HomeMy WebLinkAboutCT 00-19; Carlsbad Promenade; Tentative Map (CT) (4)Investigative Science and Engineenng, inc.
3545 Catnino Del Rio Soutti, Suite E Piiotie/Fax: 619-640-9379 / 619-640-0763
San Diego. CA 92108-4003 viiww.investigative-science.com
October 8, 2000
Mr. Anthony Badeaux
Koll Development Group
4275 Executive Square, Suite 240
La Jolla, CA 92037
Re: Carisbad Promenade Residential IDevelopment Acoustical Study, San Diego, CA
(ISE Report #00-072)
Dear Mr. Badeaux:
At your request, Investigative Science and Engineering (ISE) were directed to
investigate potential noise impacts to the proposed Carlsbad Promenade Residential
Development located in Carlsbad, California. An acoustical survey of the site was
performed on September 22, 2000. The results of that survey, as well as predicted future
sound levels at the site, are presented in this letter report.
Introduction and Definitions
Existing Site Characterization
The project site consists of approximately 30.9 acres (APN 214-550-01, 215-070-
13, 26) located within the City of Carlsbad, California (refer to Figure 1). The site is
bordered to the south by Poinsettia Lane, to the west by Aviara Parkway, to the north by
open space, and to the east by open space / single-family residential development. The
project site currently resides as vacant disturbed land. The general site configuration is
shown below in Figures 2a through -c.
The topography of the site is essentially flat containing moderate slopes tending
towards the northeast (see Figure 3) and elevations onsite ranging between 280 feet
above mean sea level (MSL) at the northeast corner of the project site to 310 feet MSL
along Aviara Parkway.
Mr. Anthony Badeaux
Carlsbad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 2
Figure 1: Project Vicinity Map (Thomas Guide Page 1127, Grid B5)
Aviara Parkway / Poinsettia Lane
Intersection
Project Site as Viewed from
Intersection
Typical Site as Viewed towards
North
Figures 2a through -c: Site Configuration Photos - Carlsbad Promenade Lot
Mr. Anthony Badeaux
Carlsbad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 3
1000 2000 3000 4000 FEET
Figure 3: Project Area Topography (USGS 7.5 Encinitas Quadrangle 1:12000)
Acoustical Definitions
Noise is generally defined as unwanted or annoying sound that is typically
associated with human activity and which interferes with or disrupts normal activities.
Although exposure to high noise levels has been demonstrated to cause hearing loss,
the principal human response to environmental noise is annoyance. The response of
individuals to similar noise events is diverse and influenced by the type of noise, the
perceived importance of the noise and its appropriateness in the setting, the time of day,
and the sensitivity of the individual hearing the sound.
Airborne sound is a rapid fluctuation of air pressure above and below
atmospheric levels. The loudest sounds 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 represent the
acoustic intensity of a particular sound on a linear scale becomes unwieldy. Because 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
Mr. Anthony Badeaux
CartslMid Promenade Residential Devetopment Acoustical Study, San Diego,
ISE Report #00-072
October 8,2000
Page 4
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 single
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 frequendes 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 includes 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 conglomeration 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. It
is the 'equivalent' constant sound level that would have to be produced by a given
source to equal the average of the fluctuating level measured. For traffic-related
acoustical studies, the monitoring interval is generally taken as one-hour.
To describe the time-varying character of environmental noise, the statistical
noise descriptors LIO, L50, and L90 are commonly used. They are the noise levels
equaled or exceeded during 10 percent, 50 percent, and 90 percent of a stated time.
Sound levels associated with the LIO typically describe transient or short-term events,
while levels associated with the L90 describe the steady state (or most prevalent) noise
conditions. In addition, it is often desirable 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 value obtained for a
particular monitoring location is often called the acoustic floor for that location.
Another sound measure employed by the State of California (and the City of
Carlsbad) is known as the Community Noise Equivalence Level (CNEL) is defined as the
"A" weighted average sound level for a 24-hour day. It is calculated by adding a 5-
decibel penalty to sound levels in the evening (7:00 p.m. to 10:00 p.m.), and a 10-
decibel penalty to sound levels in the night (10:00 p.m. to 7:00 a.m.) to compensate for
the increased sensitivity to noise during the quieter evening and nighttime hours.
Applicable Significance Criteria
Citv of Carlsbad
The Noise Element of the City of Carlsbad identifies certain sound levels that are
compatible with various land uses. According to the City of Carlsbad Draft Noise
Guidelines Manual, sound levels up to 60 dBA CNEL are compatible with residential
Mr. Anthony Badeaux
Carlsbad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 5
land uses. The City also requires an interior noise study (compliant with State of
California CCR Title 24 standards) where exterior exposure is in excess of the above
land use criteria.
Proposed outdoor areas contained within the Carlsbad Promenade development
that would be classified as usable outdoor living space, would include rear and side yard
areas of all developable lots.
State of California CCR Title 24
The California Code of Regulations (CCR), Title 24, Noise Insulation Standards,
states that single- and multi-family dwellings, hotels, and motels located where the
CNEL exceeds 60 dBA, must obtain an acoustical analysis showing that the proposed
design will limit interior noise to less than 45 dBA CNEL. Worst case noise levels, either
existing or future, must be used for this determination. Future noise levels must be
predicted at least ten years from the time of building permit application. The City of
Carlsbad has adopted the CCR Title 24 standards.
Analysis Methodology
Existinq Conditions Field Survey
A Larson Davis Model 700 ANSI Type 2 integrating sound level meters was used
as the data collection device. The meter was placed at a point corresponding to the
approximate rear yard area of Lot #14 at the intersection of Aviara Parkway and
Poinsettia Lane (refer to Figures 4a and -b).
The meter was mounted on a tripod roughly five feet above the ground in order to
simulate the average height of the human ear above ground. The measurements were
performed on September 22, 2000. 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.
Figures 4a and -b: Ambient Remote Noise Monitoring Location Photos
Mr. Anthony Badeaux
Carlsbad Promenade Residential Devetopment Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 6
Future Acoustical Environment Modeling
The Caltrans Sound 32 Traffic Noise Prediction Model with California
(CALVENO) noise emission factors {based on FHWA RD-77-108 and FHWA/CA/TL-
87/03 star}dards) was used to calculate future onsite vehicular traffic noise levels. Model
input included a digitized representation of the project site, Poinsettia Lane and Aviara
Parkway, as well as any available local site topography, future Average Daily Traffic
(ADT) volume, vehicle mix, and receptor elevations. The roadway and site topography
elevations were obtained from the project engineering grading plans {Source: Tentative
Map for Carlsbad Promenade, O' Day Consultants, 8/00). Model output consisted of
peak hour energy-mean A-weighted sound levels (or Leq-h) for each receptor examined.
Receptor elevations were considered five feet above the appropriate floor (pad)
elevation and v/ere taken in the center of the proposed rear yard areas of each lot. The
model assumed a "hard" site sound propagation rule (i.e., a 3-dBA loss per doubling of
distance from roadway to receiver) in accordance with City/Caltrans practices and the
observed topography of the surrounding terrain. The model also considered the
attenuation due to the slope topography adjacent to the project site. Second floor
receptor areas were modeled at 20 feet above the respective pad elevation.
Findings
Ambient Sound Measurement Results
Testing conditions during the monitoring period were overcast with an average
barometric pressure reading of 29.90 in-Hg, an average westerly wind speed of 5 to 8 miles
per hour (MPH), and an approximate mean temperature of 70 degrees Fahrenheit. The
results of the sound level monitoring are shown below in Table 1. The values for the energy
equivalent sound level (Leq), the maximum and minimum measured sound levels (Lmax and
Lmin), and the statistical indicators LIO, L50, and L90, are given for each monitoring location.
Measurements collected at the monitoring location (ML 1) reflect the typical
sound levels associated with the community setting observed and the topography of the
surrounding terrain. The hourly average sound level (or Leq-h) recorded over the
monitoring period was 58.5 dBA and was due primarily to moderate afternoon peak hour
vehicular traffic activity along Poinsettia Lane and Aviara Parkway. The background
noise level, as indicated by the L90 metric was 51.5 dBA indicating the semi-rural nature
of the project site. The acoustic floor for the site was 49.5 dBA.
Mr. Anthony Badeaux
Carlslrad Promenade Residential Devetopment Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 7
Table 1: Measured Ambient Sound Levels - Carisbad Promenade Property
1-Hour Noise Level Descriptors in dBA
Site Start Time Leq Lmax Lmin LIO L50 L90
ML 1 3:30 p.m. 58.5 69.0 49.5 62.0 59.0 51.5
Monitoring Locations:
• ML 1: Meter positioned at Lot #1 area of project site. GPS: 33°06.742'N X 117°17.745 W
EPE 10 ft.
Measurements perfonned by ISE on September 22, 2000. EPE = Estimated Position Error.
Future Traffic Noise Impacts
The primary source of future traffic noise near the project would be from
Poinsettia Lane and Aviara Parkway which are directly adjacent to the projects southern
and western boundaries. Future year traffic volumes for Poinsettia Lane is projected to
be as high as 14,000 ADT while Aviara Parkway is projected to be 10,000 ADT {Source:
SANDAG Series 9 Year 2020 Traffic Prediction Model, 10/00). The future projected
speed limit for both roads is 50 MPH.
For this study, peak hour traffic values were calculated for a 10% traffic flow
pattern and a 96/2/2 (automobiles/medium/heavy vehicles) percent mix in accordance
with the observed distribution for this roadway. For peak hour traffic percentages
between approximately 8 and 12 percent (and an LOS between A and C), the energy-
mean A-weighted sound level is statistically equivalent to the 24-hour Community Noise
Equivalent Level (CNEL). Outside this range, a maximum variance of up to two dBA
occurs between Leq-h and CNEL.
The results of the acoustical modeling are shown below in Table 2. Based upon
the findings, the predicted future traffic noise could approach levels as high as 59.0 dBA
within rear yard areas of Lots # 1 through 24 of the proposed development. No exterior
noise mitigation (i.e., noise walls) would be required for this project.
Second story areas of the same lots (shown in bold red text) would be exposed
to noise levels in excess of the Title 24 60-dBA CNEL threshold and would require
require mitigation in the form of specialized window treatments (such as dual glazing,
etc). An interior noise assessment designed to reduce noise levels to 45 dBA CNEL
would be required upon completion of the projects architectural plans. No additional
noise mitigation would be required.
Mr. Anthony Badeaux
Carlsbad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Pages
Table 2: Transportation Noise Levels - Carlsbad Promenade Property
Receptor Lot No. Ground Level (Unmitigated} Second Story Level
1 51.9 62.4
2 52.4 64.1
3 54,7 64.8
4 56.3 64.7
5 54.8 63.9
6 52.7 64.0
7 52.0 62.5
8 52.5 62.3
9 52.7 62.4
10 53.6 63.8
11 53.6 63.5
12 54.6 64.3
13 55.9 65.1
14 59.0 67.6
15 58.2 66.6
16 57.8 66.5
17 57.4 66.4
18 57.8 66.3
19 56.7 65.7
20 57.1 66.1
21 58.5 66.6
22 58.6 66.6
23 58.3 66.4
24 58.7 66.5
Aircraft Noise Impacts
The proposed project site currently does not lie within the 60 dBA CNEL or
greater contour for any airfield. No aircraft-related noise impacts are therefore expected.
Conclusions / Recommendations
Predicted noise levels for unmitigated ground floor receptor areas would not
exceed the City's allowable threshold for lots facing Aviara Parkway or Poinsettia Lane.
No exterior noise mitigation would be required.
Sensitive second floor interior receptor areas for the same lots (i.e., those facing
Aviara Parkway or Poinsettia Lane) would be exposed to noise levels exceeding the
allowable 60-dBA CNEL impact threshold. An interior noise assessment designed to
reduce noise levels to 45 dBA CNEL would t>e required upon completion of the projects
architectural plans. No additional noise mitigation would be required.
Mr. Anthony Badeaux
Carlsbad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 9
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/Principal
Investigative Science and Engineering, Inc.
Cc: Sergio Carnalla, ISE
Attachments: Sound 32 Input Deck
Mr. Anthony Badeaux
Carlsbad Promenade Residential Devetopment Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 10
S32 Input Deck - Unmitigated
CARLSBAB PROMENADE - KOLL DEVELOPMENT (UNMITIGATED)
T-PEAK HOUR TRAFFIC CONDITIONS, 1
960 , 50 , 20 , 50 , 20 , 50
T-PEAK HOUR TRAFFIC CONDITIONS, 2
1344 , 50 , 28 , 50 , 28 , 50
L-AVIARA PARKWAY, 1
N,-23,1467,283,AP-1
N,110,1314,285,AP-2
N,210,1160,285,AP-3
N,284,1020,284,AP-4
N,335,880,284,AP-5
N,392,663,280,AP-6
N,459,427,272,AP-7
N,531,196,270,AP-8
L-POINSETTIA LANE, 2
N,358,203,269,PL-1
N,516,251,270,PL-2
N,722,320,272,PL-3
N,940,411,274,PL-4
N,1187,563,278,PL-5
N,1340,714,281,PL-6
N,1472,848,286,PL-7
N,1607,982,295,PL-8
B-SLOPE EDGE, 1,1,0,0
347,1283,305,305,SLOPE-1
321,1286,305,305,SLOPE-2
313,1204,305,305,SLOPE-3
357,1141,305,305,SLOPE-4
385,1088,302,302,SLOPE-5
408,1036,300,300,SLOPE-6
42 5,977,307,307,SLOPE-7
445,923,309,309,SLOPE-8
455,870,307,307,SLOPE-9
507,830,3 07,307,SLOPE-10
B-SLOPE EDGE, 2,1,0,0
507,830,3 07,307,SLOPE-10
491,775,307,307,SLOPE-11
509,708,305,305,SLOPE-12
522,650,3 04,304,SLOPE-13
536,593,302,302,SLOPE-14
549,535,300,300,SLOPE-15
595,389,298,298,SLOPE-16
655,412,299,299,SLOPE-17
717,426,299,2 99,SLOPE-18
774,447,298,298,SLOPE-19
B-SLOPE EDGE, 3,1,0,0
774,447,2 98,298,SLOPE-19
847,478,2 98,298,SLOPE-2 0
916,515,2 97,2 97,SLOPE-21
981,547,2 98,298,SLOPE-22
1040,587,299,299,SLOPE-23
Mr. Anthony Badeaux
Carlsljad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8,2000
Page 11
1115,648,299,299,SLOPE-24
1166,686,300,300,SLOPE-25
1214,723,300,300,SLOPE-26
1267,784,300,300,SLOPE-27
1265,821,300,300,SLOPE-28
B-SLOPE EDGE, 4,1,0,0
1265,821,300,300,SLOPE-28
1229,845,3 00,3 00,SLOPE-29
R, 1 , 65 ,10
346,1230,301,R-l
R, 2 , 65 ,10
373.1175.301, R-2
R, 3 , 65 ,10
394.1121.302, R-3
R, 4 , 65 ,10
419.1069.302, R-4
R, 5 , 65 ,10
446.1018.303, R-5
R, 6 , 65 ,10
462,961,304,R-6
R, 7 , 65 ,10
484.904.304, R-7
R, 8 , 65 ,10
515.857.305, R-8
R, 9 , 65 ,10
532.795.305, R-9
R, 10 , 65 ,10
545.743.306, R-10
R, 11 , 65 ,10
559,687,305,R-11
R, 12 , 65 ,10
572,630,305,R-12
R, 13 , 65 ,10
579,572,304,R-13
R, 14 , 65 ,10
609,448,304,R-14
R, 15 , 65 ,10
679,452,304,R-15
R, 16 , 65 ,10
737,473,304,R-16
R, 17 , 65 ,10
802,501,303,R-17
R, 18 , 65 ,10
866,530,303,R-18
R, 19 , 65 ,10
926.570.302, R-19
R, 20 , 65 ,10
989.604.303, R-20
R, 21 , 65 ,10
1066.645.304, R-21
R, 22 , 65 ,10
1120,688,304,R-22
R, 23 , 65 ,10
Mr. Anthony Badeaux
Cartstrad Promenade Residential Development Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 12
1168,733,305,R-23
R, 24 , 65 ,10
1219,776,305,R-24
C,C
Mr. Anthony Badeaux
Carlsbad Promenade Residential Devetopment Acoustical Study, San Diego, CA
ISE Report #00-072
October 8,2000
Page 13
S32 Input Deck - Second Story Areas
CARLSBAD PROMENADE - KOLL DEVELOPMENT (SECOND STORY)
T-PEAK HOUR TRAFFIC CONDITIONS, 1
960 , 50 , 20 , 50 , 20 , 50
T-PEAK HOUR TRAFFIC CONDITIONS, 2
1344 , 50 , 28 , 50 , 28 , 50
L-AVIARA PARKWAY, 1
N,-23,1467,283,AP-1
N,110,1314,285,AP-2
N,210,1160,285,AP-3
N,284,1020,284,AP-4
N,335,880,284,AP-5
N,392,663,280,AP-6
N,459,427,272,AP-7
N,531,196,270,AP-8
L-POINSETTIA LANE, 2
N,358,203,269,PL-1
N,516,251,270,PL-2
N,722,320,272,PL-3
N,940,411,274,PL-4
N,1187,563,278,PL-5
N,1340,714,281,PL-6
N,1472,848,286,PL-7
N,1607,982,295,PL-8
B-SLOPE EDGE, 1,1,0,0
347,1283,305,305,SLOPE-1
321,1286,305,305,SLOPE-2
313,1204,305,305,SLOPE-3
357,1141,305,305,SLOPE-4
385,1088,302,302,SLOPE-5
408,1036,300,300,SLOPE-6
425,977,307,307,SLOPE-7
445,923,3 09,3 09,SLOPE-8
455,870,307,307,SLOPE-9
507,830,3 07,307,SLOPE-10
B-SLOPE EDGE, 2 , 1 , 0,0
507,830,3 07,307,SLOPE-10
491,775,307,307,SLOPE-11
509,708,3 05,305,SLOPE-12
522,650,3 04,3 04,SLOPE-13
536,593,302,302,SLOPE-14
549,535,3 00,30Q,SLOPE-15
595,389,298,298,SLOPE-16
655,412,2 99,299,SLOPE-17
717,426,299,299,SLOPE-18
774,447,298,298,SLOPE-19
B-SLOPE EDGE, 3,1,0,0
774,447,298,298,SLOPE-19
847,478,298,298,SLOPE-20
916,515,297,297,SLOPE-21
981,547,298,298,SLOPE-22
1040,587,299,299,SLOPE-23
Mr. Anthony Badeaux
Carlsbad Promenade Residential Devetopment Acoustical Study, San Diego, CA
ISE Report #00-072
October 8, 2000
Page 14
1115,648,299,299,SLOPE-24
1166,686,300,300,SLOPE-25
1214,723,300,300,SLOPE-26
1267,784,300,300,SLOPE-27
1265,821,300,300,SLOPE-28
B-SLOPE EDGE, 4,1,0,0
1265,821,300,300,SLOPE-28
1229,845,300,300,SLOPE-29
R, 1 , 65 ,10
346,1230,316.,R-1
R, 2 , 65 ,10
373,1175,316.,R-2
R, 3 , 65 ,10
394,1121,317.,R-3
R, 4 , 65 ,10
419,1069,317.,R-4
R, 5 , 65 ,10
446,1018,318.,R-5
R, 6 , 65 ,10
462,961,319.,R-6
R, 7 , 65 ,10
484,904,319.,R-7
R, 8 , 65 ,10
515,857,320.,R-8
R, 9 , 65 ,10
532,795,320.,R-9
R, 10 , 65 ,10
545,743,321.,R-10
R, 11 , 65 ,10
559,687,320.,R-11
R, 12 , 65 ,10
572,630,320.,R-12
R, 13 , 65 ,10
579,572,319.,R-13
R, 14 , 65 ,10
609,448,319.,R-14
R, 15 , 65 ,10
679,452,319.,R-15
R, 16 , 65 ,10
737,473,319.,R-16
R, 17 , 65 ,10
802,501,318.,R-17
R, 18 , 65 ,10
866,530,318.,R-18
R, 19 , 65 ,10
926,570,317.,R-19
R, 20 , 65 ,10
989,604,317.,R-20
R, 21 , 65 ,10
1066,645,319.,R-21
R, 22 , 65 ,10
1120,688,319.,R-22
R, 23 , 65 ,10
Mr. Ainthony Badeaux ^ o r. r-K Carlsbad Promenade Residential Devetopment Acoustical Study, San Diego, OA
ISE Report #00-072
October 8.2000
Page 15
1168,733,320.,R-23
R, 24 , 65 ,10
1219,776,320.,R-24
C,C