Merced Wild and Scenic River Comprehensive Management Plan / DEIS

APPENDIX F 

ACOUSTICAL MEASUREMENT LOCATIONS 

Merced Wild and Scenic River Comprehensive Management Plan / DEIS F-1 

APPENDIX F 

ACOUSTICAL MEASUREMENT LOCATIONS 

This appendix includes Tables F-1 and F-2, which provide detailed descriptions of the acoustical 

measurement locations and corresponding levels and sources, and Figure F-1, which illustrates the 

acoustical measurement locations listed in the tables. 
APPENDIX F 

F-2 Merced Wild and Scenic River ComprehTABLE F-1: SUMMARY OF NOISE MEASUREMENTS

# Date Time Location 

Background 

Level (dBA) Description of Sound / 

1 9/11/99 8:30 First Merced River pedestrian bridge on John Muir 

Trail – base of Vernal Falls. 

64.0 River sounds predominated. Also, vis

contributed somewhat. Vernal Falls w

2 9/11/99 9:10 On the “mist” trail that winds up to Little Yosemite 

Valley adjacent to Vernal Falls. 

75.5 Waterfall noise predominated. Maxim

81 dBA were associated with people 

3 9/11/99 9:50 Viewing area atop Vernal Falls, overlooking the 

river and falls. 

65.5 The falls produced the background s

accounted for most of the measured sources accounted for the remainderto 70 dBA were associated with peop

4 9/11/99 10:47 Viewing area atop Nevada Falls overlooking river, 

trail bridge and falls. 

60.5 The falls produced the background s

accounted for most of the measured sources accounted for the remainder

5 9/11/99 12:00 Little Yosemite Valley campground area - 

approximately 700 feet east from river. 

40.0 Rushing water accounted for campgr

levels. Measurements were taken in a

6 9/11/99 3:00 Bunnell Cascade area (3 miles east of Little 

Yosemite Valley), on trail adjacent to river. 

53.5 Rushing water over granite cascades 

noise occurred during measurement. 

7 9/12/99 11:00 Soda Springs, about 2 miles east of Merced Lake at 

river side. 

56.0 Rushing water over granite cascades 

noise occurred during measurement. 

8 9/12/99 11:30 0.25 miles, off trail, away from river, north of Soda 

Springs area. 

41.5 Forest-related sounds predominated 

wind through trees). River sounds we

9 9/12/99 16:15 One-half mile south of Washburn Lake on trail 

about 300 feet to river. 

34.5 Background sound level reflected dis

nearby forest sources (birds, insects, 

10 9/12/99 16:30 On the shore at mid-portion of Washburn Lake. 30.5 No discernible sources of sound were 

measurement approximates the limit o

11 9/12/99 15:30 1 mile southeast of Washburn Lake within the 

overall Merced River confluence area. About 100 feet off river on trail. 

35.5 Sources included distant river rapids w

12 9/12/99 13:30 About 2 miles southeast of Washburn Lake near 

twin bridge at mouth of Merced Peak Fork River. About 200 feet from river. 

40.5 Canyon was narrow in this area, and 

amplified. Most sound was from rivewind in trees, birds, and high-altitude level from aircraft overflight was 43 d

13 9/12/99 14:30 On trail, climbing out of the Merced Peak Fork 

River valley, about 2.5 miles from Washburn. Gaining elevation away from river. 

38.5 Rushing water sounds were noticeab

elevation. Maximum noise level of 55aircraft overflight directly overhead, wnoticeable above the background lev
Acousti

Merced Wild and Scenic River Comprehensive Management Plan / DEIS TABLE F-1: SUMMARY OF NOISE MEASUREMENTS (CONTINUED)

# Date Time Location 

Background 

Level (dBA) Description of Sound / 

14 9/12/99 15:10 On trail almost to saddle on the divide between 

the Merced Peak Fork and Triple Peak Fork. 

35.0 Sources included distant rushing wat

and exposed bedrock seemed to amp

15 9/18/99 8:40 Yosemite Falls Trail, second footbridge north of 

Northside Drive. 

45.5 No water in Yosemite Falls Creek, pe

on Northside Drive (approximately 15measurement location). 

16 9/18/99 9:00 Yosemite Falls Trail, end of maintained foot trail 

(approximately 1,000 feet north of previous measurement). 

46.5 There was no water in Yosemite Falls 

trail were the predominant source of 65.5 dBA was associated with people past. 

17 9/18/99 9:30 Devil’s Elbow (on south side of Northside Drive 

adjacent to Merced River). 

44.0 River sounds were relatively low since 

rapids in this area. Very few people wlevel of 66.5 dBA associated with a b

18 9/18/99 9:50 El Capitan Meadow approximately 1,500 feet 

south of Northside Drive. 

38.5 The river was calm in this area, and n

Most of the sound came from wind topposite bank of the river. 

19 9/18/99 10:30 El Portal Road in the Gorge Segment of the 

Merced River. Along the river at the stone bridge between Arch Rock and Big Oak Flat Road. 

52.0 Rushing water sounds accounted for 

background level. Measurements wepeople. Some vehicle noise was audibut it was relatively minor due to distfeet away) and elevation (the river is below the grade of the roadway in th

20 9/18/99 11:15 Cascades Dam (approximately 500 feet east of 

dam along river area that is calm due to impoundment from the dam). 

48.5 The river was calm in this area, peop

some noise was attributable to their level of 62.5 dBA was due to a bus o

21 9/18/99 12:00 Swinging Bridge. 49.5 River was generally calm in this area. 

or wading or skipping stones were thnoise. 

22 9/18/99 12:30 Sentinel Bridge. 58.5 Substantial amount of visitor-related 

area. Vehicular traffic on bridge addewere generally slow (10-15 mph). Idlcontributed to background noise leve76.5 dBA was associated with tour b

23 9/18/99 14:40 Happy Isles. 59.0 Most of the noise was from people u

nearby. 
APPENDIX F 

F-4 Merced Wild and Scenic River ComprehTABLE F-1: SUMMARY OF NOISE MEASUREMENTS (CONTINUED)

# Date Time Location 

Background 

Level (dBA) Description of Sound / 

24 9/18/99 19:45 Midway between the river and main access road to 

the Upper Pines Campground. 

55.0 Noise was generally from the campg

talking (and yelling), generators from moving vehicles. 

25 9/19/99 6:00 Same location as #24. 32.0 No human-caused noise sources wer

this measurement was taken. 

26 9/19/99 10:30 In the middle of the old Wawona Bridge. 49.5 Most of the noise was associated wit

General Store across the roadway (i.eyelling, buses idling, vehicular traffic level of 58.5 dBA was associated witreplacement bridge. 

27 9/19/99 10:45 Along South Fork approximately 100 feet west of 

the covered bridge near the Pioneer History Center in Wawona. 

44.0 River sounds were noticeable with a 

cascades. Other sources of noise inclhistory center and horses and stagecbridge. 

NOTE: See Figure F-1 for a map showing the locations of the noise measurement sites. 
Acousti

Merced Wild and Scenic River Comprehensive Management Plan / DEIS TABLE F-2: SUMMARY OF NOISE MEASUREMENTS

Site # Year Location – Habitat Type 

Measured Media

Daytime

YOSE001 2005 White Wolf – Red fir forest 27YOSE002 2005 Tuolumne Meadows – Meadow/lake open area below treeline 34YOSE003 2005 Snow Flats – Subalpine/lodgepole 29YOSE004 2005 Granite Lakes – Alpine tundra 27YOSE005 2006 Lyell Winter Site – Meadow/lake open area below treeline 27

YOSE006* 2006 Yosemite Village – Developed concession area 51

YOSE007 2006 Hodgdon Meadow – Dense mixed conifer 28YOSE008 2006 Sentinel Rock – Upper vertical canyon 31YOSE009 2006 Ostrander Lake Trail – Dense lodgepole 28YOSE011 2006 Olmstead Point – Vertical canyon/open lodgepole 34

NOTE: See Figure F-1 for a map showing the locations of the noise measurement sites. * Site YOSE006 is the only 2005-2006 acoustical monitoring site within the Merced River Wild and Scenic River Corridor, and therefore is the only such site depicted oSOURCE: Yosemite National Park Acoustic Monitoring Report, 2005 & 2006. 
Yosemite Village 

 YOSE006

July 2012