Walnut Canyon National Monument: Acoustic monitoring report

Job, Jacob

Between January 2011 and May 2013 an acoustical monitoring station (WACA003) was deployed in Walnut Canyon National Monument (WACA) by park staff. After repeated vandalism events, a new station (CHERRY001) was established nearby between September 2014 and December 2015. The goal of the study was to establish a baseline soundscape inventory of the acoustical soundscape within the park, specifically focusing on patterns of presence of gunshots, trains, and overflights. This inventory will be used to establish indicators and thresholds of soundscape quality that will support the park and NSNSD in developing a comprehensive approach to protecting the acoustical environment through soundscape management planning. Additionally, results of this study will help the park identify major sources of noise within the park, as well as provide a baseline understanding of the acoustical environment as a whole for use in potential future comparative studies. In each deployment, sound pressure level (SPL) was measured continuously every second by a calibrated, Type 1, Larson Davis 831 sound level meter. In this document, “sound pressure level” refers to broadband (12.5 Hz–20 kHz), A-weighted, 1-second time averaged sound level (LAeq, 1s), hereafter referred to as “sound level.” Sound levels are measured on a logarithmic scale relative to the reference sound pressure for atmospheric sources, 20 μPa. The logarithmic scale is a useful way to express the wide range of sound pressures perceived by the human ear. Sound levels are reported in decibels (dB). A-weighting is applied to sound levels in order to account for the response of the human ear (Harris, 1998). To approximate human hearing sensitivity, A-weighting discounts sounds below 1 kHz and above 6 kHz. Table 1 provides examples of sound levels measured in parks and common sound sources for general reference.

Walnut Canyon National Monument: Acoustic monitoring report

Series

Collections