HomeMy WebLinkAboutGPA 15-02; OCEAN VIEW POINT; NOISE STUDY; 2015-06-23RE.CE\VE.D
NOISE STUDY J\Jl-l 14 2015
"CARLSBAD
CIT~~;NG DIVISION
Oceanview Carlsbad Tentative MapLA
Residential Development
Carlsbad, CA
Project Proponent:
Mrs. Gayl Hynek
8541 Mossrose Way
Gilroy, CA 95020
cf o Nick Doenges
J. Whalen Associates, Inc.
1660 Hotel Circle N, Ste. 725
5an Diego, CA 92108
Prepared by:
Jeremy Louden
Ldn&tln#lllfng.lne..
42428 Chisolm Trail
Murrieta, CA 92562
760-473-1253
June 23, 2015
Project: 1572-03 Oceanview Cartsbad Noise Report
TABLE OF CONTENTS
TABLE OF CONTENTS .......................................................................................................................................... II
LIST OF FIGURES ................................... , ............................................................................................................. II
LIST OF TABLES ................................................................................................................................................... II
GLOSSARY OF TERMS ........................................................................................................................................ Ill
EXECUTIVE SUMMARY ...................................................................................................................................... IV
1.0 PROJECT INTRODUCTION ........................................................................................................................... 1
1.1 PURPOSE OF THIS STUDY ........... . .. .......... 1
1.2 PROJECT LOCATION ........ . .. ......... 1
1.3 PROJECT SmlNG .... . ••···••••••••··•••••••••····• ............ 1
2.0 ACOUSTICAL FUNDAMENTALS ................................................................................................................... 4
3.0 SIGNIFICANCE THRESHOLDS AND STANDARDS ........................................................................................... S
4.0 NOISE ENVIRONMENT ............................................................................................................................... 6
4.1 EXISTING NOISE ENViRONMENT0NSITE ............................................... . .. ..... 6
4.2 AIRPORT RELATED NOISE .. . ............. 8
4.3 FUTURE NOISE PREDICTION METHODOLOGY .. ··················•· ........................... 8
4.4 FINDINGS AND MITIGATION ........ . ••••••••••••••• .. 9
LJST OF FIGURES
FIGURE l•A: PROJECT VICINITY MAP ................................................................................................................... 2
FIGURE 1-8: PROJECT SITE PLAN ......................................................................................................................... 3
FIGURE 4-A: AMBIENT MONITORING LOCATION ................................................................................................. 7
FIGURE 4-8: PALOMAR AIRPORT NOISE CONTOURS ............................................................................................ 8
FIGURE 4-C: FUTURE CUMULATIVE NOISE LEVELS .............................................................................................. 10
IJST OF TABLES
TABLE 4-1: MEASURED AMBIENT NOISE LEVELS .................................................................................................. 6
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GLOSSARY OF TERMS
Sound Pressure Level {SPL): a ratio of one sound pressure to a reference pressure (lref) of
20 µPa. Because of the dynamic range of the human ear, the ratio is calculated logarithmically
by 20 log (L/L,,,)
A-weighted Sound Pressure Level (dBA): Some frequencies of noise are more noticeable
than others. To compensate for this fact, different sound frequencies are weighted more.
Minimum Sound Level (Lm1n): Minimum SPL or the lowest SPL measured over the time
interval using the A-weighted network and slow time weighting.
Maximum Sound Level (I.max): Maximum SPL or the highest SPL measured over the time
interval the A-weighted network and slow time weighting.
Equivalent sound level (Leci): the true equivalent sound level measured over the run time.
Leq is the A-weighted steady sound level that contains the same total acoustical energy as the
actual fluctuating sound level.
Day Night sound Level (LON}: Representing the Day/Night sound level, this measurement is
a 24 -hour average sound level where 10 dB is added to all the readings that ocrur between 10
pm and 7 am. This is primarily used in community noise regulations where there is a 10 dB
"Penalty" for night time noise. Typically LDN's are measured using A weighting.
Community Noise Exposure Level (CNEL}: The accumulated exposure to sound measured
in a 24-hour sampling interval and artificially boosted during certain hours. For CNEL, samples
taken between 7 pm and 10 pm are boosted by 5 dB; samples taken between 10 pm and 7 am
are boosted by 10 dB.
Octave Band: An octave band is defined as a frequency band whose upper band-edge
frequency is twice the lower band frequency.
Third-Octave Band: A third-octave band is defined as a frequency band whose upper band-
edge frequency is 1.26 times the lower band frequency.
Response Time (F,S,I}: The response time is a standardized exponential time weighting of
the input signal according to fast (F), slow (S) or impulse (I) time resJX)nse relationships. Time
response can be described with a time constant. The time constants for fast, slow and impulse
resJX)nses are 1.0 seconds, 0.125 seconds and 0.35 milliseconds, respectively.
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EXECUTIVE SUMMARY
This noise study has been completed to determine the noise impacts associated with the
development of the proposed residential project. The project known as Oceanview cartsbad
Tentative Map Residential Development consists of thirteen (13) new single-family units. The
project site is located at the end of Twain Avenue, north of Faraday Avenue, east of cannon
Road in the City of Carlsbad CA.
Airport Noise Levels
The McClellan-Palomar Airport Land Use Compatibility Plan (ALUCP) adopted March 4, 2010 was
compared to the project site location. According to adopted ALUCP the project site is located
outside the 60 dBA CNEL. Therefore, no additional mitigation is required to meet the City of
carlsbad's 60 dBA CNEL exterior noise standard for outdoor usable space.
Transoortation Noise Rndinos
The primary source of noise impacts to the project site will be background vehicular noise from
cannon Road located over 2,000 feet west of the project site and Faraday Avenue located down a
large slope is over 600 feet west, south, and east of the project site. Based on the exterior noise
model, the worst-case cumulative noise level from the roadways was found to be 52.8 dBA CNEL
at the site.
Combined Aircraft and Roadway Noise Levels
Based on the exterior noise model for the roadway the worst-case exterior noise level at the
building fac;ade of the site is 52.8 dBA O\IEL. The airJX)rt related activities at the site is well below
60 dBA CNEL based on the McClellan-Palomar Airport Land Use Compatibility Plan (ALUCP) noise
contours. To be conservative, a worst case noise level of 56.1 dBA CNEL was utilized based on the
ambient noise measurements. The combination of the roadway and airuaft activities was
combined and yields a cumulative future noise level of approximately 58 dBA CNEL at the project
site. Based upon these findings the future noise levels were found to be at or below 60 dBA CNEL
and no noise mitigation is required to comply with the City of C.arlsbad Noise standards. The
building facades would also be below the 60 dBA CNEL. Therefore, no interior mitigation is
required.
Project Related Roadway Noise Levels
The combined existing plus project traffic volumes would equate to an overall worst-case noise
level of 49 dBA CNEL. This is well below the City's 60 dBA CNEL threshold and no project related
traffic noise impacts would occur.
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1.0 PROJECT INTRODUCTION
1.1 Purpose of this Study
Toe pur~e of this Noise study is to determine potential onsite traffic noise impacts created
from nearby cannon Road and Faraday Avenue. Should impacts be determined, the intent of
this study would be to recommend suitable mitigation measures to bring those impacts to a
level that would be considered less then significant.
1.2 Project Looltion
The proposed project is located within the City of carlsbad, CA More specifically, the project
site is located at the end of Twain Avenue, north of Faraday Avenue, east of cannon Road in
the City of carlsbad CA. Access to the project site is from Twain Avenue. A general project
vicinity map is shown in Figure 1-A on the following page.
1.3 Project Setting
The proposed project consists of 13 single-family residences. The existing site conditions are
characterized as undisturbed land. Residential uses exist adjacent to the site to the north. A
project site plan is shown in Figure 1-B on Page 3 of this report.
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Figure 1-A: Project Vicinity Map
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2.0 ACOUSTICAL FUNDAMENTALS
Noise is defined as unwanted or annoying sound which interferes with or disrupts normal
activities. Exposure to high noise levels has been demonstrated to cause hearing loss. The
individual human response to environmental noise is based on the sensitivity of that individual,
the type of noise that occurs and when the noise occurs. Sound is measured on a logarithmic
scale consisting of sound pressure levels known as a decibel (dB). The sounds heard by
humans typically do not consist of a single frequency but of a broadband of frequencies having
different sound pressure levels. The method for evaluating all the frequencies of the sound is to
apply an A-weighting to reflect how the human ear responds to the different sound levels at
different frequencies. The A-weighted sound level adequately describes the instantaneous noise
whereas the equivalent sound level depicted as Leq represents a steady sound level containing
the same total acoustic.al energy as the actual fluctuating sound level over a given time interval.
The community Noise Equivalent Level (CNEL) is the 24 hour A-weighted average for sound,
with corrections for evening and nighttime hours. The corrections require an addition of 5
decibels to sound levels in the evening hours between 7 p.m. and 10 p.m. and an addition of 10
decibels to sound levels at nighttime hours between 10 p.m. and 7 a.m. These additions are
made to account for the increased sensitivity during the evening and nighttime hours when
sound appears louder.
A vehicles noise level is from a combination of the noise produced by the engine, exhaust and
tires. The cumulative traffic noise levels along a roadway segment are based on three primary
factors: the amount of traffic, travel speed, and the vehicle mix ratio or number of medium and
heavy trucks. The intensity of traffic noise is increased by higher traffic volumes, greater speeds
and increased number of trucks.
Because mobile/traffic noise levels are c.alculated on a logarithmic sc.ale, a doubling of the traffic
noise or acoustic.al energy results in a noise level increase of 3 dBA. Therefore the doubling of
the traffic volume, without changing the vehicle speeds or mix ratio, results in a noise increase
of 3 dBA. Mobile noise levels radiant in an almost oblique fashion from the source and drop off
at a rate of 3 dBA for each doubling of distance under hard site conditions and at a rate of 4.5
dBA for soft site conditions. Hard site conditions consist of concrete, asphalt and hard pack dirt
while soft site conditions exist in areas having grade changes, landsc.aped areas and vegetation.
On the other hand, fixed sources radiate outward uniformly as it travels away from the source.
Their sound levels attenuate or drop off at a rate of 6 dBA for each doubling of distance.
The most effective noise reduction methods consist of controlling the noise at the source,
blocking the noise transmission with barriers or relocating the receiver. Any or all of these
methods may be required to reduce noise levels to an acceptable level.
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3.0 SIGNIFICANCE THRESHOLDS AND STANDARDS
The City of carlsbad's Noise Guidelines Manual (1995) requires that all exterior sensitive areas
shall limit noise exposure. For noise sensitive residential land uses, the City has adopted a
policy which has established a "normally acceptable" exterior noise level goal of 60 dBA CNEL
for the outdoor areas and an interior noise level of less than 45 dBA CNEL. For residential
properties identified as requiring a noise study, the study shall document the projected
maximum exterior noise level and mitigate the projected exterior noise level to a maximum
allowable noise level as identified in the Noise Guideline Manual.
california Noise Insulation Standards (california Ccxle of Regulations, Title 24) and the City of
carlsbad Noise Element establish an interior noise standard of 45 dBA for residential structures.
Acoustical studies must be prepared for residential structures that are proposed to be located
within the Community Noise Equivalent Level (CNEL) noise contours of 60 dBA or greater. In
addition, the Oty requires residential structures located within the CNEL noise contours of 60 or
greater to prepare an acoustical study. The studies must demonstrate that the building is
designed to reduce interior noise to 45 dBA or lower (CNEL).
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4.0 NOISE ENVIRONMENT
4.1 Existing Noise Environment Onsite
Noise measurements were taken using a Larson-Davis Model LxT Type 1 precision sound level
meter, programmed, in "slow" mode, to record noise levels in "A" weighted form. The sound
level meter and microphone were mounted on a tripod, five feet above the ground and
equipped with a windscreen during all measurements. The sound level meter was calibrated
before and after the monitoring using a Larson-Davi~ calibrator, Model CAL 200.
Monitoring location 1 {Mll) was located in the future location of Lot 7. The results of the noise
level measurements are presented in Table 4-1. The noise measurements were monitored for a
time period of 20 minutes during standard traffic conditions. The existing noise levels in the
project area consisted primarily of traffic from cannon Road and Faraday Avenue and aircraft
noise from McClellan-Palomar Airport. The ambient Leq noise levels measured in the area of
the Project during the morning hours was found to be roughly 56 dBA. The statistical indicators
Lmax, Lmin, LlO, LS0 and L90, are given for the monitoring location. As can be seen from the
L90 data, 90% of the time the noise level is approximately 42 dBA from the nearby roadways.
The lower noise levels are due to distance separation and the vertical off set between the
roadways and the Project site (the roadways are located over 100 feet below the site). The
noise monitoring locations are provided graphically in Figure 4-A on the following page.
Table 4-1: Measured Ambient Noise Levels
Measurement Noise Levels (dBA}
Identification Description Time
Leq Lmax Lmin L10 LSO L90
MLl Future Lot 7 10:25 a.m. -56.1 73.8 40.3 57.2 45.5 42.1 10:45 p.m.
Sol.rce: Lein Consulting, Inc. 5/20/15
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4.2 AirJX)rt Related Noise
To determine the airJX)rt related noise environment and impact JX)tentials the McClellan-
Palomar AirJX)rt Land Use Compatibility Plan (ALUCP) was compared to the project site location.
According to the ALUCP adopted March 4, 2010, the project site is located outside of the 60
dBA CNEL noise contours from the airJX)rt. Therefore, no mitigation related to airJX)rt noise is
required. The project site and future noise contours are provided graphically in Figure 4-2
below.
Figure 4-B: Palomar Airport Noise Contours
4.3 Future Noise Prediction Methodology
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The primary source of noise impacts to the project site will be background vehicular noise from
Cannon Road located over 2000 feet west of the project site and Faraday Avenue located over 600
feet west, south, and east of the project site. The projected roadway noise levels from vehicular
traffic were calculated using the methods in the Highway Noise Model published by the Federal
Highway Administration (FHWA Highway Traffic Noise Prediction Model, FHWA-RD-77-108,
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December, 1978). The FHWA Model uses the traffic volume, vehicle mix, speed, and roadway
geometry to compute the equivalent noise level. A spreadsheet calculation was used which
computes equivalent noise levels for each of the time pericx:ls used in the calculation of CNEL
Weighting these equivalent noise levels and summing them gives the CNEL for the traffic
projections.
Mobile noise levels radiant in an almost oblique fashion from the source and drop off at a rate
of 3 dBA for each doubling of distance under hard site conditions and at a rate of 4.5 dBA for
soft site conditions. Hard site conditions consist of concrete, asphalt and hard pack dirt while
soft site conditions exist in areas having slight grade changes, landscaped areas and vegetation.
Hard site conditions, to determine the worst-case findings, were used to develop and analyze the
noise levels along the roadway segments. The future traffic noise model utilizes a typical vehide
mix of 96% Autos, 2% Medium Trucks and 2% Heavy Trucks for both roadways. The vehicle mix
provides the hourly distribution percentages of automobile, medium trucks and heavy trucks for
input into the FHWA Model.
4.4 Rndings and Mitigation
Roadway Noise
cannon Road and Faraday Avenue are expected to have 24,600 ADT and 6,400 ADT, respectively,
according to the SANDAG Series 12 Traffic Prediction Model for the year 2035. The speed limit
along cannon Road is 50 MPH and 40 MPH on Faraday Avenue. Based on the exterior noise
model, the worst-case rumulative noise level from all the roadways was found to be 52.8 dBA
CNEL at the site. The modeling results are provided in Rgure 4 on the following page. No noise
barriers, existing structures or topography that may affect noise levels were incorporated in the
calculations.
Combined Aircraft: and Roadway Noise Levels
Based on the exterior noise model for the roadway the worst-case exterior noise level at the
building fac;ade of the site is 52.8 dBA CNEL. The airport related activities at the site is well below
60 dBA CNEL based on the McClellan-Palomar Airport Land Use Compatibility Plan (ALUCP) noise
contours. To be conservative, a worst case noise level of 56.1 dBA CNEL was utilized based on the
ambient noise measurements. The combination of the roadway and aircraft: activities was
combined to determine the overall rumulative noise levels at the building facades.
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Figure 4-C: Future Cumulative Noise Levels
Project Name: Oceanview Carlsbad Date: 26-May-15
Project Number: 15-72 Location: Carlsbad
I Traffic volumes, Mix a; s~s
Autos Med. Tru;seavyTrucks I
Mix Ratio by Percent 96.0 2.0 2.0
Propagation Rule Soft
Roadway ADT Speed MPH CNEL @ SO Feet 60 CNEL (Feet)
Faraday Avenue 6,400 40 66.2 129
cannon Road 24,600 50 74.2 442
I Noise Reduction clue to Distance I
Distance Reduction Resultant Level
Faraday Avenue 600 -16.19 50.0
Cannon Road 2,200 -24.65 49.5
Cumulative Noise Level 52.8 dBACNEL
Sound levels are logarithmic and so cannot be manipulated without being converted back to a
linear scale. You must first antilog each number, add or subtract and then log them again in the
following way:
Li 56.l 5:2.8
L = 10 * Log Lf 1010 or L = 10 * Log [1010 + 1010] = 57.8 dBA CNEL
Adding the two noise sources yields a cumulative future noise level of approximately 58 dBA CNEL
at the project site. Based upon these findings the future noise levels were found to be at or below
60 dBA CNEL and no noise mitigation is required to comply with the City of carlsbad Noise
standards. The building facades would also be below the 60 dBA CNEL. Therefore, no interior
mitigation is required.
Project Related Roadway Noise Levels
To determine if off-site noise level increases associated with the development of the proJX)sed
project would create noise impacts, the traffic volumes for the existing conditions and the traffic
volume increase of the proposed project were analyzed. The project is estimated to generate 130
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daily trips with a peak hour volume of 13 trips. The existing average daily traffic (ADT) volumes at
the project access point, within the cul-de-sac of Twain Avenue, has six homes with an estimated
peak volume of 6 ttips and a daily trip @te of 60 ADT. The combined existing plus project traffic
volumes would equate to an overall worst-case noise level of 49 dBA CNEL. This noise level is well
below the Oty's 60 dBA CNEL threshold and no project related traffic noise impacts would occur.
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Lein Consulting, Inc. 6/23/15 1572-03 Oceanview Carlsbad Noise Report