corridors, CANY established acoustic monitoring stations to sample the river soundscape before and through the primary river recreation season. Each station was equipped with a Larson Davis 831 Type 1 sound level meter with low-noise microphone and a digital audio recorder to support subsequent off-site listening analysis. Because the park lacked the technical expertise and software required to process and analyze the resulting acoustic data, NSNSD provided technical assistance to calculate sound level metrics, characterize existing and natural ambient conditions, and identify and quantify noise sources (including aircraft, watercraft, vehicles, and human activity) through spectrogram-based listening analysis. This report summarizes acoustic monitoring results across four sites (CANY015, CANY016, CANY019, and CANY020) and four seasons sampled between 2024 and 2026, providing park managers with baseline information on the acoustical environment, dominant noise sources, and existing versus natural ambient sound levels to inform river management planning and Wild and Scenic River eligibility determinations. A final product will include a published technical report; this snapshot report provides preliminary analysis.