2015-05-29 Declaration of Rachal K Roberts With Supplemental Material

R. Roberts Declaration - 1 - U.S. Department of Justice 7600 Sand Point Way NE No. 2:13-cv-1232-TSZ Seattle, WA 98115

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District Judge Thomas S. Zilly

IN THE UNITED STATES DISTRICT COURT

FOR THE WESTERN DISTRICT OF WASHINGTON

AT SEATTLE

CITIZENS OF THE EBEYS RESERVE FOR A HEALTHY, SAFE & PEACEFUL ENVIRONMENT, Plaintiff, v. U.S. DEPARTMENT OF THE NAVY; ADMIRAL PHIL DAVIDSON, in his official capacity as the Commander, Fleet Forces Command; and CAPTAIN MIKE NORTIER, in his official capacity as Commanding Officer Naval Air Station Whidbey Island, Defendants,

No. 2:13-cv-1232-TSZ DECLARATION OF RACHEL K. ROBERTS

I, Rachel K. Roberts, declare as follows:

1. I am an attorney for Defendants in the above-captioned case and am competent to

testify. The information in this declaration is based on my personal knowledge.

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Case 2:13-cv-01232-TSZ Document 44 Filed 05/29/15 Page 1 of 5


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2. Attached as Exhibit A is a true and correct tabulation of the annual number of

Field Carrier Landing Practice (FCLP) operations flown at Outlying Field (OLF)

Coupeville every year from 1967 through 2014.

3. Attached as Exhibit B is a true and correct copy of excerpts from Wyle Report WR

04-26, Aircraft Noise Study for Naval Air Station Whidbey Island and Outlying Field Coupeville

Washington, Wyle Laboratories, Oct. 2004.

4. Attached as Exhibit C is a true and correct copy of excerpts from AICUZ Study

Update for Naval Air Station Whidbey Islands Ault Field and Outlying Field Coupeville,

Washington, The Onyx Group, March 2005.

5. Attached as Exhibit D is a true and correct copy of Finding of No Significant

Impact for the Replacement of EA-6B Aircraft with EA-18G Aircraft at Naval Air Station

Whidbey Island, Department of the Navy, July 19, 2005.

6. Attached as Exhibit E is a true and correct copy of a redacted version of an April

16, 2013 Department of the Navy Memorandum from the Director, Air Warfare, to the Director,

Energy and Environmental Readiness Division.

7. Attached as Exhibit F is a true and correct copy of Burden of Disease from

Environmental Noise, Quantification of Healthy Life Years Lost in Europe, World Health

Organization Regional Office for Europe, 2011.

8. Attached as Exhibit G is a true and correct copy of Environmental Noise, Sleep

and Health, Clinical Review, Alain Muzet, 11 Sleep Med. Rev. 135142 (2007).

9. Attached as Exhibit H is a true and correct copy of Night Noise Guidelines for

Europe, World Health Organization Europe, 2009.



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10. Attached as Exhibit I is a true and correct copy of a series of emails between

myself and Mr. Mann, counsel for COER, dated between February 26, 2014, and March 13,

2014.

11. Attached as Exhibit J is a true and correct copy of a print-out from the U.S. Naval

Observatory, Astronomical Applications Department, Sun and Moon Data for December 21,

2014, for Coupeville, Island County, Wash. Retrieved from

http://aa.usno.navy.mil/rstt/onedaytable on May 29, 2015.

12. Attached as Exhibit K is a true and correct copy of the Airport Environs Map

Island County, Island County Department of Planning and Community Development, April 9,

1992.

13. Attached as Exhibit L is a true and correct copy of the Island County- Population

Density map, Wash. Dept of Ecology, GIS Tech. Servs., September 7, 2012.

DATED May 29, 2015

JOHN C. CRUDEN Assistant Attorney General Environment and Natural Resources Division s/ Rachel K. Roberts RACHEL K. ROBERTS Trial Attorney, Admitted to the Maryland Bar United States Department of Justice Natural Resources Section 7600 Sand Point Way NE Seattle WA 98115 (206) 526-6881 (tel); (206) 526-6665 (fax) E-mail: [email protected] BRIAN C. KIPNIS Assistant United States Attorney United States Attorneys Office 700 Stewart Street, Suite 5220 Seattle, Washington 98101-1271 Phone: (206) 553-7970



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Fax: (206) 553-4067 [email protected] Attorneys for Federal Defendants



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CERTIFICATE OF SERVICE

I hereby certify that on May 29, 2015, I electronically filed the foregoing with the Clerk

of the Court using the CM/ECF system which will send notification of such filing to the

following:

David S. Mann

Dated May 29, 2015

s/ Rachel K. Roberts RACHEL K. ROBERTS Trial Attorney, Admitted to the Maryland Bar United States Department of Justice Natural Resources Section 7600 Sand Point Way NE Seattle WA 98115 (206) 526-6881 (tel); (206) 526-6665 (fax) E-mail: [email protected]


Exhibit A

Case 2:13-cv-01232-TSZ Document 44-1 Filed 05/29/15 Page 1 of 2

AnnualNumberofFCLPsatOLFCoupevilleYear NumberofFCLPs Year NumberofFCLPs1967 1,236 2007 3,9761968 27,130 2008 2,5481969 39,246 2009 5,2921970 37,218 2010 6,4761971 18,392 2011 9,3781972 13,572 2012 9,6681973 16,764 2013 6,9721974 21,180 2014 6,0721975 24,8441976 17,8101977 17,7481978 24,3781979 20,2821980 12,1901981 16,8481982 14,4721983 11,7821984 12,7261985 13,9241986 22,2321987 30,3501988 30,4421989 22,5961990 32,0801991 27,0881992 25,8441993 21,3241994 21,6281995 19,8541996 13,0661997 9,7361998 6,8081999 6,7522000 6,3782001 3,5682002 4,1002003 7,6842004 4,3142005 3,5292006 3,413

Source:Years19671991arefromArgentv.UnitedStates ,124F.3d1277,1279(Fed.Cir.1997);19762002areinAppendixA.4tothe2005EA;20032014arefrompersonalcommunicationwithNavyofficials

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U.S. Dept. of Justice 7600 Sand Point Way NE

Seattle, WA 98115Exhibit A to Roberts Declaration


Exhibit B


Prepared by:

Martin Schmidt-Bremer Jr.J. Micah Downing

Geral LongTimothy LeDoux

Vanessa Thompkins

WYLE LABORATORIES, INC.WYLE AVIATION SERVICES GROUP

2001 JEFFERSON DAVIS HIGHWAYSUITE 701

ARLINGTON, VA 22202TEL:: 703 415 4550FAX: 703 415 4556WWW.WYLELABS.COM

Prepared for:

The Onyx Group1199 N. Fairfax Street

Suite 600Alexandria, VA 22314

Wyle Report

W R 0 4- 26

Aircraft Noise Study forNaval Air Station

Whidbey Island andOutlying Landing Field

Coupeville, WashingtonJob No. 50832

October 2004

FINAL

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Exhibit B to Roberts Declaration


Seattle, WA 98115


A i r c r a f t N o i s e S t u d y f o r N a v a l A i r S t a t i o n W h i d b e y I s l a n d a n d O u t l y i n g L a n d i n g F i e l d C o u p e v i l l e , W a s h i n g t o n

F I N A L

1-1

November 2004 WR 04-26

1.0 Introduct ion

Throughout the United States and overseas, the Naval Facilities Engineering Command (NAVFACENGCOM) conducts aircraft noise surveys at various Naval and Marine Corps Air Stations and associated facilities. The noise exposure contours developed during these studies are integrated primarily into Air Installation Compatible Use Zones (AICUZ) studies or other environmental documents, such as Environmental Impact Statements (EIS). These environmental documents are employed by NAVFACENGCOM to promote the compatibility of Navy and Marine Corps activities with neighboring land uses. This report presents the noise surveys results for Naval Air Station (NAS) Whidbey Islands Ault Field and Naval Outlying Landing Field (OLF) Coupeville.

The reports purpose is to present the Existing aircraft noise exposure for aircraft operations at NAS Whidbey Island for calendar year (CY) 03 and to present the Projected (CY13) aircraft noise exposure resulting from the transition of all EA-6B to EA-18G aircraft.

Section 1.1 summarizes the noise metrics discussed throughout this report, Section 1.2 explains the regulatory background pertaining to noise studies and Section 1.3 briefly describes the computer noise analysis model used to compute noise exposure. Section 2 provides a description of NAS Whidbey Island. Section 3 details flight and run-up operations, noise exposure, and AICUZ-related information for Existing conditions (CY03). Section 4 presents these same elements for the Projected (CY13) conditions, and Section 5 compares average annual day (AAD) Existing, Projected and Local Communitys Approved DNL contours. Appendix A provides a comprehensive discussion of how noise affects people and the environment. Appendix B contains depictions and technical data of the aircraft modeled. Appendix C contains an explanation of the abbreviations used.

1 . 1 N o i s e M e t r i c s

Noise represents one of the most prominent environmental issues associated with aircraft operations. Although many other sources of noise can be found in today's communities, aircraft noise is readily identifiable. An assessment of aircraft noise requires a general understanding of how sound is measured and how it affects people and the natural environment (See Appendix A).

The noise environment around a military or civil airfield normally is described in terms of the time-average sound level generated by the aircraft operating at that facility. These operations consist of the flight activities conducted during an average annual day. Operations at military airfields generally include fixed- and rotary-wing arrivals and departures, general vicinity flight patterns and pre-flight and maintenance aircraft engine "run-ups."

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The federal noise measure used for assessing aircraft noise exposures in communities near air installations is the Day-Night Average Sound Level (DNL, or Ldn ), described in terms of the decibel (dB). DNL is an average sound level generated by all aviation-related operations during an average 24-hour period. Acoustical daytime is defined as the period from 0700 to 2200 hours and acoustical nighttime is defined as the period from 2200 to 0700 hours the following morning. Nighttime sound levels of noise events are emphasized by adding a 10-dB weighting. The 10-dB weighting accounts for the generally lower background sound levels and greater community sensitivity to noise during these hours. As explained in Appendix A, DNL has been found to provide the best measure of long-term community reaction to transportation noises, especially aircraft noise.

DNL employs A-weighted sound levels. A-weighted denotes the adjustment of the frequency content of a noise event to represent the way in which the average human ear responds to that sound energy.

1 . 2 R e g u l a t o r y B a c k g r o u n d

This study was conducted under OPNAVInst 11010.36B for long range base planning under the Navy AICUZ program. The Federal Interagency Committee on Urban Noise (FICUN) was formed in 1979 and it published Guidelines for Considering Noise In Land-Use Planning and Control (FICUN, 1980). These guidelines complement federal agency criteria by providing for the consideration of noise in all land-use planning and interagency/intergovernmental processes. The FICUN established DNL as the most appropriate descriptor for all noise sources. In 1982, EPA published Guidelines for Noise Impact Analysis to provide all types of decision-makers with analytic procedures to uniformly express and quantify noise impacts (U. S. EPA, 1982). The American National Standards Institute (ANSI) endorsed DNL in 1990 as the acoustical measure to be used in assessing compatibility between various land uses and outdoor noise environment (ANSI, 1990). In 1992, the Federal Interagency Committee on Noise (FICON) reaffirmed the use of DNL (or Ldn) as the principal aircraft noise descriptor in the document entitled Federal Agency Review of Selected Airport Noise Analysis Issues (FICON, 1992).

1 . 3 C o m p u t e r i z e d N o i s e E x p o s u r e M o d e l

Aircraft noise exposure and compatible land-use analyses around Department of the Navy facilities generally use a computer program called NOISEMAP.

The latest NOISEMAP package of computer programs consists of BASEOPS Version 7.291, OMEGA10, OMEGA11, NOISEMAP Version 7.2, NMPLOT Version 4.87, and the latest issue of NOISEFILE. NOISEFILE is the Department of Defense aircraft noise database originating from the noise measurements of controlled flyovers at prescribed power, speed, and drag configurations for most military aircraft models. Runway coordinates, airfield information, flight

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tracks, flight profiles (power and speed settings and altitudes) along each track by each aircraft, numbers of flight operations, run-up coordinates, run-up profiles and run-up operations all can be entered into the BASEOPS software. The OMEGA10 program extrapolates and interpolates the Sound Exposure Levels (SELs) for flight operations for each aircraft model from the NOISEFILE database. It takes into consideration the specified speeds, engine thrust settings and environmental conditions appropriate to each type of flight operation. The OMEGA11 program calculates maximum A-weighted sound levels from ground run-up operations for each aircraft model. This program takes the engine thrust settings, and environmental conditions appropriate to run-up operations into consideration. The core NOISEMAP program incorporates the number of daytime and nighttime operations, flight paths, and aircraft profiles to calculate DNL values over a regular grid of points in area of interest. The NMPLOT program draws equal DNL contours for overlay onto land-use maps. For AICUZ studies, as a minimum, DNL contours of 65, 70, 75 and 80 dB are developed. NOISEMAP computer program results and noise impact guidelines provide a relative measure of noise effects around air facilities. NOISEMAP also has the flexibility of calculating sound levels at any specified point so that potential noise impacts at noise sensitive locations around an airfield can be identified (United States Air Force, 1992).

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3.0 Exist in g Aircraft Operat ions and Noise Exposure

3 . 1 F l i g h t O p e r a t i o n s

The number of flight operations (operations tempo) at NAS Whidbey Island has varied dramatically over the 28 years of available data (1976-2003). Several variable factors interact with each other differently to cause that variability. Some are relatively predictable factors (including, but not limited to, the number of squadrons/aircraft/pilots-crews, minimum training requirements, total annual flight hours available, etc.) and some are relatively unpredictable factors (including, but not limited to, the number of deployments for higher headquarters directed exercises, aircraft carrier deployment schedules, deployments directed by higher authority in response to world events, etc.). The average (mean) operations tempo at NAS Whidbey Island between 1976 and 2003 is 123,407 operations per year with a standard deviation of 30,783 (NASWI CP&LO Oct 2004).

For 2003 the annual operations used for noise modeling were 81,959 for Ault Field and 7,682 for Coupeville. Total operations figures for 2003 were reduced to account for general aviation operations of aircraft that only transit the air space (aircraft that do not take off or land at Ault Field) reported as total annual operations. According to NAS personnel, operations numbers in 2003 were even lower than in 2002 due to multiple deployments. Table 3-2 shows annual flight operations for the Existing conditions at NAS Whidbey Island and OLF Coupeville.

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Table 3-1. Modeled Flight Operations for NAS Whidbey Island and OLF Coupeville for CY 2003

0700-2200 2200-0700 TotalDeparture 3,935 241 4,176Interfacility - Whidbey Island to Coupeville 531 109 640

Total Departures 4,466 350 4,816Overhead-Break 1,860 136 1,996Interfacility - Coupeville to Whidbey Island 531 109 640TACAN 411 25 436IFR Full-Stop 1,643 101 1,744

Total Arrivals 4,445 371 4,816FCLP 18,983 3,967 22,950Touch and Go 9,160 433 9,593Depart and ReEnter 238 17 255GCA Box 2,032 1,832 3,864

Total Closed Pattern Operations 30,413 6,249 36,66239,324 6,970 46,294

LO-TACAN 4,289 81 4,370IFR 3,668 145 3,813

Total Departures 7,957 226 8,183VFR 4,290 81 4,371LO-TACAN 1,834 72 1,906IFR Full-Stop 1,834 72 1,906

Total Arrivals 7,958 225 8,183Touch and Go 12,867 244 13,111GCA Box 4,661 175 4,836

Total Closed Pattern Operations 17,528 419 17,94733,443 870 34,313

Departure Departure 211 114 325Arrival Straight-In Arrival 211 114 325

422 227 649Departure Departure 65 35 100

Arrival Straight-In Arrival 65 35 100129 70 199

Departure Departure 164 88 252Arrival Straight-In Arrival 164 88 252

328 176 50473,646 8,313 81,959

FCLP 6,390 1,292 7,682OLF COUPEVILLE TOTAL 6,390 1,292 7,682

80,036 9,605 89,641

1 Counted as 2 operations 2 Operation Numbers derived from 2004 ATAC Draft Report - Day/Night Split Percentage (65% / 35%) from WR 94-133 Transient aircraft modeled as P-3

Source: Brown, 12 August 2004

CVWP EA-6B

Departure

Arrival

Closed Pattern1

CVWP TOTAL

CPRW P-3

Departure

Arrival

Closed Pattern1

CPRW TOTAL

TRANSPORT C-9 2

Transport TOTAL

STATION C-12 2

Station TOTAL

TRANSIENT Transient 2, 3

Transient TOTAL

CVWP EA-6B Closed Pattern1

at OLF

Total Number of Modeled Operations for 2003 (all aircraft)

AULT FIELD TOTAL

CY03 OperationsTenant Name

Aircraft Type

Operation Type

Description

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3.2.4 Interfacility Tracks

Figure 3-9 illustrates the interfacility tracks from NAS Whidbey Island to OLF Coupeville and Figure 3-10 illustrates the interfacility tracks from OLF Coupeville to NAS Whidbey Island. Each of NAS Whidbey Islands runways has two tracks going to OLF Coupeville, one for each of OLF Coupevilles runways. Similarly, each of OLF Coupevilles runways has four tracks returning to NAS Whidbey Island, one for each of NAS Whidbey Islands runways. All interfacility tracks are routed to minimize overflight of residential areas.

3.2.5 Pattern Tracks at NAS Whidbey Island

There are 40 pattern tracks depicted for NAS Whidbey Island. Pattern tracks are divided into 4 Depart and Re-Enter, 24 Tower Pattern (Touch and Go/FCLP) and 12 GCA box tracks.

The Depart and Re-Enter tracks are located north and west of NAS Whidbey Island for noise mitigation purposes (Figures 3-11 and 3-12).

Pattern Tower (Touch and Go and FCLP) tracks are identical to each other and are thus not listed separately (Figures 3-13 and 3-14). As described in Section 3.2.3, Runways 07, 13 and 25 have three daytime and three nighttime tracks with abeam distances ranging from about 1 NM for tight daytime tracks to about 1.9 NM for wide nighttime tracks. Of the six tracks per runway, the wide daytime and tight nighttime tracks are identical. Just as with the overhead break arrival tracks, Runway 25 also has a peculiar center daytime track, referred to as the pork-chop track of the same description and for the same reason. Runway 31 is also different in that there are only four distinct tracks. The center daytime and tight nighttime tracks and the wide daytime and center nighttime tracks have identical abeam distances.

The GCA pattern tracks (Figures 3-15 and 3-16) are utilized from all four runways at NAS Whidbey Island.

3.2.6 FCLP Tracks at OLF Coupeville

Figures 3-17 through 3-18 illustrate the 12 FCLP tracks used at the OLF. Each track on Runway 14 is unique. Various distances, such as the abeam distance, increase starting with the tight daytime track and ending with the wide nighttime track. The difference in length between the downwind leg, and thus of the final leg of the wide daytime and tight nighttime tracks, is about 0.7 NM, which results in a noticeably larger, tight nighttime track.

The tracks on Runway 32, on the other hand, follow the distances outlined in Sections 3.2.3 and 3.2.5. There are three daytime and three nighttime tracks with abeam distances ranging from about 1 NM for tight daytime tracks to about 1.6 NM for wide nighttime tracks. Of the six tracks per runway, the wide daytime and tight nighttime tracks are identical.

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0

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90

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Calendar Month (2003)

Average Monthly Temperatures Average Monthly Humidity

3 . 3 F l i g h t P r o f i l e s a n d C l i m a t i c D a t a

Aircraft profile data for based and transient aircraft came from several sources. Aircraft flight profiles for the EA-6B were previously developed and approved by the US Navy for use in this study (Papapietro, 2004). P-3 profiles were obtained through interviews with based pilots (Wyle Laboratories Acoustics Group, 2004). Standard NOISEMAP profiles were used for the C-9 and C-12. All profiles for the EA-6B and EA-18G are documented in Wyle Report 04-08, Revised (Downing and Schmidt-Bremer Jr, 2004). Transient aircraft were modeled based on P-3 profiles.

Since weather is a factor in the propagation of noise, NOISEMAP requires the monthly average temperatures and relative humidity values to determine the appropriate values to represent the given year. The appropriate values for entry into NOISEMAP for CY03 for NAS Whidbey Island and OLF Coupeville are 50F (10C) and 79% Relative Humidity (RH), as calculated based on the data provided by the weather observer at Naval Pacific Meteorology and Oceanography Detachment Whidbey Island (Wyle Laboratories Acoustics Group, 2004). This data is presented in chart-format in Charts 3-1 and 3-2.

Chart 3-1. Temperature and Humidity Data for NAS Whidbey Island

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0

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20

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90

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Calendar Month (2003)

Average Monthly Temperatures Average Monthly Humidity

Chart 3-2. Temperature and Humidity Data for OLF Coupeville

3 . 4 P r e - F l i g h t a n d M a i n t e n a n c e R u n - U p O p e r a t i o n s

Pre-flight run-ups were modeled for the EA-6B aircraft with a power setting of approximately 95% RPM for a duration of one second prior to brake release.

In-frame and out-of-frame (test cell) maintenance run-up operations data for the EA-6B are documented in WR 04-08, Revised (Downing and Schmidt-Bremer Jr., 2004). The data for the P-3 were collected by phone and email communication with maintenance personnel from Patrol Reconnaissance Wing 10 (CPRW-10) (Dudley, 2004). Table 3-8 displays all modeled maintenance operations data.

3 . 5 N o i s e E x p o s u r e

Using the data described in Sections 3.1 through 3.4, NOISEMAP 7.2 with topography was used to calculate the 60 dB through 85 dB DNL contours for the AAD flight operations for CY03, and the results are shown in Figure 3-19.

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Aside from covering large areas of Island County, Figure 3-19 shows that the Existing (CY03) AAD 60 dB DNL contour extends northwest reaching San Juan County, north and east over Skagit County. The 65 dB contour remains over Island County for the most part, except for small parts of Skagit County where it reaches across Similk and Skagit Bays.

Table 3-9 shows the impacts of Existing aircraft operations at Ault Field and OLF Coupeville. Listed are population numbers, housing units and area in acres within the 60 to 85+ dB DNL contours at 5 dB increments. Ault Field and OLF Coupeville property and bodies of water are not included in the population and housing impact calculations. For Ault Field, the Existing 65 to less than 75 dB AAD DNL contour band contains 10,077 acres in off-station land area and an estimated population of 9,327 (Table 3-9). An estimated 52 people would be exposed to a DNL greater than 85 dB. An estimated 21 housing units are located within this contour band. For OLF Coupeville approximately 7,426 acres, 1,983 people and 1,011 housing units were impacted by the 65 to less than 75 dB DNL contour band. An estimated three people were exposed to a DNL greater than 85 dB.

The population data was obtained from the U.S. Census Bureau 2000 census. Census block-groups surrounding the NAS and the OLF were extracted from the most recent Topographically Integrated Geographic Encoding and Referencing (TIGER) files, while demographic data were extracted from the Summary Tape File 1A (STF1A). The total area outside the boundaries of both Ault Field and OLF Coupeville, and the number of residents and houses within each contour band, were then calculated for comparison purposes. Populations calculated with U.S. Census data are estimates and are most useful in determining relative change in population impact between different noise contours.

Table 3-8. Impacts of Existing CY03 Operations at NAS Whidbey Island and OLF Coupeville

Level (dB) Population Housing Units Area (acres)

60 dB to less than 65 dB 15720 7320 3122865 dB to less than 70 dB 5715 2560 608570 dB to less than 75 dB 3612 1477 399275 dB to less than 80 dB 2674 1120 535480 dB to less than 85 dB 289 145 92685 dB + 52 21 157


Notes: 2000 Census data utilized

Existing CY03 DNL Contours

Ault F

ield

OLF

Cou

pevi

lle

All counts exclude NAS Whidbey Island and OLF Coupeville boundaries and bodies of water

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4 . 1 P r e - f l i g h t a n d M a i n t e n a n c e R u n - u p O p e r a t i o n s

Preflight run-up operations are generally not accomplished for the based aircraft, thus none were modeled.

Table 4-3 presents the modeled maintenance run-up operations for the Projected conditions for the EA-18G and the P-3. All maintenance run-up operations for the P-3 remain unchanged from Existing conditions.

4 . 2 N o i s e E x p o s u r e

Using the data described above and in Section 3, NOISEMAP 7.2 with topography was used to calculate the 60 dB through 85 dB DNL contours for the AAD operations of the Projected condition, and the results are shown in Figure 4-1.

Projected condition DNL contours are smaller than Existing condition contours, such that the counties of San Juan and Snohomish County are no longer encompassed by the 60 dB DNL contour. The 60 dB DNL contour does, however, penetrate the western border of Skagit County and the 65 dB DNL contour extends into Skagit Bay. The 70 dB DNL and greater Projected condition contours resemble the 70+ dB and greater Existing condition DNL contours, and they cover large parts of Island County.

Table 4-4 shows the impacts of Projected aircraft operations from Ault Field and OLF Coupeville. Listed are population numbers, housing units and area in acres within the 60 to 85+ dB DNL contours at 5 dB increments. For Ault Field, the Projected 65 to less than 75 dB AAD DNL contour band contains 6,807 acres in off-station land area and an estimated population of 5,636 (Table 4-4). An estimated 2,369 housing units are located within this contour band. There are 27 people estimated to be exposed to an AAD DNL greater than 85 dB. For OLF Coupeville, approximately 7,432 acres, 1,785 people and 900 housing units are impacted by the 65 to less than 75 dB DNL contour band. There are no people estimated to be exposed to an AAD DNL greater than 85 dB. The computed contour areas exclude bodies of water and the areas of Ault Field and OLF Coupeville themselves.

The population data was obtained from the U.S. Census Bureau 2000 census; while updated data was requested from the local communities, it remains unavailable. Census block-groups surrounding Ault Field and OLF Coupeville were extracted from the most recent Topographically Integrated Geographic Encoding and Referencing (TIGER) files, while demographic data were extracted from the Summary Tape File 1A (STF1A). The total area outside the boundaries of Ault Field and OLF Coupeville, and the number of residents and housing units within each contour band, were then calculated for comparison purposes.

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Table 4-4. Impacts of Projected CY13 Operations at NAS Whidbey Island

Level (dB) Population Housing Units Area (acres)60 dB to less than 65 dB 3965 1659 444165 dB to less than 70 dB 2982 1271 272370 dB to less than 75 dB 2654 1098 408475 dB to less than 80 dB 2080 894 450580 dB to less than 85 dB 141 64 53985 dB + 27 11 120



Projected CY13 DNL Contours

OLF

Coup

evill

eA

ult F

ield

All counts exclude NAS Whidbey Island and OLF Coupeville boundaries and bodies of water

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5.0 Noise Exposure Contour Comparisons

In this section, contours for the local communitys Approved conditions are introduced, and then a comparison of three sets of contours is presented. First, a comparison is provided between the Existing and Projected condition contours. Then the local communitys Approved contours are compared against both Existing condition contours, as well as the Projected condition contours.

5 . 1 L o c a l C o m m u n i t y s A p p r o v e d C o n d i t i o n s C o n t o u r s

Figure 5-1 shows the local communitys Approved 60, 65, 70 and 75 dB DNL contours for Ault Field and OLF Coupeville. The data used to plot these contours was provided by the Onyx Group (Dorn, 2004).

Table 5-1 shows the impacts of the local communitys Approved noise contours around Ault Field and OLF Coupeville. Listed are population numbers, housing units and area in acres within the 60 to 75+ dB contours at 5 dB increments. For Ault Field, the 65 to less than 75 dB DNL contour band contains 7695 acres in off-station land area and an estimated population of 6,284. An estimated 2,629 housing units are located within this contour band. For OLF Coupeville, the 65 to less than 75 dB DNL contour band contains 8,964 acres in off-station land area and an estimated population of 2,801. Approximately 1,410 housing units are located within this contour band.

The population data was obtained from the U.S. Census Bureau 2000 census. Census block-groups surrounding the NAS and the OLF were extracted from the most recent Topographically Integrated Geographic Encoding and Referencing (TIGER) files, while demographic data were extracted from the Summary Tape File 1A (STF1A). The total area outside the boundaries of Ault Field and OLF Coupeville and the number of residents and housing units within each contour band were then calculated for comparison purposes.

5 . 2 C o m p a r i s o n o f E x i s t i n g v e r s u s P r o j e c t e d C o n d i t i o n s C o n t o u r s

Figure 5-2 shows a comparison of the Existing (CY03) and Projected (CY13) 65 through 75 dB DNL contours for Ault Field and OLF Coupeville. The figure shows clearly that the transition from the EA-6B to the EA-18G would result in a reduction in noise impact around both Ault Field and OLF Coupeville. This is further demonstrated in Tables 5-2 and 5-3 which show a reduction in area, people and housing units impacted by as much as 86 percent in one particular attribute, as a result of the replacement of the EA-6B with the EA-18G. This is primarily attributed to the better performance of the EA-18G, e.g., its climb-out rate is much faster that that of the EA-6B.

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Table 5-1. Impacts of Community's Approved Contours at NAS Whidbey Island

Level (dB) Population Housing Units Area (acres)60 dB to less than 65 dB 7682 3457 771565 dB to less than 70 dB 4782 1972 409370 dB to less than 75 dB 1502 657 360275 dB + 3195 1337 6693

60 dB to less than 65 dB 1931 906 354165 dB to less than 70 dB 1425 702 396370 dB to less than 75 dB 1376 708 500175 dB + 1201 601 2981


All counts exclude NAS Whidbey Island and OLF Coupeville boundaries and bo

Local Community's Approved DNL Contours

Ault F

ield

OLF

Coupevill

e

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Table 5-2. Impacts of Existing versus Projected Conditions Contours Around Ault Field

Table 5-3. Impacts of Existing versus Projected Conditions Contours Around OLF Coupeville

CY2003 CY2013

60 to less than 65 15,720 3,965 -75%

65 to less than 70 5,715 2,982 -48%

70 to less than 75 3,612 2,654 -27%

75 + 3,015 2,248 -25%

CY2003 CY2013

60 to less than 65 7,320 1,659 -77%

65 to less than 70 2,650 1,271 -52%

70 to less than 75 1,477 1,098 -26%

75 + 1,286 969 -25%

CY2003 CY2013

60 to less than 65 31,228 4,441 -86%

65 to less than 70 6,085 2,723 -55%

70 to less than 75 3,992 4,084 2%

75 + 6,437 5,164 -20%

Notes: Census Data: 2000All counts exclude bodies of waterNegative percentages show decreases

EXISTING VERSUS PROJECTED CONDITIONS CONTOURS AROUND AULT FIELD

DNL (dB)

DNL (dB)

Difference

Difference

Difference

DNL (dB)

Area (acres)

Population

Housing Units

CY2003 CY201360 to less than 65 1,372 480 -65%65 to less than 70 1,211 1,196 -1%70 to less than 75 772 589 -24%

75 + 407 228 -44%

CY2003 CY201360 to less than 65 686 273 -60%65 to less than 70 626 609 -3%70 to less than 75 385 291 -24%

75 + 195 108 -45%

CY2003 CY201360 to less than 65 2,441 1,545 -37%65 to less than 70 4,731 4,742 0%70 to less than 75 2,695 2,690 0%

75 + 1,297 536 -59%

Notes: Census Data: 2000All counts exclude bodies of waterNegative percentages show decreases

EXISTING VERSUS PROJECTED CONDITIONS CONTOURS AROUND OLF COUPEVILLE

DNL (dB)Population

Difference

DNL (dB)Housing Units

Difference

DNL (dB)Area (acres)

Difference

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5 . 3 C o m p a r i s o n o f E x i s t i n g v e r s u s L o c a l C o m m u n i t y s A p p r o v e d C o n d i t i o n s C o n t o u r s

Figure 5-3 shows a comparison of the Existing (CY03) and local communitys Approved noise contours for Ault Field and OLF Coupeville. This comparison shows that the area impacted under the local communitys Approved contours around Ault Field is actually smaller (for the most part) than the one under Existing conditions. This does not hold true for OLF Coupeville, however, where the local communitys Approved contours are larger than the Existing condition contours. The reasons for the difference are unknown; however, noise propagation due to the effects of topography and transmission of noise over water was probably not considered during the modeling of the local communitys Approved condition contours as the technology did not exist until recently.

5 . 4 C o m p a r i s o n o f P r o j e c t e d v e r s u s L o c a l C o m m u n i t y s A p p r o v e d C o n d i t i o n s C o n t o u r s

Noise contours under the local communitys Approved conditions and under the Navys Projected (CY13) conditions for Ault Field and OLF Coupeville are shown in Figure 5-4. The noise impact in CY13 would be smaller, with the exception of the 65 dB DNL contour east of Ault Field which protrudes slightly into Skagit County. The larger contours north and south of Ault Field are over water and would thus not impact any population. The impact around the OLF would largely decrease.

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References

American National Standards Institute, Inc. (ANSI). 1990. Sound Level Descriptors for Determination of Compatible Land Use. ANSI S12.40-1990 and ASA 88-1990.

ATAC Corporation. 2004. Draft Airfield and Airspace Baseline Development Study, 2 May 2004.

Brown, Cdr, Lt, 12 August 2004. Air Traffic Control, NAS Whidbey Island. Phone and email communication with Martin Schmidt-Bremer Jr.

Committee on Hearing, Bioacoustics and Biomechanics (CHABA). 1977. Guidelines for Preparing Environmental Impact Statements on Noise. The National Research Council, National Academy of Sciences.

Dorn, Greg, 22 July 2004. The Onyx Group GIS/Planner. Email correspondence with Martin Schmidt-Bremer Jr.

Downing, Micah, and Schmidt-Bremer Jr, M. 2004. Operational Noise Comparison Between EA-6B and EA-18G at NAS Whidbey Island and OLF Coupeville. Wyle Report 04-08 Revised, May 2004.

Dudley, Eric, ADC, 10 July 2004. Aircraft Maintenance, Patrol Reconnaissance Wing. NAS Whidbey Island. Phone and email correspondence with Martin Schmidt-Bremer Jr.

Federal Interagency Committee on Noise (FICON). 1992. Federal Agency Review of Selected Airport Noise Analysis Issues, August.

Federal Interagency Committee on Urban Noise (FICUN). 1980. Guidelines for Considering Noise in Land-Use Planning and Control, August.

Melaas, Richard, August 2004. CP&L Officer, NAS Whidbey Island. Personal and email correspondence with Martin Schmidt-Bremer Jr.

Noise Control Act of 1972. 1972. Retrieved 16 July 2002, from http://hydra.gsa.gov/pbs/pt/ call-in/nca.htm.

Papapietro, Antony F., CAPT, USN, 24 August 2004. CNAF Requirements Officer. Email correspondence with Martin Schmidt-Bremer Jr.

United States Air Force. 1992. Air Force Procedure for Predicting Noise Around Airbases: Noise Exposure Model (NOISEMAP) Technical Report. Report AL-TR-1992-0059.

U.S. Environmental Protection Agency (EPA). 1982. Guidelines for Noise Impact Analysis. Report 550/9-82-105 and #PB82-219205, April 1982.

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U.S. Environmental Protection Agency (EPA). 1972. Information on Levels of Environmental Noise Requisite to Protect the Public Health and Welfare With an Adequate Margin of Safety. Report 550/9-74-004. March 1982.

Wyle Laboratories Acoustics Group, 2004. Site Visit to Naval Air Station Whidbey Island, 15 to 19 March 2004 by Martin Schmidt-Bremer Jr and Micah Downing.

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APPENDIX A

DISCUSSION OF NOISE AND ITS EFFECT ON THE ENVIRONMENT

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Appendix A Discussion of Noise and Its Effect on The Environment

A.1 Basics of Sound

Noise is unwanted sound. Sound is all around us; sound becomes noise when it interferes with normal activities, such as sleep or conversation.

Sound is a physical phenomenon consisting of minute vibrations that travel through a medium, such as air, and are sensed by the human ear. Whether that sound is interpreted as pleasant (e.g., music) or unpleasant (e.g., jackhammers) depends largely on the listeners current activity, past experience, and attitude toward the source of that sound.

The measurement and human perception of sound involves three basic physical characteristics: intensity, frequency, and duration. First, intensity is a measure of the acoustic energy of the sound vibrations and is expressed in terms of sound pressure. The greater the sound pressure, the more energy carried by the sound and the louder the perception of that sound. The second important physical characteristic of sound is frequency, which is the number of times per second the air vibrates or oscillates. Low-frequency sounds are characterized as rumbles or roars, while high-frequency sounds are typified by sirens or screeches. The third important characteristic of sound is duration or the length of time the sound can be detected.

The loudest sounds that can be detected comfortably by the human ear have intensities that are a trillion times higher than those of sounds that can barely be detected. Because of this vast range, using a linear scale to represent the intensity of sound becomes very unwieldy. As a result, a logarithmic unit known as the decibel (abbreviated dB) is used to represent the intensity of a sound. Such a representation is called a sound level. A sound level of 0 dB is approximately the threshold of human hearing and is barely audible under extremely quiet listening conditions. Normal speech has a sound level of approximately 60 dB; sound levels above 120 dB begin to be felt inside the human ear as discomfort. Sound levels between 130 to 140 dB are felt as pain (Berglund and Lindvall 1995).

Because of the logarithmic nature of the decibel unit, sound levels cannot be arithmetically added or subtracted and are somewhat cumbersome to handle mathematically. However, some simple rules are useful in dealing with sound levels. First, if a sounds intensity is doubled, the sound level increases by 3 dB, regardless of the initial sound level. For example:

60 dB + 60 dB = 63 dB, and

80 dB + 80 dB = 83 dB.

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Second, the total sound level produced by two sounds of different levels is usually only slightly more than the higher of the two. For example:

60.0 dB + 70.0 dB = 70.4 dB.

Because the addition of sound levels is different than that of ordinary numbers, such addition is often referred to as decibel addition or energy addition. The latter term arises from the fact that what we are really doing when we add decibel values is first converting each decibel value to its corresponding acoustic energy, then adding the energies using the normal rules of addition, and finally converting the total energy back to its decibel equivalent.

The minimum change in the sound level of individual events that an average human ear can detect is about 3 dB. On average, a person perceives a change in sound level of about 10 dB as a doubling (or halving) of the sounds loudness, and this relation holds true for loud and quiet sounds. A decrease in sound level of 10 dB actually represents a 90% decrease in sound intensity but only a 50% decrease in perceived loudness because of the nonlinear response of the human ear (similar to most human senses).

Sound frequency is measured in terms of cycles per second (cps), or hertz (Hz), which is the standard unit for cps. The normal human ear can detect sounds that range in frequency from about 20 Hz to about 15,000 Hz. All sounds in this wide range of frequencies, however, are not heard equally by the human ear, which is most sensitive to frequencies in the 1,000 to 4,000 Hz range. Weighting curves have been developed to correspond to the sensitivity and perception of different types of sound. A-weighting and C-weighting are the two most common weightings. A-weighting accounts for frequency dependence by adjusting the very high and very low frequencies (below approximately 500 Hz and above approximately 10,000 Hz) to approximate the human ears lower sensitivities to those frequencies. C-weighting is nearly flat throughout the range of audible frequencies, hardly de-emphasizing the low frequency sound while approximating the human ears sensitivity to higher intensity sounds. The two curves shown in Figure A-1 are also the most adequate to quantify environmental noises.

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Source: ANSI S1.4 -1983 Specification of Sound Level Meters

Figure A-1. Frequency Response Characteristics of A and C Weighting Networks

A-Weighted Sound Level

Sound levels that are measured using A-weighting, called A-weighted sound levels, are often denoted by the unit dBA or dB(A) rather than dB. When the use of A-weighting is understood, the adjective A-weighted is often omitted and the measurements are expressed as dB. In this report (as in most environmental impact documents), dB units refer to A-weighted sound levels.

Noise potentially becomes an issue when its intensity exceeds the ambient or background sound pressures. Ambient background noise in metropolitan, urbanized areas typically varies from 60 to 70 dB and can be as high as 80 dB or greater; quiet suburban neighborhoods experience ambient noise levels of approximately 45-50 dB (U.S. Environmental Protection Agency 1978).

Figure A-2 is a chart of A-weighted sound levels from typical sounds. Some noise sources (air conditioner, vacuum cleaner) are continuous sounds which levels are constant for some time. Some (automobile, heavy truck) are the maximum sound during a vehicle pass-by. Some (urban daytime, urban nighttime) are averages over extended periods. A variety of noise metrics have been developed to describe noise over different time periods, as discussed below.

Aircraft noise consists of two major types of sound events: aircraft takeoffs and landings, and engine maintenance operations. The former can be described as intermittent sounds and the latter as continuous. Noise levels from flight operations exceeding background noise typically occur beneath main approach and departure corridors, in local air traffic patterns around the

-45-40-35-30-25-20-15-10-505

31.5 63 125 250 500 1000 2000 4000 8000 16000

Frequency (Hz)

Rel

ativ

e Le

vel (

dB)

C-Weighted A-Weighted

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airfield, and in areas immediately adjacent to parking ramps and aircraft staging areas. As aircraft in flight gain altitude, their noise contribution drops to lower levels, often becoming indistinguishable from the background.

Figure A-2. Typical A-Weighted Sound Levels of Common Sounds

0

10

20

30

40

50

60

70

80

90

100

110

120

130

On platform by passing train

Source: Handbook of Environmental Acoustics, James P. Cowan, 1994

On sidewalk by passing bus

Maximum levels in audience at rock concerts

Air raid siren at 50 ft (threshold of pain)

Threshold of Hearing

On sidewalk by passing typical automobile

Busy office

Typical suburban area background

Library Bedroom at night

Isolated broadcast study

Leaves rustling

Quiet

Moderate

Very Loud

Uncomfortable

4 x as loud

32 x as loud

1/4 x as loud

1/16 x as loud

16 x as loud

Loudness Compared to 70 dB

Sound Level (dBA)

Common Sounds

Typical airliner (B737) 3 miles from take-off

(directly under flight path)

Just Audible

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C-weighted Sound Level

Sound levels measured using a C-weighting are most appropriately called C-weighted sound levels (and noted dBC). C-weighting is nearly flat throughout the audible frequency range, hardly de-emphasizing the low frequency. This weighting scale is generally used to describe impulsive sounds. Sounds that are characterized as impulsive generally contain low frequencies. Impulsive sounds may induce secondary effects, such as shaking of a structure, rattling of windows, inducing vibrations. These secondary effects can cause additional annoyance and complaints.

The following definitions in the American National Standard Institute (ANSI) Report S12.9, Part 4 provide general concepts helpful in understanding impulsive sounds (American National Standards Institute 1996).

Impulsive Sound: Sound characterized by brief excursions of sound pressure (acoustic impulses) that significantly exceeds the ambient environmental sound pressure. The duration of a single impulsive sound is usually less than one second (American National Standards Institute 1996).

Highly Impulsive Sound: Sound from one of the following enumerated categories of sound sources: small-arms gunfire, metal hammering, wood hammering, drop hammering, pile driving, drop forging, pneumatic hammering, pavement breaking, metal impacts during rail-yard shunting operation, and riveting.

High-energy Impulsive Sound: Sound from one of the following enumerated categories of sound sources: quarry and mining explosions, sonic booms, demolition and industrial processes that use high explosives, military ordnance (e.g., armor, artillery and mortar fire, and bombs), explosive ignition of rockets and missiles, explosive industrial circuit breakers, and any other explosive source where the equivalent mass of dynamite exceeds 25 grams.

A.2 Noise Metrics

As used in environmental noise analyses, a metric refers to the unit or quantity that quantitatively measures the effect of noise on the environment. To quantify these effects, the Department of Defense and the Federal Aviation Administration use three noise-measuring techniques, or metrics: first, a measure of the highest sound level occurring during an individual aircraft overflight (single event); second, a combination of the maximum level of that single event with its duration; and third, a description of the noise environment based on the cumulative flight and engine maintenance activity. Single noise events can be described with Sound Exposure Level or Maximum Sound Level. Another measure of instantaneous level is the Peak Sound Pressure Level. The cumulative energy noise metric used is the Day/Night Average Sound Level. Metrics related to DNL include the Onset-Rate Adjusted Day/Night Average Sound Level, and the Equivalent Sound Level. In the state of California, it is mandated that

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average noise be described in terms of Community Noise Equivalent Level (State of California 1990). CNEL represents the Day/Evening/Night average noise exposure, calculated over a 24-hour period. Metrics and their uses are described below.

Maximum Sound Level (Lmax)

The highest A-weighted integrated sound level measured during a single event in which the sound level changes value with time (e.g., an aircraft overflight) is called the maximum A-weighted sound level or maximum sound level.

During an aircraft overflight, the noise level starts at the ambient or background noise level, rises to the maximum level as the aircraft flies closest to the observer, and returns to the background level as the aircraft recedes into the distance. The maximum sound level indicates the maximum sound level occurring for a fraction of a second. For aircraft noise, the "fraction of a second" over which the maximum level is defined is generally 1/8 second, and is denoted as "fast" response (American National Standards Institute 1988). Slowly varying or steady sounds are generally measured over a period of one second, denoted "slow" response. The maximum sound level is important in judging the interference caused by a noise event with conversation, TV or radio listening, sleep, or other common activities. Although it provides some measure of the intrusiveness of the event, it does not completely describe the total event, because it does not include the period of time that the sound is heard.

Peak Sound Pressure Level (Lpk)

The peak sound pressure level, is the highest instantaneous level obtained by a sound level measurement device. The peak sound pressure level is typically measured using a 20 microseconds or faster sampling rate, and is typically based on unweighted or linear response of the meter.

Sound Exposure Level (SEL)

Sound exposure level is a composite metric that represents both the intensity of a sound and its duration. Individual time-varying noise events (e.g., aircraft overflights) have two main characteristics: a sound level that changes throughout the event and a period of time during which the event is heard. SEL provides a measure of the net impact of the entire acoustic event, but it does not directly represent the sound level heard at any given time. During an aircraft flyover, SEL would include both the maximum noise level and the lower noise levels produced during onset and recess periods of the overflight.

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SEL is a logarithmic measure of the total acoustic energy transmitted to the listener during the event. Mathematically, it represents the sound level of a constant sound that would, in one second, generate the same acoustic energy as the actual time-varying noise event. For sound from aircraft overflights, which typically lasts more than one second, the SEL is usually greater than the Lmax because an individual overflight takes seconds and the maximum sound level (Lmax) occurs instantaneously. SEL represents the best metric to compare noise levels from overflights.

Day-Night Average Sound Level (DNL) and Community Noise Equivalent Level (CNEL)

Day-Night Average Sound Level and Community Noise Equivalent Level are composite metrics that account for SEL of all noise events in a 24-hour period. In order to account for increased human sensitivity to noise at night, a 10 dB penalty is applied to nighttime events (10:00 p.m. to 7:00 a.m. time period). A variant of the DNL, the CNEL level includes a 5-decibel penalty on noise during the 7:00 p.m. to 10:00 p.m. time period, and a 10-decibel penalty on noise during the 10:00 p.m. to 7:00 a.m. time period.

The above-described metrics are average quantities, mathematically representing the continuous A-weighted or C-weighted sound level that would be present if all of the variations in sound level that occur over a 24-hour period were smoothed out so as to contain the same total sound energy. These composite metrics account for the maximum noise levels, the duration of the events (sorties or operations), and the number of events that occur over a 24-hour period. Like SEL, neither DNL nor CNEL represent the sound level heard at any particular time, but quantifies the total sound energy received. While it is normalized as an average, it represents all of the sound energy, and is therefore a cumulative measure.

The penalties added to both the DNL and CNEL metrics account for the added intrusiveness of sounds that occur during normal sleeping hours, both because of the increased sensitivity to noise during those hours and because ambient sound levels during nighttime are typically about 10 dB lower than during daytime hours.

The inclusion of daytime and nighttime periods in the computation of the DNL and CNEL reflects their basic 24-hour definition. It can, however, be applied over periods of multiple days. For application to civil airports, where operations are consistent from day to day, DNL and CNEL are usually applied as an annual average. For some military airbases, where operations are not necessarily consistent from day to day, a common practice is to compute a 24-hour DNL or CNEL based on an average busy day, so that the calculated noise is not diluted by periods of low activity.

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Although DNL and CNEL provide a single measure of overall noise impact, they do not provide specific information on the number of noise events or the individual sound levels that occur during the 24-hour day. For example, a daily average sound level of 65 dB could result from a very few noisy events or a large number of quieter events.

Daily average sound levels are typically used for the evaluation of community noise effects (i.e., long-term annoyance), and particularly aircraft noise effects. In general, scientific studies and social surveys have found a high correlation between the percentages of groups of people highly annoyed and the level of average noise exposure measured in DNL (U.S. Environmental Protection Agency 1978 and Schultz 1978). The correlation from Schultz's original 1978 study is shown in Figure A-3. It represents the results of a large number of social surveys relating community responses to various types of noises, measured in day-night average sound level.

Figure A-3. Community Surveys of Noise Annoyance

A more recent study has reaffirmed this relationship (Fidell, et al. 1991). Figure A-4 (Federal Interagency Committee On Noise 1992) shows an updated form of the curve fit (Finegold, et al. 1994) in comparison with the original. The updated fit, which does not differ substantially from the original, is the current preferred form. In general, correlation coefficients of 0.85 to 0.95 are found between the percentages of groups of people highly annoyed and the level of average

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noise exposure. The correlation coefficients for the annoyance of individuals are relatively low, however, on the order of 0.5 or less. This is not surprising, considering the varying personal factors that influence the manner in which individuals react to noise. However, for the evaluation of community noise impacts, the scientific community has endorsed the use of DNL (American National Standards Institute 1980; American National Standards Institute 1988; U.S. Environmental Protection Agency 1972; Federal Interagency Committee On Urban Noise 1980 and Federal Interagency Committee On Noise 1992).

The use of DNL (CNEL in California) has been criticized as not accurately representing community annoyance and land-use compatibility with aircraft noise. Much of that criticism stems from a lack of understanding of the basis for the measurement or calculation of DNL. One frequent criticism is based on the inherent feeling that people react more to single noise events and not as much to "meaningless" time-average sound levels.

Figure A-4. Response of Communities to Noise; Comparison of Original (Schultz, 1978) and Current (Finegold, et al. 1994) Curve Fits

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In fact, a time-average noise metric, such as DNL and CNEL, takes into account both the noise levels of all individual events that occur during a 24-hour period and the number of times those events occur. The logarithmic nature of the decibel unit causes the noise levels of the loudest events to control the 24-hour average.

As a simple example of this characteristic, consider a case in which only one aircraft overflight occurs during the daytime over a 24-hour period, creating a sound level of 100 dB for 30 seconds. During the remaining 23 hours, 59 minutes, and 30 seconds of the day, the ambient sound level is 50 dB. The day-night average sound level for this 24-hour period is 65.9 dB. Assume, as a second example, that 10 such 30-second overflights occur during daytime hours during the next 24-hour period, with the same ambient sound level of 50 dB during the remaining 23 hours and 55 minutes of the day. The day-night average sound level for this 24-hour period is 75.5 dB. Clearly, the averaging of noise over a 24-hour period does not ignore the louder single events and tends to emphasize both the sound levels and number of those events.

Equivalent Sound Level (Leq)

Another cumulative noise metric that is useful in describing noise is the equivalent sound level. Leq is calculated to determine the steady-state noise level over a specified time period. The Leq metric can provide a more accurate quantification of noise exposure for a specific period, particularly for daytime periods when the nighttime penalty under the DNL metric is inappropriate.

Just as SEL has proven to be a good measure of the noise impact of a single event, Leq has been established to be a good measure of the impact of a series of events during a given time period. Also, while Leq is defined as an average, it is effectively a sum over that time period and is, thus, a measure of the cumulative impact of noise. For example, the sum of all noise-generating events during the period of 7 a.m. to 4 p.m. could provide the relative impact of noise generating events for a school day.

Onset-Rate Adjusted Day-Night Average Sound Level (Ldnr)

Military aircraft flying on Military Training Routes (MTRs) and in Restricted Areas/Ranges generate a noise environment that is somewhat different from that associated with airfield operations. As opposed to patterned or continuous noise environments associated with airfields, overflights along MTRs are highly sporadic, ranging from 10 per hour to less than one per week. Individual military overflight events also differ from typical community noise events in that noise from a low-altitude, high-airspeed flyover can have a rather sudden onset, exhibiting a rate of increase in sound level (onset rate) of up to 150 dB per second.

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To represent these differences, the conventional DNL metric is adjusted to account for the surprise effect of the sudden onset of aircraft noise events on humans with an adjustment ranging up to 11 dB above the normal Sound Exposure Level (Stusnick, et al. 1992). Onset rates between 15 to 150 dB per second require an adjustment of 0 to 11 dB, while onset rates below 15 dB per second require no adjustment. The adjusted DNL is designated as the onset-rate adjusted day-night average sound level (Ldnr).

Because of the sporadic occurrences of aircraft overflights along MTRs and in Restricted Areas/Ranges, the number of daily operations is determined from the number of flying days in the calendar month with the highest number of operations in the affected airspace or MTR in order to avoid seasonal periods of low activity. This monthly average is denoted Ldnmr. In the state of California, a variant of the Ldnmr includes a penalty for evening operations (7 p.m. to 10 p.m) and is denoted CNELmr.

A.3 Noise Effects

A.3.1 Annoyance

The primary effect of aircraft noise on exposed communities is one of long-term annoyance. Noise annoyance is defined by the EPA as any negative subjective reaction on the part of an individual or group (U.S. Environmental Protection Agency 1972). As noted in the discussion of DNL above, community annoyance is best measured by that metric.

The results of attitudinal surveys, conducted to find percentages of people who express various degrees of annoyance when exposed to different levels of DNL, are very consistent. The most useful metric for assessing peoples responses to noise impacts is the percentage of the exposed population expected to be highly annoyed. A wide variety of responses have been used to determine intrusiveness of noise and disturbances of speech, sleep, television or radio listening, and outdoor living. The concept of percent highly annoyed has provided the most consistent response of a community to a particular noise environment. The response is remarkably complex, and when considered on an individual basis, widely varies for any given noise level (Federal Interagency Committee On Noise 1992).

A number of nonacoustic factors have been identified that may influence the annoyance response of an individual. Newman and Beattie (1985) divided these factors into emotional and physical variables:

Emotional Variables

Feelings about the necessity or preventability of the noise; Judgment of the importance and value of the activity that is producing the noise; Activity at the time an individual hears the noise; Attitude about the environment;

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General sensitivity to noise; Belief about the effect of noise on health; and Feeling of fear associated with the noise.

Physical Variables

Type of neighborhood; Time of day; Season; Predictability of noise; Control over the noise source; and Length of time an individual is exposed to a noise.

A.3.2 Speech Interference

Speech interference associated with aircraft noise is a primary cause of annoyance to individuals on the ground. The disruption of routine activities such as radio or television listening, telephone use, or family conversation gives rise to frustration and irritation. The quality of speech communication is also important in classrooms, offices, and industrial settings and can cause fatigue and vocal strain in those who attempt to communicate over the noise. Speech is an acoustic signal characterized by rapid fluctuations in sound level and frequency pattern. It is essential for optimum speech intelligibility to recognize these continually shifting sound patterns. Not only does noise diminish the ability to perceive the auditory signal, but it also reduces a listeners ability to follow the pattern of signal fluctuation. In general, interference with speech communication occurs when intrusive noise exceeds about 60 dB (Federal Interagency Committee On Noise 1992).

Indoor speech interference can be expressed as a percentage of sentence intelligibility among two people speaking in relaxed conversation approximately 3 feet apart in a typical living room or bedroom (U.S. Environmental Protection Agency 1972). The percentage of sentence intelligibility is a non-linear function of the (steady) indoor background A-weighted sound level. Such a curve-fit yields 100 percent sentence intelligibility for background levels below 57 dB and yields less than 10 percent intelligibility for background levels above 73 dB. The function is especially sensitive to changes in sound level between 65 dB and 75 dB. As an example of the sensitivity, a 1 dB increase in background sound level from 70 dB to 71 dB yields a 14 percent decrease in sentence intelligibility. The sensitivity of speech interference to noise at 65 dB and above is consistent with the criterion of DNL 65 dB generally taken from the Schultz curve. This is consistent with the observation that speech interference is the primary cause of annoyance.

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A.3.3 Sleep Interference

Sleep interference is another source of annoyance and potential health concern associated with aircraft noise. Because of the intermittent nature and content of aircraft noise, it is more disturbing than continuous noise of equal energy. Given that quality sleep is requisite for good health, repeated occurrences of sleep interference could have an effect on overall health.

Sleep interference may be measured in either of two ways. Arousal represents actual awakening from sleep, while a change in sleep stage represents a shift from one of four sleep stages to another stage of lighter sleep without actual awakening. In general, arousal requires a somewhat higher noise level than does a change in sleep stage.

Sleep is not a continuous, uniform condition but a complex series of states through which the brain progresses in a cyclical pattern. Arousal from sleep is a function of a number of factors that include age, sex, sleep stage, noise level, frequency of noise occurrences, noise quality, and pre-sleep activity. Because individuals differ in their physiology, behavior, habitation, and

2015-05-29 Declaration of Rachal K Roberts With Supplemental Material

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