3.9 Noise and Vibration

Transcription

1 Introduction This section describes the potential noise and vibration impacts of the Proposed Project. It includes a discussion of existing regulatory requirements, the existing noise setting within the project area, and noise and vibration impacts that would result from implementation of the Proposed Project. Supporting technical information and analyses are hereby incorporated by reference and included as Appendix I [Noise Modeling Calculations] of this Environmental Impact Report (EIR). As noted in the analysis below, impacts related to noise and vibration during construction activities would be significant and unavoidable, despite the application of mitigation measures. During operation, impacts would also be significant. However, with incorporation of required mitigation measures, noise impacts during operation would result in less than significant impacts Noise Fundamentals Noise is commonly defined as unwanted sound. Sound can be described as the mechanical energy of a vibrating object transmitted by pressure waves through a liquid or gaseous medium (e.g., air) to a hearing organ, such as a human ear. Noise is often defined as sound that is objectionable because it is disturbing or annoying. In the science of acoustics, the fundamental model consists of a sound (or noise) source, a receptor, and the propagation path between the two. The loudness of the noise source and the obstructions or atmospheric factors, which affect the propagation path to the receptor, determine the sound level and the characteristics of the noise perceived by the receptor. Continuous sound can be described by frequency (pitch) and amplitude (loudness). A low- frequency sound is perceived as low in pitch; a high- frequency sound is perceived as high- pitched. Frequency is expressed in terms of cycles per second, or Hertz (Hz) (e.g., a frequency of 250 cycles per second is referred to as 250 Hz). High frequencies are sometimes more conveniently expressed in kilohertz (khz), or thousands of Hz. The audible frequency range for humans is generally between 20 Hz and 20,000 Hz. Very- low- frequency airborne sound of sufficient amplitude may be felt before it can be heard, and can be confused with ground- borne vibration. The amplitude of pressure waves generated by a sound source determines the loudness of that source. As discussed in further detail below, the sound pressure level (also referred to simply as the sound level) is typically described in terms of decibels. Decibels The magnitude of a sound is typically described in terms of sound pressure level (SPL), which refers to the root- mean- square pressure of a sound wave and is measured in units called micropascals (µpa). One μpa is approximately one hundred- billionth ( ) of normal atmospheric pressure. Sound pressure amplitudes for different kinds of noise environments can range from less than 100 to over 100,000,000 μpa. Because of this large range of values, sound is rarely expressed in terms of μpa. Instead, a logarithmic scale is used to describe the sound pressure level in terms of 3.9-1

2 decibels, abbreviated db. The decibel is a logarithmic unit that describes the ratio of the actual sound pressure to a reference pressure (20 µpa is the standard reference pressure level for acoustical measurements in air). Specifically, a sound pressure level, in decibels, is calculated as follows: SPL = 20 log10 20µ X Pa where X is the actual sound pressure and 20 µpa is the reference pressure. The threshold of hearing for young people is about 0 db, which corresponds to 20 μpa. Decibel Addition Because decibels are logarithmic units, sound pressure levels cannot be added or subtracted through ordinary arithmetic. On the db scale, a doubling of sound energy corresponds to a 3- db increase. In other words, when two identical sources are each producing the same sound level, their combined sound level would be 3 db higher than one source under the same conditions. For example, if one bulldozer produces a sound pressure level of 80 A- weighted decibels (dba), two bulldozers would not produce 160 dba; rather, they would combine to produce 83 dba. The cumulative sound level of any number of sources, such as excavators, can be determined using decibel addition. A- Weighting The db scale alone does not adequately characterize how humans perceive noise. The dominant frequencies of a sound have a substantial effect on the human response to that sound. Although the intensity (energy per unit area) of the sound is a purely physical quantity, the loudness or human response is determined by characteristics of the human ear. Human hearing is limited in the range of audible frequencies as well as in the way it perceives the sound pressure level in that range. In general, people are most sensitive to the frequency range of 1,000 to 8,000 Hz and perceive sounds within that range better than sounds of the same amplitude in higher or lower frequencies. To approximate the response of the human ear, sound levels of individual frequency bands are weighted (i.e., adjusted), depending on human sensitivity to those frequencies. The resulting sound pressure level is expressed in A- weighted decibels or dba. The A- weighting scale approximates the frequency response of the average young ear when listening to most ordinary sounds. When people make judgments regarding the relative loudness or annoyance of a sound, their judgments correlate well with the A- weighted sound levels of those sounds. Table describes typical A- weighted sound levels for various noise sources

3 Table Typical A- Weighted Sound Levels Common Outdoor Noise Source Sound Level (dba) Common Indoor Noise Source 110 Rock band Jet flying at 1,000 feet 100 Gas lawn mower at 3 feet 90 Diesel truck at 50 feet at 50 mph Food blender at 3 feet 80 Garbage disposal at 3 feet Noisy urban area, daytime Gas lawn mower at 100 feet 70 Vacuum cleaner at 10 feet Commercial area Normal speech at 3 feet Heavy traffic at 300 feet 60 Large business office Quiet urban daytime 50 Dishwasher in next room Quiet urban nighttime 40 Theater, large conference room (background) Quiet suburban nighttime Quiet rural nighttime 30 Library Bedroom at night Broadcast/recording studio Lowest threshold of human hearing 0 Lowest threshold of human hearing Source: California Department of Transportation, 2013a. Noise Descriptors Because sound levels can vary markedly over a short period of time, a method for describing either the average character of the sound or the statistical behavior of the variations is utilized. Most commonly, environmental sounds are described in terms of the average level, or equivalent sound level (abbreviated ), that describes the average acoustical energy content of noise for an identified period of time. Thus, the of a time- varying noise and that of a steady noise are the same if they deliver the same acoustical energy over the duration of the exposure. A common averaging period is hourly, but can describe any series of noise events of arbitrary duration. The scientific instrument used to measure noise is the sound level meter. Sound level meters can accurately measure environmental noise levels to within approximately plus or minus 1 dba. Additional commonly used noise metrics are described in Table below, along with a summary of definitions of technical acoustical terms used in this section. Two of the metrics, Day/Night Noise Level (L dn) and Community Noise Equivalent Level (), describe 24- hour average noise levels. When measured in typical outdoor environments, and L dn are normally within 1 dba of each other

4 Table Definitions of Acoustical Terms Term Decibel (db) Sound Pressure Level Frequency (Hz) A- Weighted Sound Level (dba) Equivalent Sound Level () Community Noise Equivalent Level () Day/Night Noise Level (L dn) Percentile- Exceeded Sound Level (L XX) Maximum Sound Level (L max) Minimum Sound Level (L min) Ambient Noise Level Source: ICF International, Definition A unit describing the amplitude of sound equal to 20 times the logarithm to base 10 of the ratio of the pressure of the sound measured to the reference pressure. The reference pressure for air is 20 μpa. Sound pressure is the sound force per unit area, usually expressed in μpa (or micronewtons per square meter), where 1 pascal is the pressure resulting from a force of 1 newton exerted over an area of 1 square meter. The sound pressure level is expressed in decibels as 20 times the logarithm to base 10 of the ratio between the pressures exerted by the sound to a reference sound pressure (e.g., 20 μpa in air). Sound pressure level is the quantity that is measured directly by a sound level meter. The number of complete pressure fluctuations per second above and below atmospheric pressure. Normal human hearing is between 20 Hz and 20,000 Hz. Infrasonic sounds are below 20 Hz, and ultrasonic sounds are above 20,000 Hz. The sound pressure level in decibels as measured on a sound level meter using the A weighting filter network. The A- weighting filter de- emphasizes the very low- and very high- frequency components of the sound in a manner similar to the frequency response of the human ear and correlates well with subjective reactions to noise. The average A- weighted noise level during the measurement period. The hourly used for this report is denoted as dba (h). The average A- weighted noise level during a 24- hour day, which is obtained by adding 5 db to sound levels in the evening from 7 p.m. to 10 p.m., and 10 db to sound levels between 10 p.m. and 7 a.m. The average A- weighted noise level during a 24- hour day, which is obtained by adding 10 db to sound levels measured at night between 10 p.m. and 7 a.m. The A- weighted noise level that is exceeded XX% of the time during the measurement period. E.g., L 25 is the sound level exceeded 25% of the time, and L 50 is the sound level exceeded 50% of the time. The maximum sound level measured during the measurement period. The minimum sound level measured during the measurement period. The composite of noise from all sources near and far. The normal or existing level of environmental noise at a given location. Human Response to Noise Studies have shown that under controlled conditions in an acoustics laboratory, a healthy human ear is able to discern changes in sound levels of 1 dba. In the normal environment, the healthy human ear can detect changes of about 2 dba; however, it is widely accepted that changes of 3 dba in the normal environment are considered just noticeable to most people. A change of 5 dba is readily perceptible, and a change of 10 dba is perceived as being twice as loud. Accordingly, a doubling of sound energy (e.g., doubling the volume of traffic on a highway) resulting in a 3- db increase in sound would generally be barely detectable

5 Sound Propagation When sound propagates over a distance, it changes in both level and frequency content. The manner in which noise is reduced with distance depends on the following important factors. l l l l Geometric Spreading. Sound from a single source (i.e., a point source) radiates uniformly outward as it travels away from the source in a spherical pattern. The sound level attenuates (or drops off) at a rate of 6 dba for each doubling of distance. Highway noise is not a single stationary point source of sound. The movement of vehicles on a highway makes the source of the sound appear to emanate from a line (i.e., a line source) rather than from a point. This results in cylindrical spreading rather than the spherical spreading resulting from a point source. The change in sound level (i.e., attenuation or decrease) from a line source is 3 dba per doubling of distance. Ground Absorption. Usually the noise path between the source and the observer is very close to the ground. The excess noise attenuation from ground absorption occurs due to acoustic energy losses on sound wave reflection. Traditionally, the excess attenuation has also been expressed in terms of attenuation per doubling of distance. This approximation is done for simplification only; for distances of less than 200 feet, prediction results based on this scheme are sufficiently accurate. For acoustically hard sites (i.e., sites with a reflective surface, such as a parking lot or a smooth body of water, between the source and the receptor), no excess ground attenuation is assumed because the sound wave is reflected without energy losses. For acoustically absorptive or soft sites (i.e., sites with an absorptive ground surface, such as soft dirt, grass, or scattered bushes and trees), an excess ground attenuation value of 1.5 dba per doubling of distance is normally assumed. When added to the geometric spreading, the excess ground attenuation results in an overall drop- off rate of 4.5 dba per doubling of distance for a line source and 7.5 dba per doubling of distance for a point source. Atmospheric Effects. Research by the California Department of Transportation (Caltrans) and others has shown that atmospheric conditions can have a major effect on noise levels. Wind has been shown to be the single most important meteorological factor within approximately 500 feet, whereas vertical air temperature gradients are more important over longer distances. Other factors, such as air temperature, humidity, and turbulence, also have major effects. Receptors downwind from a source can be exposed to increased noise levels relative to calm conditions, whereas receptors upwind can have lower noise levels. Increased sound levels can also occur because of temperature inversion conditions (i.e., increasing temperature with elevation, with cooler air near the surface, where the sound source tends to be and the warmer air above acts as a cap, causing a reflection of ground level generated sound). Shielding by Natural or Human- Made Features. A large object or barrier in the path between a noise source and a receptor can substantially attenuate noise levels at the receptor. The amount of attenuation provided by this shielding depends on the size of the object, proximity to the noise source and receptor, surface weight, solidity, and the frequency content of the noise source. Natural terrain features (such as hills and dense woods) and human- made features (such as buildings and walls) can substantially reduce noise levels. Walls are often constructed between a source and a receptor with the specific purpose of reducing noise. A barrier that breaks the line of sight between a source and a receptor will typically result in at least 5 db of noise reduction. A higher barrier may provide as much as 20 db of noise reduction

6 Ground- borne Vibration Fundamentals Ground- borne vibration is an oscillatory motion of the soil with respect to the equilibrium position and can be quantified in terms of velocity or acceleration. The velocity describes the instantaneous speed of the motion and acceleration is the instantaneous rate of change of the speed. Each of these measures can be further described in terms of frequency and amplitude. Typical outdoor sources of perceptible ground- borne vibration are heavy construction equipment (such as blasting and pile driving), railroad operations, and heavy trucks on rough roads. If a roadway is smooth, the ground- borne vibration from traffic is rarely perceptible. Ground- borne vibration can be a serious concern for neighbors of nearby sources, causing buildings to shake and rumbling sounds to be heard. Most perceptible indoor vibration is caused by sources within buildings, such as the operation of mechanical equipment, movement of people, or the slamming of doors. Ground- borne vibration can be described in terms of peak particle velocity (PPV). PPV is defined as the maximum instantaneous positive or negative peak amplitude of the vibration velocity. The unit of measurement for PPV is inches per second (in/s). For transient vibration sources (single isolated vibration events such as blasting), the human response to vibration varies from barely perceptible at a PPV of 0.04 in/s, to distinctly perceptible at a PPV of 0.25 in/s, and severe at a PPV of 2.0 in/s. For continuous or frequent intermittent vibration sources (such as impact pile driving or vibratory compaction equipment), the human response to vibration varies from barely perceptible at a PPV of 0.01 in/s, to distinctly perceptible at a PPV of 0.04 in/s, and severe at a PPV of 0.4 in/s (California Department of Transportation 2013b). If a person is engaged in any type of physical activity, vibration tolerance increases considerably Regulatory Setting State Regulations California requires each local government entity to perform noise studies and implement a noise element as part of its general plan. The purpose of the noise element is to limit the exposure of the community to excessive noise levels; the noise element must be used to guide decisions concerning land use. The state provides guidelines for evaluating the compatibility of various land uses as a function of community noise exposure Local L.A. CEQA Thresholds Guide The L.A. CEQA Thresholds Guide (City of Los Angeles 2006) defines noise- sensitive land uses as residences, transient lodgings, schools, day- care facilities, libraries, churches, hospitals, nursing homes, auditoriums, concert halls, amphitheaters, playgrounds, and parks, and provides noise/land use compatibility guidelines, as summarized in Table

7 Table Land Use Noise Compatibility Guidelines Land Use Single- Family, Duplex, Mobile Homes Normally Acceptable Community Noise Exposure, db Conditionally Acceptable Normally Unacceptable Clearly Unacceptable above 70 Multifamily Homes above 70 Schools, Libraries, Churches, Hospitals, Nursing Homes Transient Lodging Motels, Hotels Auditoriums, Concert Halls, Amphitheaters Sports Arena, Outdoor Spectator Sports Playgrounds, Neighborhoods Parks Golf Courses, Riding Stables, Water, Recreation, Cemeteries above above above above above above 80 Normally Acceptable: Specified land use is satisfactory, based on the assumption that any buildings involved are of normal conventional construction and without any special noise insulation requirements. Conditionally Acceptable: New construction or development should be undertaken only after a detailed analysis of the noise reduction requirements is made and needed noise insulation features included in the design. Conventional construction, but with closed windows and fresh air supply systems or air- conditioning, will normally suffice. Normally Unacceptable: New construction or development generally should be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements must be made and needed noise insulation features included in the design. Clearly Unacceptable: New construction or development generally should not be undertaken. Source: City of Los Angeles, City of Los Angeles Municipal Code Construction Noise Section 41.40(a) of the City of Los Angeles Municipal Code prohibits the use, operation, repair, or servicing of construction equipment, as well as job- site delivery of construction materials, between the hours of 9:00 p.m. and 7:00 a.m. where such activities would disturb persons occupying sleeping quarters in any dwelling hotel or apartment or other place of residence. Construction noise emanating from property zoned for manufacturing or industrial uses is exempted from the Section 41.40(a) standards. In addition, Section 41.40(c) prohibits construction, grading, and related job- site deliveries on or within 500 feet of land developed with residential structures before 8:00 a.m. or after 6:00 p.m. on any Saturday or national holiday or at any time on Sunday. Section of the municipal code places limits on the maximum noise levels (75 dba at a distance of 50 feet for typical construction equipment) that may be produced by powered equipment or tools in, or within 500 feet of, any residential zone between the hours of 7 a.m. and 10 p.m. The proscribed limits shall not apply where compliance is technically infeasible but the 3.9-7

8 burden of proving that compliance is technically infeasible is on the person or persons charged with a violation of the standard. Technical infeasibility shall mean that the noise limit cannot be complied with despite the use of mufflers, shields, sound barriers, and/or other noise reduction devices or techniques during the operation of the equipment. Operational Noise Chapter XI, Noise Regulation, of the City of Los Angeles Municipal Code regulates noise from non- transportation noise sources such as commercial or industrial operations, mechanical equipment, or residential activities. It is noted that while these regulations do not apply to vehicles operating on public rights- of- way, they do apply to noise generated by vehicles on private property such as truck operations at commercial or industrial facilities. The exact noise standards vary depending on the type of noise source, but the allowable noise levels are generally determined relative to the existing ambient noise levels at the affected location. Section (a) defines the ambient noise as the composite of noise from all sources near and far in a given environment, exclusive of occasional and transient intrusive noise sources and of the particular noise source or sources to be measured. Ambient noise shall be averaged over a period of at least 15 minutes Section provides minimum ambient noise levels for various land uses, as described in Table 3.9-4, below. In the event that the actual measured ambient level at the subject location is lower than that provided in the table, the level in the table shall be assumed. Table City of Los Angeles Assumed Minimum Ambient Noise Levels Zone Assumed Minimum Ambient Noise (), dba Daytime (7 a.m. 10 p.m.) Nighttime (10 p.m. 7 a.m.) A1, A2, RA, RE, RS, RD, RW1, RW2, R1, R2, R3, R4, and R P, PB, CR, C1, C1.5, C2, C4, C5, and CM M1, MR1, and MR M2 and M Source: City of Los Angeles, At the boundary line between two zones, the allowable noise level of the quieter zone shall be used. The allowable noise levels are then adjusted if certain conditions apply to the alleged offensive noise, as follows. l l l For steady tone noise with an audible fundamental frequency or overtones (except for noise emanating from any electrical transformer or gas metering and pressure control equipment existing and installed prior to September 8, 1986) reduce allowable noise level by 5 dba. For repeated impulsive noise reduce allowable noise level by 5 dba. For noise occurring less than 15 minutes in any period of 60 consecutive minutes between the hours of 7:00 a.m. and 10:00 p.m. increase allowable noise level by 5 dba. The City s noise ordinance is not explicit in defining the length of time over which an average noise level should be assessed. However, based on the noted reference to 60 consecutive minutes, above, it is inferred that the 1- hour metric should be used

9 Section of Chapter XI addresses noise from air conditioning, refrigeration, heating, pumping, and filtering equipment. It states that such equipment may not generate noise that would exceed the ambient noise level at any adjacent property by more than 5 dba. Section of Chapter XI addresses noise from motor driven vehicles (it is noted that the code only addresses vehicles on private property and does not address vehicles while operated on public highways). It states that such vehicles may not generate noise that would exceed the ambient noise level at any occupied residential property by more than 5 dba. City of Los Angeles Noise Element The Noise Element of the City s General Plan defines the following land uses to be noise- sensitive: single- and multi- family dwellings, long- term care facilities (including convalescent and retirement facilities), dormitories, motels, hotels, transient lodgings and other residential uses; houses of worship; hospitals; libraries; schools; auditoriums; concert halls; outdoor theaters; nature and wildlife preserves; and parks. The Noise Element contains the following polices that are relevant to the Proposed Project. Policy 5 Continue to enforce, as applicable, City, state and federal regulations intended to abate or eliminate disturbances of the peace and other intrusive noise. Policy 6 When processing building permits, continue to require appropriate project design and/or insulation measures, in accordance with the California Noise Insulation Standards (Building Code Title 24, Section 3501 et seq.), or any amendments thereto or subsequent related regulations, so as to assure that interior noise levels will not exceed the minimum ambient noise levels, as set forth in the City s noise ordinance ([Los Angeles Municipal Code] Section 111 et seq., and any other insulation related code standards or requirements) for a particular zone or noise- sensitive use, as defined by the California Noise Insulation Standards. Policy 11 For a proposed development project that is deemed to have a potentially significant noise impact on noise- sensitive uses, as defined by this chapter, require mitigation measures, as appropriate, in accordance with California Environmental Quality Act and City procedures. Policy 12 When issuing discretionary permits for a proposed noise- sensitive use (as defined by this chapter) or a subdivision of four or more detached single- family units and which use is determined to be potentially significantly impacted by existing or proposed noise sources, require mitigation measures, as appropriate, in accordance with procedures set forth in the California Environmental Quality Act Environmental Setting Existing Noise Environment The primary existing noise sources in the project area are traffic on local streets, occasional aircraft overflights, and general neighborhood activities such as landscaping and home improvements. Noise from the existing Venice Pumping Plant (VPP) is also audible at the closest homes to that facility, which are approximately 50 to 80 feet to the west and south, on Hurricane Street and Canal Court

10 The closest noise- sensitive receptors to the Project Site are residences (multi- and single- family) within approximately 15 feet of the Site. To the northwest, the Project Site is bounded by a neighboring residence. To the northeast, the site is bounded by a pedestrian/bike path and the Grand Canal, beyond which are existing homes along the east bank of the canal. To the southeast, the site is bounded by Hurricane Street, beyond which is the existing VPP; farther to the southeast are the Ballona Lagoon and more residences. To the southwest, the Project Site is bounded by Canal Court, beyond which are residences. Figure 2-2 (Chapter 2, Project Description) shows the Project Site and surrounding area. Noise Monitoring In order to determine the existing noise environment, measurements were obtained at five locations in the vicinity of the Project Site, as shown in Figure One long- term (approximately 4 days) noise measurement (LT- 1) was obtained at the northwest fence line of the Project Site. Short- term (ST) noise measurements (approximately 15 to 20 minutes) were obtained at four locations in the surrounding community. ST- 1 was located approximately 70 feet northeast of the Project Site, across the Grand Canal; ST- 2 was located approximately 20 feet southwest of the Project Site, across Canal Street; ST- 3 was located approximately 100 feet south of the Project Site, across the intersection of Canal Street and Hurricane Street; and ST- 4 was located approximately 400 feet southeast of the Project Site, across the Ballona Lagoon. The summary of the measurement results are provided in Tables and The long- term measurement was obtained between approximately 1:00 p.m. on Thursday, August 20, and 12:00 a.m. on Tuesday August 25, Short- term measurements were gathered on Thursday, August 20, and Tuesday August 25, In addition to the noise measurements obtained directly for this noise analysis, ambient noise data were also supplied by the Proposed Project s design engineer (Arcadis 2015); the memo discussing these noise measurements is included in Appendix I. These data were gathered on Thursday, April 23, 2015, at locations very close to four of the measurement locations shown in Figure and have also been added to Tables and The 24- hour noise levels for the locations monitored ranged from approximately 53 to 57 ; daytime hourly average (one hour ) noise levels ranged from approximately 45 to 66 dba according to the long- term measurements, evening average noise levels ranged from approximately 47 to 52 dba ; and nighttime hourly average noise levels ranged from approximately 40 to 52 dba. The values recorded during the short- term measurements ranged from approximately 50 to 53 dba for ST- 1, 48 to 50 dba for ST- 2, and 49 to 50 dba for ST- 3. The average noise level for ST- 4 was approximately 51 dba

11 K:\Irvine\GIS\Projects\LABOE\00476_15\mapdoc\Noise\Fig_3_9_1_Noise_Monitoring_Locations.mxd Date: 10/5/ Legend Long-Term Measurement Location Short-Term Measurement Location Project Site Feet Imagery Source: Microsoft Bing Aerial (2016) ± Figure Noise Monitoring Locations Project

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13 Table Summary of Long- Term Noise Measurements Location #, Description Date Time Period LT- 1, Adjacent to northwest fence line of Project Site, near north corner of site. Notes: Thursday 8/20/15 Friday 8/21/15 Saturday 8/22/15 Sunday 8/23/15 Monday 8/24/15 Thursday 4/23/15 b Range of Hourly Average Levels, Leq (1h), dba (average) Range of Hourly Minimum Levels, Lmin, dba Range of Hourly Maximum Levels, Lmax, dba 56.5 a Daytime (1 p.m. to 7 p.m.) (54.3) Evening (7 p.m. to 10 p.m.) (50.9) Nighttime (7 p.m. to 12 a.m.) (50.2) Daytime (7 a.m. to 7 p.m.) (56.3) Evening (7 p.m. to 10 p.m.) (49.1) Nighttime (12 a.m. to 7 a.m., and 7 p.m. to 12 a.m.) (45.6) Daytime (7 a.m. to 7 p.m.) (50.7) Evening (7 p.m. to 10 p.m.) (48.6) Nighttime (12 a.m. to 7 a.m., and 7 p.m. to 12 a.m.) (46.8) Daytime (7 a.m. to 7 p.m.) (50.2) Evening (7 p.m. to 10 p.m.) (48.4) Nighttime (12 a.m. to 7 a.m., and 7 p.m. to 12 a.m.) (44.8) Daytime (7 a.m. to 7 p.m.) (51.4) Evening (7 p.m. to 10 p.m.) (47.8) Nighttime (12 a.m. to 7 a.m., and 7 p.m. to 12 a.m.) (45.2) N/A Daytime (3:57 p.m. to 4:39 p.m.) a estimated by comparing available measured data from 8/20/15 with corresponding data and for days on which full 24- hour measurements were obtained (i.e., 8/21 through 8/24, 2015) b Supplemental data calculated from raw data included in the Arcadis memo (Arcadis 2015) (see Appendix I of this EIR). Sources: ICF International, 2015; Arcadis,

14 Table Summary of Short- Term Noise Measurements Location #, Description (Date, Time) ST- 1, northeast of Project Site, across Grand Canal, adjacent to 3815 Via Dolce ST- 2, southwest of Project Site, across Canal Court, in front of 129 Hurricane Street ST- 3, southwest of Project Site on Hurricane Street, in front of 120 Hurricane Street ST- 4, southeast of Project Site, across Ballona Lagoon, on trail adjacent to 107 Roma Court Notes: Estimated a 57 8/20/15, 2:12 p.m. 2:28 p.m. Measured Noise Levels, dba Date, Time Leq Lmin Lmax 8/25/15, 1:00 p.m. 1:19 p.m. 4/23/2015, 4:50 p.m. 5:20 p.m. b 56 8/20/15, 1:24 p.m. 1:44 p.m Average /25/15, 2:24 p.m. 2:45 p.m. 4/23/2015, 4:43 p.m. 5:13 p.m. b 56 8/20/15, 1:24 p.m. 1:42 p.m Average /25/15, 1:45 p.m. 2:19 p.m. 4/23/2015, 4:11 p.m. 4:41 p.m. b 57 8/20/15, 2:08 p.m. 2:24 p.m Average Average a estimated by comparing available measured data from 8/20/15 with corresponding data and for days on which full 24- hour measurements were obtained (i.e., 8/21 through 8/24, 2015) b Supplemental data calculated from raw data included in the Arcadis memo (Arcadis 2015) (see Appendix I of this EIR). Sources: ICF International, 2015; Arcadis,

15 3.9.4 Environmental Impact Analysis This section describes the methodology, evaluation, and impacts for temporary construction and permanent operational noise and vibration. This discussion is intended to assist in the evaluation and conclusions of the impact analysis provided below and in the formation of required mitigation measures Methodology Noise Measurements The long- term noise measurement of existing ambient noise levels was obtained using a Rion NL- 21 Type 2 sound level meter. The short- term noise measurements of existing ambient noise levels and VPP equipment noise levels were obtained using Larson Davis 831 and LxT Type 1 sound level meters. The sound level meters were field calibrated for accuracy using a Larson Davis CAL200 acoustical calibrator. Two measurements were obtained of equipment (pumps and motors) noise levels inside the existing VPP building, which is located southeast of the Project Site. The first measurement was taken in the VPP motor room, close to two motors that were running simultaneously. The microphone was located approximately 8 feet from the center axis of the first motor and 10.5 feet from the center axis of the second motor. At this location, the measured noise level () was 83.6 dba; this noise level included both direct noise from each motor and reverberant noise caused by sound reflected within the concrete- walled room. The second measurement was taken in the VPP pump room, close to two pumps that were running simultaneously. The microphone was located approximately 11 feet from the center axis of the first motor and 12 feet from the center axis of the second motor. At this location the measured noise level () was 83.8 dba; this noise level included both direct noise from each pump and reverberant noise caused by sound reflected within the concrete- walled room. Construction Potential noise and vibration impacts associated with project construction activities were evaluated based on the Proposed Project s construction equipment schedule and phasing information. Noise Construction- related traffic noise was analyzed using calculations based on the Federal Highway Administration (FHWA) Traffic Noise Model (TNM) Version 2.5 Look- Up Tables (FHWA 2004). The inputs used in the traffic noise modeling included the estimated maximum daily truck trips specified in the Truck Traffic Analysis Data memo prepared for the project (Arcadis 2016a) and an assumed speed of 25 miles per hour on the local streets closest to the Project Site. Construction- related noise was analyzed using data and modeling methodologies from FHWA s Roadway Construction Noise Model (RCNM) (FHWA 2006, 2008), which predicts average noise levels at nearby receptors by analyzing the type of equipment, the distance from source to receptor, usage factor, and the presence or absence of intervening shielding between source and receptor. This methodology calculates the composite average noise levels for multiple equipment items

16 scheduled during each construction phase. The source- to- receptor distances used in the analyses were the acoustical average distances between the relevant construction area and each receptor. The acoustical average distance is used to represent noise sources that are mobile or distributed over an area (such as the Project Site); it is calculated by multiplying the shortest distance between the receiver and the noise source area by the farthest distance and then taking the square root of the product. Noise levels for each phase of construction were analyzed at five receptors in the vicinity of the Project Site. These receptors are illustrated in Figure 3.9-2, and represent the closest noise- sensitive receptors (i.e., homes) in each direction from the Project Site. Table provides the noise levels of construction equipment expected to be used by the Proposed Project; the noise levels are provided for a reference distance of 50 feet. Consistent with the RCNM methodology, it was assumed that construction noise levels would be reduced at a rate of 6 db per doubling of distance from the source. Table Construction Equipment Noise Levels Equipment Item Maximum Noise Level (L max) at 50 feet, dba a Usage Factor a, b Excavator Backhoe Grader Jack Hammer Crane Compactor Pile Driver Air Compressor Concrete Trucks Notes: Average Noise Level () at 50 feet, dba a Obtained or estimated from FHWA 2006, 2008 (RCNM). b Usage Factor is the fraction of time the equipment is operating in its noisiest mode while in use. Leq is estimated from Lmax using the following equation: Leq = Lmax + 10 log10 (Usage Factor) Source: ICF, 2015 Vibration Construction- related vibration was analyzed using data and modeling methodologies provided by Caltrans Transportation and Construction Vibration Guidance Manual (California Department of Transportation 2013b). This guidance manual provides typical vibration source levels for various types of construction equipment, as well as methods for estimating the propagation of ground- borne vibration over distance. Because potential vibration impacts are assessed based on peak levels, rather than long- term average levels, the source- to- receptor distances used in the analyses were the estimated range of distances (closest to farthest) between the relevant construction activity and each receptor. Table provides the PPV levels of worst- case construction equipment expected to be used by the Proposed Project; the levels are provided for a reference distance of 25 feet

17 K:\Irvine\GIS\Projects\LABOE\00476_15\mapdoc\Noise\Fig_3_9_2_Nois_Analysis_Locations.mxd Date: 10/5/ Legend Noise Receptor Location Project Site Feet Imagery Source: Microsoft Bing Aerial (2016) ± Figure Noise Analysis Locations Project

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19 Table Construction Equipment Vibration Levels Equipment Item Pile driver 0.65 Large bulldozer b Notes: Reference PPV at 25 feet, in/s a a Obtained from California Department of Transportation 2013b. b Considered representative of other heavy earthmoving equipment such as excavators, graders, backhoes, etc. Source: ICF, 2015 The following equations from the guidance manual were used to estimate the change in PPV levels over distance. For pile driving, the equation is: PPV rec = PPV ref (25/D) n (E equip/e ref) 0.5 where PPV rec is the PPV at a receiver; PPV ref is the reference PPV at 25 feet from the pile driver (0.65 in/s); D is the distance from the pile driver to the receiver, in feet; n is a value related to the vibration attenuation rate through ground (the default recommended value for n is 1.1); E ref is 36,000 foot- pounds (rated energy of reference pile driver); and E equip is the rated energy of the actual impact pile driver in foot- pounds. (For the purposes of the analysis, it is assumed that the pile driver would be very similar to the reference pile driver and there would, therefore, be no adjustment for E equip.) For heavy earthmoving equipment such as excavators, graders, and backhoes, the equation is: PPV rec = PPV ref (25/D) n where PPV rec is the PPV at a receptor; PPV ref is the reference PPV at 25 feet from the equipment (0.089 in/s); D is the distance from the equipment to the receiver, in feet; and n is a value related to the vibration attenuation rate through ground (the default recommended value for n is 1.1). Operation Potential noise and vibration impacts associated with project operations were evaluated based primarily on information provided in the project s Preliminary Design Report (PDR) (Arcadis 2016b). This information included the general project description, preliminary plans, and preliminary specifications for equipment at VAPP that would generate noise. For some equipment, noise data were provided within the PDR; for other equipment representative or additional noise data were obtained from publicly available manufacturers specifications or predicted using published algorithms (Barron 2003). It was assumed that noise levels would be reduced at a rate of 6 db per doubling of distance from the source and the noise levels at sensitive receptors were estimated using standard decibel calculations, including the following. 1. To calculate the change in sound level due to a change in the number of identical equipment items operating: Δ= 10 log 10 (A/B) where Δ is the change in total noise level in db; A is the new number of equipment items; and B is the new number of equipment items

20 2. To calculate a sound pressure level from a stated sound power level: SPL = SWL + DI - 20 log 10 (D) 10.9 (Barron 2003) where SPL is the resulting sound pressure level in db; SWL is the stated sound power level in db; DI is the directivity index (with a value of 3 for hemispherical spreading across the ground); and D is the distance from the noise source in feet. 3. To calculate the change in sound pressure level with distance: Screening Analysis SPL rec = SPL ref + 20 log 10 (D ref/d rec) where SPL rec is the sound pressure level, in db, at a receiver; SPL ref is the sound pressure level, in db, at a reference distance; D ref is the reference distance, in feet, from the noise source; and D rec is the receiver distance, in feet, from the noise source. As noted in Chapter 1.0, Introduction, the analysis and conclusions contained in the Initial Study (see Appendix A [Notice of Preparation/Initial Study] of this EIR) prepared for the Proposed Project considered and then eliminated a number of impacts from further analysis, including those contained in Appendix G of the CEQA Guidelines and the L.A. CEQA Thresholds Guide (2006). Therefore, only those impacts and corresponding thresholds of significance noted below were determined to require further analysis and are addressed in this EIR Thresholds of Significance Appendix G of the State CEQA Guidelines provides six criteria, in the form of checklist questions a through e, that can be used to assess the significance of potential noise and vibration impacts. For some (but not all) of these criteria, the L.A. CEQA Thresholds Guide provides additional guidance on how potential impacts should be quantified or assessed. Where specific guidance is provided by the L.A. CEQA Thresholds Guide, those thresholds have been used as the basis for assessment of project impacts. For the any remaining criteria, the checklist questions provide the basis of the analysis, with specific thresholds developed, as necessary, from alternate sources as described below. State CEQA Guidelines, Appendix G The six checklist questions related to potential noise impacts are listed below, followed by a discussion of how each is addressed in this EIR. Would the project result in: NOI- 1. Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? NOI- 2. Exposure of persons to or generation of excessive ground- borne vibration or ground- borne noise levels? NOI- 3. A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project?

21 NOI- 4. A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? NOI- 5. For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? NOI- 6. For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? To address checklist questions NOI- 1, NOI- 3, and NOI- 4, the L.A. CEQA Thresholds Guide provides separate criteria for construction noise and operational noise; these criteria are described below and are used in place of checklist questions NOI- 1, NOI- 3, and NOI- 4 to address potential construction and operational noise impacts. Checklist question NOI- 2 does not quantify what would constitute excessive ground- borne vibration or ground- borne noise levels, and the L.A. CEQA Thresholds Guide does not provide any vibration criteria; therefore, thresholds for this potential impact have been developed based on guidance from Caltrans, as described below. As discussed above, Project implementation would result in no noise impacts related to airports or airstrips, so these issue areas are not included in this analysis and no further discussion of checklist questions NOI- 5 or NOI- 6 is provided. City of Los Angeles CEQA Thresholds Guide Construction Noise The following threshold of significance for construction noise is based on the L.A. CEQA Thresholds Guide (2006). The project would have a significant construction noise impact if: NOI- 7. Construction activities lasting more than 1 day would exceed existing ambient exterior noise levels by 10 dba or more at a noise- sensitive use; NOI- 8. Construction activities lasting more than 10 days in a 3- month period would exceed existing ambient exterior noise levels by 5 dba or more at a noise- sensitive use; or NOI- 9. Construction activities would exceed the ambient noise level by 5 dba at a noise- sensitive use between the hours of 9:00 p.m. and 7:00 a.m. Monday through Friday, before 8:00 a.m. or after 6:00 p.m. on Saturday, or at any time on Sunday. Proposed CEQA Threshold for Vibration The L.A. CEQA Thresholds Guide (2006) does not include thresholds for vibration impacts. Because project construction would generate ground- borne vibration, the City uses guidance from Caltrans Transportation and Construction Vibration Guidance Manual (California Department of Transportation 2013b) to determine the threshold of impact for vibration. Guidelines are provided for two types of potential impact: (1) damage to structures, and (2) annoyance of people. Guideline criteria for each are provided in Tables and

22 Table Caltrans Guideline Vibration Damage Criteria Structure and Condition Extremely fragile historic buildings, ruins, ancient monuments Transient Sources Maximum PPV (in/s) Continuous/Frequent Intermittent Sources Fragile buildings Historic and some old buildings Older residential structures New residential structures Modern industrial/commercial buildings Notes: Transient sources create a single isolated vibration event, such as blasting or drop balls. Continuous/frequent intermittent sources include impact pile drivers, pogo- stick compactors, crack- and- seat equipment, vibratory pile drivers, and vibratory compaction equipment. Source: California Department of Transportation, 2013b. Table Caltrans Guideline Vibration Annoyance Criteria Human Response Transient Sources Maximum PPV (in/s) Continuous/Frequent Intermittent Sources Barely perceptible Distinctly perceptible Strongly perceptible Severe Notes: Transient sources create a single isolated vibration event, such as blasting or drop balls. Continuous/frequent intermittent sources include impact pile drivers, pogo- stick compactors, crack- and- seat equipment, vibratory pile drivers, and vibratory compaction equipment. Source: California Department of Transportation, 2013b. The construction equipment used at the Project Site would fall into the continuous/frequent intermittent sources category. Based on these guidelines, the following thresholds will be used to assess potential vibration impacts: NOI- 11. The project would have a significant vibration impact, relative to potential building damage, if NOI- 13. PPV vibration levels from construction equipment are 0.3 in/s or greater at any existing residential structure, or 0.5 in/s at the adjacent VPP structure. NOI- 12. The project would have a significant vibration impact, relative to potential annoyance, if NOI- 15. PPV vibration levels from construction equipment are 0.04 in/s or greater (distinctly perceptible) at any existing residence

23 Operational Noise The following impact threshold for operational noise is based on the L.A. CEQA Thresholds Guide (2006). NOI- 13. The project would have a significant operational noise impact if it causes: l The ambient noise level measured at the property line of affected uses to increase by 3 dba in to or within the normally unacceptable or clearly unacceptable categories, or any 5 dba or greater noise increase (refer to Table 3.9-3, above). For residences this means a significant impact would occur if the project caused the ambient noise level to increase by 3 db or more to 70 db or greater, or to increase by 5 db or more to less than 70 db Construction Impacts The analysis below describes the temporary impacts related to noise and vibration as a result of the Proposed Project during construction. NOI- 1: Would project construction noise exceed any of the construction noise criteria provided by the L.A. CEQA Thresholds Guide (i.e., exceed existing ambient exterior noise levels by 10 dba or more at a noise- sensitive use for activities lasting more than 1 day; or exceed existing ambient exterior noise levels by 5 dba or more at a noise- sensitive use for construction activities lasting more than 10 days in a 3- month period, or activities occurring between the hours of 9 p.m. and 7 a.m. Monday through Friday, before 8 a.m. or after 6 p.m. on Saturday, or at any time on Sunday? Two types of short- term noise impacts could occur during construction of the Proposed Project. The first would be related to construction traffic construction workers who commute to the site and trucks that transport equipment and materials. The second would be on- site construction activities at the Project Site and loading/unloading activities at the three proposed construction laydown areas (see Figure 2-2 in Chapter 2, Project Description). Construction traffic would incrementally increase noise levels on access roads, including Pacific Avenue, Via Dolce, and Canal Court. Construction workers would be required to park off site and then travel to and from the site by shuttle, which would serve to minimize the number of vehicle trips on local streets to and from the Project Site. No construction worker parking would be allowed along Hurricane Street or on adjacent streets. Although there would be a relatively high single- event noise level, which could cause an intermittent noise nuisance (e.g., passing trucks at 50 feet would generate up to 76 dba), the contribution of construction traffic to ambient noise levels (such as the daily ) would be low due to the infrequent traffic volume. Based on data provided by the Project Engineer (Fehr & Peers 2016) 1, there could be up to 24 trucks per day to haul soil to or from the site. To provide a conservative analysis, it was assumed that each truck could travel on the same roadway twice during a round trip (for a total of 48 individual trips). The analysis indicates these truck trips would generate a noise level of up to 52 db at the homes adjacent to access roads (refer to Appendix I of this EIR for additional details). This is below the range of existing noise levels measured in the surrounding community (53 to 57 db ). Therefore, construction traffic would not increase ambient noise levels by 3 db or more. As a result, short- term impacts associated with construction- related traffic driving to and from the Project Site would be less than significant and no mitigation is required. 1 Fehr & Peers Trip Generation Analysis Project. LA Los Angeles, CA