HomeMy WebLinkAboutCT 02-07; EMERALD POINT ESTATES; ACOUSTICAL MONITORING SURVEY; 2001-04-27•
Investigative Science and Engineering, Inc.
3545 Camino Del Rio South, Suite E
San Diego, CA 92108-4003
April 27, 20q~
Ms., Kristine Zortman Greysto!1~ Homes, hic., ,
5780 Fleet Street, Suite 300
Carlsbad" CA 92008
Phone/Fax: 619-640-9379/619-640-0763
www.investigative-science.cbm
Subject: 'BCS FAR 150 Site Compliance Survey -Carlsbad, CA
(ISE Report #01-014)
Dear Ms. Zortman:
, At the request of Jack Henthorn & Associates, Investigative Science and
Engineering (ISE) has performed an acoustical monitoring survey of the proposedBCS
property located in the City of Carlsbad to ascertain the location of current community
noise (CNEL) contours due to flight operations from nearby McClellan Palomar Airport.
Specifically, this study was performed to verify the location of the 6'5 dBA CNEL
noise contour as it pertains to the current property development configuration and
compare these findings against the published noise exposure contours for the airport.
The results of our survey are presented in this letter report.
~ Introduction and Definitions
EXisting Site Characterization
The BCS development is located within the City of Carlsbad apprOXimately one
mile southwest from the McClellan Palomar Airport (refer to Figure 1 Oelow). Currently,
the site resides as fallow agriculture/undeveloped open space and i,s bordered to the
north by Palomar Airport Road, to the east and south by residential development, and to
the west by residential development. '
The primary concern is the location of ~he 65 dBA CNEL noise contour as
published in the Noise Element of the City of Carlsbad General Pla~ and in the' Federal
Air Regulations (FAR) Part 150 Noise Compatibility Program for McClellan PalorTiar
Airpor:t. The current site configuration and location of the published 65-dBA CNEL noise
contour is shown below in Figure 2.
[0) re ~ E nnrrm
lffiEMAY 2001 ~
GREYSTONE HOMES INC.
SAN DIEGO DMSION I --.... -:;.......--_ ... -.. _-_ .. _ ....
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 2 of 12
Figure 1: Project Vicinity Map (Thomas Guide Page 1127, Grid 83)
. paloma0!!:!!o!! Ro.!,~_. ---' -------I ! c:::-Flight Activity Zone
~ --!:-:::-~ -.--"-.. -"--.-.. -~ y ~
i " I \ I 65 CNEL Noise Contour -I I \ . . \ I __ ~ ___ ~-----------------
\ \ / ;
Figure 2: 8CS Property Site Development Configuration
Current Proposed
Development Conflguratlor , ..
"
W~·
'j ..,.;,j.'-.....J.. .• /= ......... '. , . / :r---..r---..... / " .,
.';" ',. / /' .. , ~"
; .
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad; CA
ISE Report #01-014
April 27, 2001
Page 3 of 12
Acoustical Definitions
Noise is generally defined as unwanted or ~nnoying sound that is .typically . " ..
associated with human activity and which interferes with or disrupts normal activities. . . .. '
A.lthough exposure t6 high noise levels has· be~n demohstra~ed to ~use h~aring 19~5, . . ,. ', ...... : '. ,
, the .'principal. human' response to enviro~mental noise is· annoyance. The: resPQnse' of . ..'..'.' ....
'individuals to similar noise events is diverse and influenced by the type of (loise,' 'the ':. > . ':,": .,'
perceived importance of the noise and its appropriateness in the setting, the Ume of day,' . ' .... , ..... :,.: '.;
and the sensitivity of the individual hearing the sound. . .,' ; .. .. ....,.. . .. ' ."
M '.: ":
Airborne sound is a rapid fluctuation of air: pressure 'above and ,below
atm'osph~ric ·Ievels. The loudest sound~ the human ear can'" hear comfortably are
approximatelY one trillion (a one with 12 zeros following it) times the acoustic energy that·
the ear can barely detect. Because of this vast range, any' attempt to repres~Dt th~
acoustic intensity of a particular sound on a linear scale becomes unwieldy. As a r~sult
of this, a logarithmic ratio known as the decibel (dB) is commonly employed. A sound
level of zero "0" dB is scaled such that it is defined as the threshold of hearing, which
would be barely audible to a human of normal hearing under extremely quiet listening
conditions and would correspond to a sound pressure level equal to the reference level.
Most of the sounds we hear in the environment do not consist of a si.ngle
frequency, but rather a broad band of frequencies differing in sound' level. The intensities
of each frequency add together to generate the sound we hear. The method commonly
used to quantify environmental sounds consists of determining all of the frequencies of a
sound according to a weighting system that reflects the nonlinear. response .
characteristics of the human ear. This is called "A" weighting, and the decibel level
measured is called the A-weighted sound level (or dBA). In practice, the level of a noise
source is conveniently measured using a sound level meter that inGludes a filter
corresponding to the dBA curve.
Although the A-weighted sound level may adequately indicate the level of
environmental noise at any instant in time, community noise levels vary continuously.
Most environmental noise includes a collection of sounds frOm distant sources that
create a relatively steady background noise in which no particular source is identifiable .
.For this type of noise a single descriptor called the Leq (or equivalent sound level) is
used. Leq is the energy-mean A-weighted sound level during a measured time interval.-,t
IS the 'equiyalent' constant sound level that would hav~ to be produced by a" given
source to equal the average of the fluctuating level measured. For. most a90ustical
studies, the monitoring interval is generally taken as one-hour and is abbreviated Leq-h.
In addition, it is often desir~ble to know the acoustic range of the noise sOurce being
measured. This is accomplished through the maximum and minimum measured sound
level (Lmax and Lmin) indicators. The Lmin val~e obtained for a particular monitoring
location is often called the acoustic floor for that location. The highest noise event
recorded during an event is known as the peak-noise level and is denoted as Lpeak.
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 4 of 12
Anot.her measure, known as the Community Noise Equivalence Level (CNEL) is
a 24-hour weighted average of noise levels. CNEL is calculated by. measuring noise over
a 24-hour period, adding a penalty of 5 dBA for noise that occurs during the evening
(e.g., 7:00 a.m. to 10:00 p.m.) and a 10 dBA penalty for noise that occur~ at night (e.g.,
1'0:90 p.m. to 7:00 a.m.), and then calculating the average noise level. This 'noise metrie . ".
works well for. measuring relatively const~int-noise levels; such ~~·freeway· noise. : .:'.;' .. ' .'. .... .. .
~ •• ',' ",' _' ... .' .':..... : "'. .:., ',' '. ~ " 44 • " : ~' • '. • •••• '0' ~'.,.~. "
~ .' Analysis Methodology . '. . . . -.. ":" .... ~:: .. -.~. i
Review of Current McClelian-Paloniar Airport FAR 150 Study. , "
ISE has performed a point-to-point parametric assessment of ,the CNEL noise .'
contours prepared for the subject project (Source: Final Report: Volume 1:-FAR '150 .
Noise Exposure Maps -McClellan-Palomar Airport,' KPMG Peat Marwick, May 1990) in :
order to verify the published contours and determine their adequacy"with respect to the
actual acoustical environment. . "
In order to predict these effects, ISE created a simplified acoustical model based
upon the 'INM solution methodology (Source: INM Technical Manl,Jal '5.1, Federal
Aviation Administration, Office of Environment and Energy, FAA-AEE-97-04, December
1997) to 1) validate or refute the proposed noise contours, and 2) extrapolate the results
to the subject property. No corrections for local topographic or atmospheric effects Wete
applied to the model, which is consistent with the original analysis approach.
Field Survey and Determination of Actual Contour Location
A rigorous field investigation of the BCS' property site and surrounding
community within the adjacent influence area of· the airport was performed between
3/10101 to 4/20101. The data, representing approximately 2,600 aggregate hours of
continuous monitoring and was performed utilizing remotely placed Larson Davis Model
700 ANSI Type 2 integrating sound level meters both on-an offsite. The selected offsite .
monitoring locations (ML's A though T), which were oeployed for roughly 24 hours at
each location in order to determine community noise levels, are shown below in Figure
3. .'
In addition, onsite monitoring was performed for an approxir:nate 720 hours (30
days) at each of three locations within the project extents. The monitoring' l.ocations
(ML's 1 though 3) are shown below in Figure 4. Photos of the onsite monitor locations
are shown in Figures 5a through d. .
It should be noted that monitoring location ML 1 corresponds to the published 65
dBA CNEL contour location as identified in the FAR 150 report. This location will be
utilized for comparison purposes with the published nois.e exposure maps.
' ..
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey-Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 5 of 12
Figure 3: Selected Monitoring Locations within Project Stu'dy Area
Figure 4: Fixed Onsite Monitoring Locations with BCS Property
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 6 of 12
View south towards ML 3 View south towards ML's 1, 2 & 3
Figures 5a though 5d: Onsite Monitoring Locations -BCS Property
All meters were mounted on tripods roughly five feet above the ground in <;>rder to
simulate the average height of the human ear above ground. All equipment was
calibrated before testing at ISE's acoustics and vibration laboratory to . verify
conformance with ANSI S1-4 1983 Type 2 and IEC 651 Type 2 standards. ..
~ Findings
Review of FAR 150 Study
The current noise exposure maps (circa 1995 horizon) for the McClellan-Palomar
airport were prepared by KPMG Peat Marwick in late 1989 with a publication date of
May 1990. KPMG was responsible for data collection while the task of calculation of the
actual noise exposure contours was delegated to Brown-Buntin and Associate.s.
.{ .. -'
. ~ '.
,i...<./' ~~ .:' .-
~; ... -~.... .
. ;-"
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 7 of 12
A review of the document found it to be consistent with the requirements
mandated under the Federal Aviation Administration FAR Part 150 standards. The
analysis provides the requisite 5-year horizon nois'e exposure contours, (1.995 levels).
These contours, which are based upon Version 3.9 of the FAA's Integrated Noise Model
(INM) show the location of the 65 dBA CNEL contour at a point crossing theBCS project
boundary as sh9wn in Figure 2. " . -
" As will be' d~monstrated' 'shortly, , th~ , actual ·-65:·dBA -CNEL -~ontour' 'lies
significantly outside the project boundary. The reasons for ,the differences are ,as follows: . .' ., -:. . ..' .
1. 'ver~ion 3.9' of the INM m~del 'is q~ite dated-c~mpared to the state ~f the-art: ~a~IY
versions of the model, such as this 'one, did not adequately account for path
interference, topography, or' meteorology,' nor were 'the databases of aircraft
emissions complete (complete Stage I and 'III data was not available). Currently the
FAA is planni~g the release of Version 6.2. of the model. '
2.' The FAR study assumed a shallow rate of climb for all VFR operations at the airp.ort.
The effect of this is the keep the aircraft noise emissions close to the ground for a
longer period of time, thereby producing larger impacts.
3. The FAR study utilized older aircraft emission data with higher run up and sideline
levels. This produces a greater extended noise contour.' "
4. No corrections for topography were taken. All receiver points were taken as lyiAg on '
the same spatial plane. The FAR study is a worst-case analytical study having a 3.0
dB/DO attenuation rate. As can be seen below (Figure 6), there is a significant
elevation difference between the BCS project site and the western end of the
runway. This path-length distance (known as slant range) was not taken into.
account. .
. ~ . . .
Figure 6: Cross-sectional Profile from BCS Center, to Runway Western E~ge .
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 8 of 12
5. No corrections for topographic or structural interference were taken. Source levels
such as run up and sideline emis,sions are propagated at ground' ,level to the
receiver. The figure below (Figure 7) shows the profile from. the center of .the ~CS '
site, to the center of the runway. It is cle~r that any pQint on t~e. run'way under thi$
configuration would not be visiQle, and it in fact currently blocked by industrial use ,
strLictures . ",", ' , '. ,'" " .... "::", .. : : ':,. ' . . , ~ ,: . --.'. ~. . '. ....., '
Figure 7: Cross-sectional Profile from BCS Center to Run~ayCenter
6. Uncertainties in the input parameters used for the modeling effort. This is a 'common
problem with all modeling efforts. CNEL contours generated by the INM model
typically have a variability of ± 10 percent under good modeling assumptions with the
estimates getting worse as the input assumptions become more variable. This fact is
acknowledged in the FAR study for the McClellan-Palomar airport on,Page 30 which
states, tI ••• CNEL contours should be regarded as a tool to assist in land use
planning around airports, but not as definite boundaries between fundamentally
different noise conditions ... ". Thus, the CNEL contours of the airport cannot, in the
strictest sense, be used for the exact determination of noise boundary division for
land planning situations.
Field Monitoring Results
The results of the pOint-to-point field verification of the noise exposure contours are
shown below in Table 1. The values of the measured CNEL values are given for each
location. As can be seen from the results, there is a high degree of variability in th~ actual
noise levels versus the analytical contours identified in the FAR study. These var!ances are
attributable to surface street vehicle traffic'and industrial/commercial noise (producing higher
than expected noise levels) and topographic and structural interference (p-rqducing lower than
expected noise levels). The experimentally derived noise exposure map of current aircraft
operations is shown in Figure 8. Based upon the data it appears that the FAR study is
conservative in its assessment of noise exposure to surrounding land uses.
Finally, the onsite noise levels are given in Table 2 below. The daily variation of
noise exposure onsite is plotted in Figures 9a through -c. Onsite CNEL levels were
found to range between 58 to 60 dBA. The dominant noise source affecting the project
site is Palomar Airport Road. .
.'
Ms. Kristine Zortman
. BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 9 of 12
TABLE 1: Community Noise Exposure Levels -McClellan-Palomar Airport
'<'Location' .... :. '-::;'-:-';~': ~ . '.: . '. D~te __ . :<.<: .~;'~~~~_~~:·.~;:~:~~~:~~~_9i!~~.~: ;~~i§i~~~~~.~*~~~g~!t~li~~Jl;~~~~{ -
MLA 3/1212001 3307.478' N 11718.066' W 62.8 Palomar.AirportRoad
" " .
MLB· . 3/13/2001 3307,681' N ·11717.790' W 67.7 . Small Planes
MLC 3/14/2001 3307.t67'N '11717.507' W 67.0 Small Planes
.,.-MLD 3/15/2001 ' 3307.917' N ',1171'7.295' W 67.4 Small Plimes'
MLE 3/16/2001 3307.734' N 11717.106' W .71.6 ' Small Planes .' . 'S';;ail 'pi~me~ ML r= 3/19/2001 3307.767' N 11716.914'W 70.8 -
MLG 3/20/2001 3307.780' N 11716.803' W 70.6' Helicopter
MLH 3/21/2001 3307.789' N 11716.771'W 69.4 HelicopterlSmall Plane~
MLI 3/22/2001 3307.817' N 11716.577' W 70.4 HelicopterIS~af! Plane's "
MLJ 3/23/2001 3308.070' N 11716.714'W 64.6 He~icop~erISmall PI.anes
MLK 3/26/2001' 3307.883' N 11716.158' W· 66.0 Small Planes Landing
MLL 3/27/2001 3307.754' N 117 16.143' W 65.1 Small Planes 1 Traffic
MLM 3/28/2001 3307.660' N 11716.339' W 71.1 Small Planes 1 Traffic
MLN 3/29/2001 3307.470' N 11716.407' W 61.6 Small Planes
MLO 3/30/2001 3307.246' N 11716.689' W 59.7 Small Planes
MLP 41212001 3307.406' N 11716.771' W 61.6 Small Planes
MLQ 4/3/2001 3307.560' N 11717.117'W 73.8 Ajrcraft Ops
MLR 4/4/2001 3307.598' N 11717.479' W 72.6 Aircraft Ops
MLS 4/5/2001 3307.273' N 11717.312' W 61'.7 Small Planes
MLT 4/6/2001 3307.351' N 11717.596' W 68.0 Palomar Airport Rd.
. Me.asurements performed by ISE between 3/12101 to 4/6/01.
TABLE 2: Current Aggregate Noise Exposure Levels -BCS Property Site
.J '. Site.
ML1
ML2
ML3
57.3
55.7
51.6
.. ,
Morihorincj .Locations:
720-Ho·ur. Agg~egate 'Average N'oise l:ev~i'Descr.iptors~ln 'dBA :"::~,:;5.:-:-Ji';
": ":.:. \" .' "',. ".: .: ~ :. ~ '-. -':'" ,'::.1, :!. ~. '-, '~:' ;.~': ~~;:~~~~~:i i~ .):~~~' '~:~:;':::~f;':'~~ :~. ~~_;f~~~:'_;~::~~~:j-
. Lmax' c Lmm ",' L10 '. ':-:> -·,L50' "··~.:·:j/::;,L90 !.;:.,}J;+'·~l;CNEl-V'!~; ~ ~~"" .' ",' ,.J',. ~ .' .... ' ., ... : '.~ : •• ~ J":~'''''.~~''',:':: .. ' ,1, .. l, ....... ~, .. ·~?(-~~· ... :;fi;~-~ ... ::;~if;.':.:::'!{ .. ~~
79.5 42.4 60.0 50.8 49.5 .59.9
78.1 41.0 66.6 49.7 ,48.5' ' . 59.0
72.8 40.3 58.8 46.9 46.4 . 57.8 .
o ML 1 GPS: 33°7.299'N x 117'17:859'W, EPE' 10 ft. o ML2 GPS: 33°7.27iN x 117'17.850'W, EPE 10ft.
o ML 3 GPS: 33°7.23iN x 117'17.880'W, EPE 10 ft.
. . "
Measurements performed by ISE between 3/16/01 to 4/16/01. EPE = Estima.ted Position Error .. :
,", ".
. ,
.. .:
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey-Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 10 of 12
Figure 8: Experimentally Derived Noise Exposure Map (Source ISE -4/01).
100.0
90.0
80.0
< III 70.0 ...
.5 ... 11. UI SO.O ! '" .. .. 50.0 • ::e
40.0
30.0
20.0
Figure 9a: Time Variation of Onsite Noise Exposure at ML 1
Ms. Kristine Zortman
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 11 of 12
100
90
80
~ 70 'tI
.S
....I Ii. 1/1 60 'tI ! '" .. " 50 .. :Ii
40
30
20
Time Index (day/hour)
Figure 9b: Time Variation of Onsite Noise Exposure at ML 2
1000
,
90,0 .... ~.
800
700
600
500
400
300
Time Index (day/hour)
Figure 9c: Time Variation of Onsite Noise Exposure at ML 3
.;;-""
'.'
i ," ~ ... _ ................ .
:: I J
Ms. Kristine Zortman e
BCS FAR 150 Site Compliance Survey -Carlsbad, CA
ISE Report #01-014
April 27, 2001
Page 12 of 12
~ Conclusions I Recommendations
Ambient noise levels within the BCS project site were found to range between 58
and 60 dBA CNEL. Palomar Airport Road was identified as the (jominant noise sOl,Jrce
affecting the site. No unusual traffic patterns were observed in the data from either'the "
airport or .Palomar Airport Road. The measured leivels are consJstent with the' observed .
'community setting.' ' ,.'. ., .' .. .. .
. Since the aggrE;lgate of traffic and aircraft nois.e did not e~c~ed 65 dBA CNE~,
. there i.s no physical way that the aircraft-orily contribution could exceed this . level ~given' ,
the currerit flight operations. Thus, the project site does not empirically reside withih the
.. 65-dBA CNEL. contour of McClellan Palomar Airport. The contour vc;:llues shown in the. "
FAR 150 study for the airport would therefore repres~nt a worst-case condition and ,,: .. '
would not be indicative of the project area noise environment. '
Should you have any questions regarding the findings identified herein, please
do not hesitate to contact me at (619) 640-9379.
Sincerely,
Rick Tavares
President I Principal
Investigative Science and Engineering, Inc.
Cc: Jeremy Louden, ISE