HomeMy WebLinkAboutSP 31A; Papagayo Development; Specific Plan (SP) (9)MESTRE GREVE ASSOCIATES
NOISE ASSESSMENT WINDSONG SHORES RESIDENTIAL PROJECT
CITY OF CARLSBAD
JUNE 1983
1.0 EXISTING NOISE ENVIRONMENT
1.1 Introduction
The proposed project calls for the development of a residential project
adjacent to the Agua Hedionda Lagoon in the City of Carlsbad. There are two
noise concerns related to this project. The first is the impact of traffic
associated with this project on adjacent residential areas. The second
concern is the impact of noise on the project. There are two sources of
noise, Interstate 5 on the east boundary of the project and the railroad on
the west boundary of the project.
This noise study will analyze the noise impact of the project on
adjacent land uses and will determine the ultimate noise levels that may
exist on the property. These levels will then be compared with applicable
City/State noise criteria and, if necessary, potential mitigation measures
will be suggested.
1.2 Noise Assessment Criteria
Several rating scales have been developed for measurement of community
noise. These account for:
* The parameters of noise that have been shown to contribute
to the effects of noise on man.
* The variety of noises found in the environment.
* The variations in noise levels
through the environment.
that occur as a person moves
* The variations associated with the time of day.
Predominant rating scales now in use in California for land use
compatibility assessment include the Equivalent Noise Level (LEQ) and the
Community Noise Equivalent Level (CNEL). Both scales are based on the
A-weighted decibel. A-weighting is a frequency correction that correlates
overall sound pressure levels with the frequency response of the human ear.
LEQ is the sound level corresponding to a steady state sound level containing
the same total energy as a time-varying signal over a given sample period.
LEQ is the "energy" average noise level.
CNEL is similar to LEQ but applies weighting factors which place greater
significance on noise events occurring during the night and evening hours.
-1-June 1983
CNEL is a 24-hour, time-weighted annual average noise level. Time-weighted
refers to the fact that noise that occurs during certain sensitive time
periods is penalized for occurring at these times. The evening time period
(7 p.m. to 10 p.m.) penalizes noise by 5 dBA, while nighttime (10 p.m. to 7
a.m.) noises are penalized by 10 dBA. These time periods and penalties were
selected to reflect people's sensitivity to noise as a function of activity.
The criterion used to assess the acceptability of community noise levels
can vary with the municipality. The City of Carlsbad adopted a Noise Element
in 1975 which included policies related to noise. This Noise Element did not
adopt specific noise standards for residential development. However, the
State of California has adopted Title 25 of the Uniform Building Code which
requires that the interior spaces of multi-family dwellings not be exposed to
noise levels in excess of 45 CNEL. Most counties and cities have adopted
exterior noise standards which apply to patio and yard areas of homes. The
most common standard for these areas is 65 CNEL. In the absence of any
Carlsbad standard for exterior areas, this 65 CNEL standard will be used here
for comparative purposes for exterior areas.
1.3 Existing Noise Levels
The existing noise levels were established by computer modeling the
roadways for the current traffic and speed characteristics. The existing
environment was modeled in order to establish a baseline noise level to which
the project and no-project noise levels can be compared.
Existing noise levels in the vicinity of the project were established in
terms of the CNEL index. The roadways that were modeled for existing
conditions include roadways adjacent to the project sites and those that will
be affected by project generated traffic.
The noise levels projected in this report were computed using the
Highway Noise Model published by the Federal Highway Administration ("FHWA
Highway Traffic Noise Prediction Model," FHWA-RD-77-108, December 1978). The
FHWA Model uses traffic volume, vehicle mix, vehicle speed, and roadway
geometry to compute the "equivalent noise level." A computer code has been
written which computes equivalent noise levels (LEQ) for each of the time
periods used in CNEL. Weighting these noise levels and summing them results
in the CNEL for the traffic projections used.
Traffic data used to project the existing noise level are shown in Table
1. These data are derived from the traffic study completed for this EIR.
The traffic mixes and time distributions are presented in Table 2. The
traffic mix data are based upon surveys conducted in Southern California and
are considered typical for arterials in this area. The freeway was assummed
to carry 6 percent trucks (based on truck counts by CALTRANS for 1-5).
Distances to the CNEL contours for these roadways are shown in Table 3.
These values represent the distance from the centerline of the road to the
contour value shown. Note that the values given in Table 3 do not take into
account the effect of any noise barriers or topography that may affect
ambient noise levels. The noise contours for the residential streets are
extremely small, not extending beyond the right of way for the roads. These
-2- June 1983
data are included solely for the purpose of comparison with the noise contour
locations for ultimate traffic levels including the project.
Railroad noise contours were computed by using "Assessment of Noise
Environments around Railroad Operations," prepared by Wyl e Laboratories in
1973. The noise modeling assumptions included 14 (7 each direction) Amtrak
trains and 8 freight trains. All Amtrak trains were assummed to occur during
daytime hours. The freights were split into 1 train during the evening and 4
trains at night (leaving the remaining 3 trains during the day). Table 4
presents the distances to the noise contours from the center of the tracks.
The existing noise contours for the freeway and the railroad are plotted
in Figure 1. Again, these contours do not include shielding due to
topographic effects.
Table 1
TRAFFIC DATA USED TO PROJECT
EXISTING NOISE LEVELS
ROADWAY ADT SPEED
Harbor
Bal dwi n
Layang Layang
Chinquapin:
* East of 1-5
* West of Jefferson
* East of Jefferson
Jefferson:
* South of Tamarack
* North of Chinquapin
* North of Tamarack
Tamarack:
* West of Jefferson
* East of Jefferson
Interstate 5
180
50
350
910
490
1260
1780
1000
3350
4810
5860
87000
25
25
25
25
25
25
25
25
25
35
25
55
-3- June 1983
FIGURE 1 EXISTING CNEL CONTOURS
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2.0 POTENTIAL NOISE IMPACTS
The potential noise impacts may be segregated into two categories; (1)
the project's impact on the surrounding land uses, and (2) the impact of
ultimate noise levels on the project site.
2.1 Impacts on Adjacent Land uses
An important part of a noise analysis is the identification of
noise-sensitive land uses that may be impacted by the proposed project. This
would include any residential properties^ schools, hospitals, or other
noise-sensitive land uses adjacent to the project or situated along roadways
that will carry project-generated traffic. This project could generate
traffic on several local streets which have existing homes including Harbor,
Baldwin, Layang Layang, Chinquapin, Jefferson, and Tamarack. The project
ingress and egress has been designed to prevent use of Harbor and Baldwin by
the project.
Two types of noise impacts on adjacent land uses may arise from the
project: (1) construction noise, and (2) project-related traffic may increase
noise levels on properties located along primary access routes. An
additional source, trash collection activities, is discussed in this report.
2.1.1 Construction Noise
Construction noise will occur as a result of the development of the
proposed project. Construction noise represents a short-term impact on
ambient noise levels. Noise generated by construction equipment and
construction activities can reach high levels. Construction equipment noise
comes under the control of the Environmental Protection Agency's Noise
Control Program (Part 204 of Title 40, Code of Federal Regulations). Figure
2 lists the noise characteristics of common construction equipment.
The existing residential uses on the north boundary of the property will
be exposed to audible noise levels from construction for short periods of
time. Most of the types of construction activities associated with this type
of construction do not generate high noise levels. Enforcement of the limits
on time of construction activity should minimize construction noise impacts
(see mitigation section for recommended limits on hours for construction).
2.1.2 Project Generated Traffic Noise
The impact of the project on adjacent residential land uses is assessed
by determining the noise levels on these roadways both with and without the
project. The difference in noise levels would be due to the increase in
project traffic. The increase in traffic noise due to the project will be
presented in two forms. The first is the actual increase in noise level in
decibels and the second is the increase in distance to the 65 CNEL noise
contour.
Table 5 summarizes existing and future traffic volumes and project
generated traffic. Also presented in Table 5 is the increase in noise level
for future conditions with and without the project. The greatest noise
-5- June 1983
Table 2
TRAFFIC DISTRIBUTION PER TIME OF DAY
IN PERCENT OF ADT
(Arterials Only)
PERCENT OF ADT
VEHICLE TYPE DAY EVENING NIGHT
Automobil e
Medium Truck
Heavy Truck
75.51
1.56
0.64
12.57
0.09
0.02
9.34
0.19
0.08
Table 3
CNEL NOISE LEVELS FOR EXISTING
TRAFFIC CONDITIONS
ROADWAY SEGMENT
DISTANCE TO CNEL CONTOUR
FROM ROADWAY CENTERLINE (FEET)
60-CNEL 65-CNEL 70-CNEL
Harbor
Baldwin
Layang Layang
Chi nquapin:
* East of 1-5
* West of Jefferson
* East of Jefferson
Jefferson:
* South of Tamarack
* North of Chinquapin
* North of Tamarack
Tamarack:
* West of Jefferson
* East of Jefferson
Interstate 5
4
2
6
11
7
14
17
12
26
57
38
1131
2
1
3
5
3
6
8
6
12
26
18
525
—
.
1
2
2
3
4
3
6
12
8
244
TABLE 4
DISTANCE TO CNEL CONTOURS FOR RAILROAD OPERATIONS
DISTANCE TO CONTOUR IN FEET FROM RAILROAD
60 CNEL 65 CNEL 70 CNEL
498 271 130
FIGURE 2
SOUND PRESSURE LEVELS FOR CONSTRUCTION EQUIPMENT
Type of Equipment
(1)
Levels, in Decibels,
(A-Weighted) Fast
(2)
Scrapers
Scrapers, elevating
Graders
Dozers
with squeaky tracks
Dozers, sheepsfoot
Rollers
Rollers, vibrating
Loaders, bucket
Loaders, terex
Backhoe
Gradall
Crane
Trucks, off highway
Trucks, asphalt
Trucks, concrete
Trucks, cement
Trucks, 14-wheel
Tractors, with water pump
Pavers
Autograder
Compressors
Rock drills (handheld, pneumatic)
(track mounted)
Concrete saws
Concrete saws, chain
Water pumps
Concrete pumps
Generators
Concrete plant
Asphalt plant
Pile driver (Vulcan No. 1)
89-95
88
77-87
87-89
90-93
82-88
72-80
80-85
80-81
96
79-91
87-88
80-85
81-96
69-82
71-82
91
88
73-80
82-92
81
71-87
88
91
87
88-93
79
76
69-75
93
91
90
increase will occur on Layang Layang where a 7.7 dB increase is projected.
However, only 2.2 dB of this increase is associated with the project.
Project generated noise increases on local streets range from 0 to 2.2 dB. A
3 dB change is the minimum change that is perceptable to the human ear.
Therefore, project generated noise increases are not considered significant.
Note that the access to the project has been specifically designed to keep
project traffic off of Harbor and Baldwin.
TABLE 5
INCREASE IN NOISE LEVELS DUE TO PROJECT GENERATED TRAFFIC
STREET
ACCESS 1
HARBOR
BALDWIN
LAYANG LAYANG
CHINQUAPIN:
* EAST OF 1-5
* WEST OF JEFFERSON
* EAST OF JEFFERSON
JEFFERSON:
* SOUTH OF TAMARACK
* NORTH OF CHINQUAPIN
* NORTH OF TAMARACK
TAMARACK:
* WEST OF JEFFERSON
* EAST OF JEFFERSON
1-5
CHANGE IN ULTIMATE NOISE
(DECIBELS)
EXISTING PROJECT ULTIMATE WITH WITHOUT DUE TO
ADT ADT ADT PROJECT PROJECT PROJECT
0
180
50
350
910
490
1260
1780
1000
3350
4810
5860
87000
380
0
0
820
300
380
710
900
900
300
240
360
1200
720
180
50
2080
1520
1210
2740
3620
2840
3965
5300
6595
107000
_
0.00
0.00
7.74
'
2.23
3.93
3.37
3.08
4.53
0.73
0.42
0.51
0.90
_
0.00
0.00
5.56
1.27
2.29
2.07
1.84
2.88
0.39
0.22
0.27
0.85
_
0.00
0.00
2.18
0.95
1.64
1.30
1.24
1.66
0.34
0.20
0.24
0.05
CNEL contour locations have been computed for ultimate traffic
conditions. These have been computed for both with and without the project
conditions. Table 6 presents the CNEL contour locations for ultimate
conditions without the project and Table 7 presents CNEL contour locations
for ultimate conditions with the project. As can easliy be seen in these
tables the distances to the 65 CNEL contours do not change significantly as a
result of the project.
-6-June 1983
TABLE 6
CNEL CONTOURS FOR ULTIMATE CONDITIONS WITHOUT THE PROJECT
ROADWAY
Access 1
Harbor
Baldwin
Layang Layang
Chinquapin:
* East of 1-5
* West of Jefferson
* East of Jefferson
Jefferson:
* South of Tamarack
* North of Chinquapin
* North of Tamarack
Tamarack:
* West of Jefferson
* East of Jefferson
Interstate 5
DISTANCE
60 CNEL
6
4
2
14
13
10
19
,
23
18
28
59
40
1289
TO CONTOUR
65 CNEL
3
2
1
6
6
5
9
11
9
13
27
19
598
(feet)
70 CNEL
' 1
1
.
3
3
2
4
5
4
6
13
9
278
TABLE 7
CNEL CONTOURS FOR ULTIMATE CONDITIONS WITH THE PROJECT
ROADWAY
Access 1
Harbor
Bal dwin
Layang Layang
Chinquapin:
* East of 1-5
* West of Jefferson
* East of Jefferson
Jefferson:
* South of Tamarack
* North of Chinquapin
* North of Tamarack
Tamarack:
* West of Jefferson
* East of Jefferson
Interstate 5
DISTANCE
60 CNEL
10
4
2
19
16
13
23
28
24
30
61
42
1298
TO CONTOUR
65 CNEL
4
2
1
9
7
6
11
13
11
14
28
19
602
(feet)
70 CNEL
2
1
-4
3
3
5
6
5
6
13
9
279
-7-June 1983
2.1.3 Trash Collection Activities
Trash collection from this site will generate noise. Trash trucks
accessing the site will make noise audible to neighbors. Each unit of the
project is furnished with a trash compactor. In addition, trash is collected
in each building and further compacted. This trash is then placed in bins
identified on the site plan for collection and transported for disposal. Two
bins are near existing residential units.
2.2 Impact of Noise Levels on the Project
2.2.1 Exterior Noise Levels
The noise levels projected in the existing environment section
determined that the railroad and the freeway are the dominate noise sources
on the property. Figure 3 presents the CNEL contours on the site for
ultimate traffic conditions (including the project). These contours do not
include shielding effects due topographic effects. The topograhic effects
are not included here because it would be a very complex matter to estimate
accurately the barrier effects afforded by the topography. Units adjacent to
the freeway are not shielded at all and have a direct line of sight with the
freeway. Units located back from the bluff are shielded from the freeway but
may have a line of sight with the freeway from the direction of the lagoon.
Buildings on the site may also shield other buildings. If a location has no
line of sight with the freeway, 5 to 15 dB noise reduction may occur. If a
portion of the freeway is visible then the barrier effects are significantly
reduced. For example, if line of sight with the freeway is blocked for 90
degrees, but the other 90 degrees is visible the maximum noise reduction
achievable is 3 dB.
As can be seen in Figure 3 the noise contours for both the railroad and
the freeway extend onto the project site. The units closest to the freeway
may be exposed to exterior noise levels of approximately 74 CNEL and units
closest to the railroad may be exposed to noise levels of 69 CNEL. These
levels are above typical exterior noise standards. Exterior noise standards
typically apply only to private outdoor living areas such as private yards
and patios. For this project there are no private yards only private patios
and balconies. Mitigation of these patios and balconies is discussed in the
mitigation section of this report.
2.2.2 Interior Noise Levels
The State of California requires that the interior noise levels for
multi-family residential units not exceed 45 CNEL due to exterior noise
sources.
From the site plan for the project the closest unit is 159 feet from the
centerline of the freeway and the closest unit to the railroad is 150 feet
away. The maximum freeway exposure is 74 CNEL and and the maximum railroad
exposure is 69 CNEL. Therefore, a 29 dBA indoor/outdoor building attenuation
will be needed to meet the interior noise level criterion. This required
June 1983
FIGURE 3 ULTIMATE CNEL CONTOURS
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building attenuation can be achieved with normal building construction, if
designed properly. Prior to issuance of building permits the architectural
design of the buildings should be reviewed to determine if adequate
outdoor/indoor noise reductions are achieved.
3.0 MITIGATION MEASURES
3.1 Construction
Construction noise can best be mitigated through the limiting of hours
for construction. The City of Carlsbad has done this in the past as part of
the Conditions of Approval. Limiting hours of construction to 7 am to sunset
on weekdays, and 8 am to sunset on Saturdays and no construction on Sundays
should minimize construction noise impacts.
3.2 Exterior
Exterior noise levels for units adjacent to the freeway and the railroad
will exceed 65 CNEL. Private patios and balconies on certain units that face
these noise sources could be provided with noise mitigation in the form of a
patio noise barrier. This noise barrier could be any solid structure with no
holes or cracks having a surface density of 4 pounds per square foot or
greater. The barrier should completely shield all line of sight with the
noise source and have a top elevation 6 feet above the finished floor
elevation of the patio. If views are to be preserved a glass panel (1/4 inch
tempered) can serve as the top portion of the barrier. There are no state
laws or City policies which mandate these barriers. This alternative is
discussed only for information purposes.
3.3 Interior
Since the architectural plans have not been finalized for this site, the
indoor/outdoor noise reduction for the buildings in the project cannot be
determined. Based upon the preliminary plans, the outdoor/indoor noise
reduction requirements are 29 dBA. This building attenuation requirement can
be achieved for buildings that are located adjacent to major noise sources
such as with this project. At the time of building permit application, the
architectural plans must be reviewed to ensure compliance with the State of
California interior noise standard. The State requires demonstration of
compliance when the exterior noise environment is greater than 60 CNEL. At
that time, any additional measures (thicker glazing, sound absorption
material, or shielding of vents) to further attenuate the noise to acceptable
levels can be specified.
SPECIAL SECTION - THE BULLET TRAIN
The "bullet train" has been proposed near this site. The project
proponents have not presented any specific and reliable information
concerning the bullet train noise. As part of any project to construct the
-9- June 1983
bullet train system, noise would have to considered as part of that process.
Insufficient information is available now to assess the noise impacts of the
bullet train.
CONTACTS
The following people were contacted for information:
Larry Hunts
Mike Howes
Lynette Cervantes
Tom Miner
Ray Moe