North Cascades National Park Complex: Acoustic monitoring 2009-2011
Winnings CJ and Neel EG. 2013. North Cascades National Park Complex: Acoustic monitoring 2009-2011. Natural Resource Technical Report. NPS/NOCA/NRTR—2013/767. National Park Service. Fort Collins, Colorado
From 2009 through 2011, acoustic monitoring systems were deployed at 14 locations throughout North Cascades National Park Complex (NOCA). The purpose of this monitoring effort was to complete a baseline inventory of the acoustical environment of NOCA. The inventory was initiated in 2006 and in 2009 NOCA received funding to acquire equipment, employ one to two technicians, and analyze the data. This report summarizes the findings of the inventory efforts that took place from 2009 through 2011.The monitoring sites included a mix of backcountry and front country locations that varied in elevation and forest type. Systems were deployed for approximately 30 days at each location, where automatic monitoring was supplemented by on-site listening sessions. A variety of metrics were calculated at each site, including existing and natural ambient sound levels, percent time audible of extrinsic (human-caused) sounds, percent time above four key thresholds, hourly exceedence metrics, and dB levels for one-third octave bands. Results show that NOCA has concentrated areas of noise intrusions surrounded by large expanses with very low levels of human-caused sound. The most prevalent sources of human-caused sound include vehicles and aircraft. Although human-caused sounds occur infrequently in many areas, natural ambient sound levels are often relatively high due to the prevalence of cascading water. This finding is especially appropriate given that the term “Cascades” is NOCA’s namesake. Other prevalent natural sounds include birdsong and insects, and on occasion, animal vocalizations from species of management concern, such as grey wolves and spotted owls, have been recorded. These findings are important attributes for NOCA as a large wilderness park that can be used to monitor wilderness character. The baseline data collected during this period will help park managers determine if desired conditions for natural acoustical environments (often referred to as soundscapes) are being met in the future.
- Type
- Published Report
- Authors
- Winnings, Cathi; Neel, Evelyn
- Date of Issue
- 2013-06
- Publisher
- National Park Service
- Units
- LACH , NOCA , NRSS , NSNS , NSNSD , ROLA
- Keywords
- acoustical environment, Aircraft, amplitude, audibility, Backcountry, birdsong, Cascade, decibel, extrinsic sound, frontcountry, Human, intrinsic sound, Inventory, LACH, Lake Chelan National Recreation Area, Monitoring, NOCA, Noise, North Cascades National Park Complex, ROLA, Ross Lake National Recreation Area, Soundscape, Stephen Mather Wilderness, Vehicle, Water, Wilderness
- Subjects
- Ecological Framework: Landscapes | Soundscape | Soundscape