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HomeMy WebLinkAboutCT 2018-0001; WALNUT BEACH HOMES; NOISE STUDY; 2017-12-01I. I I ' . 362 WALNUT A VENUE RESIDENTIAL PROJECT NOISE STUDY Prepared for: Rincon Real Estate Group Prepared by: 4])G)0 BIRDSEYE PLANNING GROUP December 2017 •• . ' - 362 Walnut Avenue Noise Study Table of Contents Page Project Description ..................................................................................................................................... 1 Setting .......................................................................................................................................................... 1 Overview of Sound Measurement ................................................................................................. 1 Sensitive Receptors .......................................................................................................................... 4 Project Site Setting ............................................................................................................................ 4 Regulatory Setting ............................................................................................................................ 7 Impact Analysis .......................................................................................................................................... 8 Methodology and Significance Thresholds .................................................................................. 8 Temporary Construction Noise ...................................................................................................... 9 Construction Noise Reduction Measures ................................................................................... 10 Residual Impacts ............................................................................................................................ 11 Temporary Construction-Related Vibration .............................................................................. 11 Long-Term Operational Noise Exposure .................................................................................... 12 References ................................................................................................................................................. 15 List of Figures Figure 1 -Project Location ........................................................................................................................ 2 Figure 2 -Proposed Site Plan ................................................................................................................... 3 Figure 3 -Noise Monitoring Locations ................................................................................................... 6 List of Tables Table 1 -Noise Monitoring Results ......................................................................................................... 7 Table 2 -Typical Construction Equipment Noise Levels .................................................................... 9 Table 3 -Typical Maximum Construction Noise Levels at Various Distances from Project Construction ................................................................................................................ 10 Table 4 -Vibration Source Levels for Construction Equipment.. ..................................................... 12 Appendices Appendix A Noise Monitoring Data 0Q© BIRDSEYE f'LANNING GROUP TOC 362 Walnut Avenue Noise Study ,... I ..... ,/ 362 WALNUT AVENUE CARLSBAD, CALIFORNIA NOISE STUDY This report is an analysis of the potential noise impacts associated with the 362 Walnut Avenue project, an 11-unit condominium development proposed for construction in the City of Carlsbad. The report has been prepared by Birdseye Planning Group, LLC, under contract to the applicant to support the environmental review process and address comments provided by the City of Carlsbad after review of the project entitlement submittal. This study analyzes the potential for temporary impacts associated with construction activity and long-term impacts associated with operation of the proposed project. PROJECT DESCRIPTION The project is located on the north side of Walnut Avenue between Lincoln Street to the west and the railroad right-of-way to the east and would replace an existing single-family residence, guest house and detached garage with a new a new 11-unit multifamily residential building. Construction would require the demolition and removal of the existing residence, over-excavation of the top three feet of soil, installation of infrastructure improvements and construction of the new buildings. Construction is anticipated to begin in early 2018 and be completed by late 2018. Figure 1 provides a vicinity map; Figure 2 shows a project site plan. SETTING Overview of Sound Measurement Noise level (or volume) is generally measured in decibels (dB) using the A-weighted sound pressure level (dBA). The A-weighting scale is an adjustment to the actual sound pressure levels to be consistent with that of human hearing response, which is most sensitive to frequencies around 4,000 Hertz (about the highest note on a piano) and less sensitive to low frequencies (below 100 Hertz). Sound pressure level is measured on a logarithmic scale with the 0 dB level based on the lowest detectable sound pressure level that people can perceive (an audible sound that is not zero sound pressure level). Based on the logarithmic scale, a doubling of sound energy is equivalent to an increase of 3 dBA, and a sound that is 10 dBA less than the ambient sound level has no effect on ambient noise. Because of the nature of the human ear, a sound must be about 10 dBA greater than the reference sound to be judged as twice as loud. In general, a 3 dBA change in community noise levels is noticeable, while 1-2 dB changes generally are not perceived. Quiet suburban areas typically have noise levels in the range of 40-50 dBA, while arterial streets are in the 50-60+ dBA range. Normal conversational levels are in the 60-65 dBA range, and ambient noise levels greater than 65 dBA can interrupt conversations. Noise levels typically attenuate (or drop off) at a rate of 6 dBA per doubling of distance from point sources (i.e., industrial machinery). Noise from lightly traveled roads typically attenuates at a rate of about 4.5 dBA per (])~@ BIRDSEYE PLANNING GROUP 1 c.. ro ~ > +-' C ·u > I 'l'""i Q) lo.. ::::, b.O u.. Figure 2 -Site Plan ._ .. ... " ":-\ ''N ss•sww E 220.06' l 2 --------..... _.;......,-·------... ------~------~~-----~ ------~ --... ... ~, . '"" i, t .... ~ ~ ----~ .... -· s~I __,_ 1.,,.,., 'n .s.a '"''-'Nl'r 11,-=.. t.WIU~ -............ -,,,_ -·~ L.. ll ,. -·T t,IO'tl.1 • '"""''""' , ..... ' ~ r ....-,,m -::.•I,=-...... =1 .!, ... - II-= l,~L -='·, ..... tMIU . '"'""""" , ..... -.. t~ -··•--..... .. . --- .., ' ·, .__ ---.,(-~ I 8ai, .... !.. =s ." • ., F-----.-----~-~ss-:se-56•£100~ -----... -~-~ r. -· HtUF ·-'"""" <M• I~-,.,_ -.. .... .... nu ll, . -- -:=" -· · -~ , )SfQRY ~ 1 ,_k, r-It, ... zutan' ~ 1-~ -· ur211 '""""""' ...... --.... .... 1 ·, ·~ ~ 1 i f .::.. .. PARCEL MAP425 ... ,- = CONCEPTUAL SITE PLAN .,. r~• i--• , w ..... ~4i~ I I l r I I I -JJJtS7-..a•_J _nt.;. __ '----... --------------~------__J APPROVED ....... ~""""ffl/11.,.,.,,..,. ""'-~--l'll!Ola.'f-----___ .,,. .... __ --.J..'1'.PIIHG.- a •1u• mJ MU Atc.iltcll ..................... ........ (, .. , .•• ,,,t• I! a ~ ~ !! •• -•• -w.i ':'.: .... ~I ~ < i5 i 1~- !:': ~ ~ --... _ __... ___ = SITT PV,N A1.1 362 Walnut Avenue Noise Study doubling of distance. Noise from heavily traveled roads typically attenuates at about 3 dBA per doubling of distance. Noise levels may also be reduced by intervening structures; generally, a single row of buildings between the receptor and the noise source reduces the noise level by about 5 dBA, while a solid wall or berm reduces noise levels by 5 to 10 dBA. The manner in which older homes in California were constructed (approximately 30 years old or older) generally provides a reduction of exterior-to-interior noise levels of about 20 to 25 dBA with closed windows. The exterior-to-interior reduction of newer residential units and office buildings is generally 30 dBA or more (HMMH, 2006). In addition to the actual instantaneous measurement of sound levels, the duration of sound is important since sounds that occur over a long period of time are more likely to be an annoyance or cause direct physical damage or environmental stress. One of the most frequently used noise metrics that considers both duration and sound power level is the equivalent noise level (Leq). The Leq is defined as the single steady A-weighted level that is equivalent to the same amount of energy as that contained in the actual fluctuating levels over a period of time (essentially, the average noise level). Typically, Leq is summed over a one-hour period. Lmax is the highest RMS (root mean squared) sound pressure level within the measuring period, and Lmin is the lowest RMS sound pressure level within the measuring period. The time period in which noise occurs is also important since noise that occurs at night tends to be more disturbing than that which occurs during the day. Community noise is usually measured using Day-Night Average Level (Ldn), which is the 24-hour average noise level with a 10-dBA penalty for noise occurring during nighttime (10 p.m. to 7 a.m.) hours, or Community Noise Equivalent Level (CNEL), which is the 24-hour average noise level with a 5 dBA penalty for noise occurring from 7 p.m. to 10 p.m. and a 10 dBA penalty for noise occurring from 10 p.m. to 7 a.m. Noise levels described by Ldn and CNEL usually do not differ by more than 1 dB. Sensitive Receptors Noise exposure goals for various types of land uses reflect the varying noise sensitivities associated with each of these uses. The City of Carlsbad General Plan Noise Element Update (approved September, 2015) includes a variety of land use and development types that are noise sensitive including residences, schools, churches, hospitals and convalescent care facilities. Sensitive receptors are located adjacent to the project site. Once constructed, the project will be a sensitive receptor. Single-and multifamily residences are the dominant land use in the area. Project Site Setting The most common and primary sources of noise in the project site vicinity are motor vehicles (e.g., automobiles, buses, trucks, and motorcycles) along Walnut Avenue. Motor vehicle can be a concern when it is characterized by a high number of individual events that can create a sustained noise level in proximity to noise sensitive uses. Interstate 5 is located approximately 2,600 feet to the east. It is audible as background noise and contributes to overall noise levels at the project site. QQ© BIRDSEYE PLANNING GROUP 4 362 Walnut Avenue Noise Study -~ .. The Atichson, Topeka and Santa Fe Railroad (AT&SF) rail corridor is located approximately 250 feet east of the site. This segment of the Los Angeles -San Diego -San Luis Obispo (LOSSAN) corridor is the second busiest passenger and freight rail corridor in the United States. According to the rail timetables, up to 50 trains (40 passenger and 10 freight trains) use the corridor segment daily between Oceanside and the Santa Fe Depot in downtown San Diego. Existing rail operations are audible at the project site, particularly the warning horns/bells that are used when trains are approaching or departing the Carlsbad Village Drive station located approximately 2,600 feet north of the site. Train noise contributes to the ambient noise environment in the study area. McClellan-Palomar Airport is located approximately 4.0 miles southeast of the site. The site is outside the airport influence area; however, aircraft operations (airplanes and helicopters) are audible and contribute to existing noise levels in the project area. No other noise sources are near the project site. The City of Carlsbad General Plan Update Noise Element (2015) provides noise contours associated with transportation corridors (i.e., roadways, railroad and airport). This provides a graphic illustration of sound levels near road corridors, but typically does not include effects of landforms and adjacent structures. Generally, barriers between a source and receiver absorb or reflect noise resulting in a quieter environment. Where barriers or landforms do not interrupt the noise transmission path from source to receiver, the contours prove to be reasonable estimates of typical noise levels from roadway traffic. In areas where barriers or landforms interrupt the sound transmission, the noise contours overestimate the extent to which a source intrudes into neighboring areas. The noise contour distances describe worst-case conditions because they do not account for any obstructions to the noise path, such as walls, berms, or buildings. As noted, railroad noise is audible when train pass-by events occur. The contours provided in the General Plan Update Noise Element provide a reasonable prediction of rail noise levels at the site. Noise contours show the project site is outside the 60-65 dBA CNEL contour interval defined for the railroad track and outside the 60-65 dBA CNEL contour line for 1-5. To gather data on the general noise environment at the project site, two weekday 15-minute noise measurement was acquired in proximity to the project site on December 20 and 21, 2017, using an ANSI Type II integrating sound level meter. Because traffic was light on Walnut Avenue during the December 20, 2017 monitoring episode, a second measurement was taken during the morning commute period on December 21, 2017 to confirm the monitoring results. The predominant noise source in the area during monitoring was traffic on Walnut Avenue. Aircraft overflights and a train pass by event contributed to ambient conditions during the December 20 monitoring period. During monitoring on December 20, 2017, a total of 7 cars/light trucks passed the monitoring site. A total of 3 cars/light trucks passed the monitoring site during the December 21, 2017 monitoring episode. One Am-Track pass and multiple helicopter overflights occurred during monitoring on December 20 which accounts for the higher levels. Table 1 identifies the noise measurement location and measured noise levels. The monitoring location is shown in Figure 3. As shown, the measured Leq' s were within 2 dBA. Monitoring data is provided as Appendix A. 0Q© BIRDSEYE PLANNING GROLJP 5 C 0 ·.p ro u 0 ,_J b.O C I.. 0 +-' C 0 ~ I ("f') Q) I.. :::::, b.O u.. 362 Walnut Avenue Noise Study -· Table 1 Noise Monitoring Results Measurement Location Primary Noise Source Project site located at 362 Walnut Avenue (12/20/17) Traffic/Rail/Aircraft Project site located at 362 Walnut Avenue (12/21/17) Traffic Source: Field visit using ANSI Type If Integrating sound level meter. Regulatory Setting Sample Time Leq (dBA) Weekday afternoon 58.4 Weekday morning 56.4 In 1976, the California Department of Health, State Office of Noise Control published a recommended noise/land use compatibility matrix which many jurisdictions have adopted as a standard in their general plan noise elements. This matrix indicates that residential land uses and other noise sensitive receptors preferentially should be located in areas where outdoor ambient noise levels do not exceed 65 to 70 dBA (CNEL or Ldn). Municipal Code and Noise Guideline Manual The City of Carlsbad has established noise guidelines in the Noise Element of the City's General Plan (City of Carlsbad, 2015) that are applicable for transportation noise sources. The noise guidelines identify compatible exterior noise levels for various land use types. Residential land uses are considered normally acceptable up to 60 dB CNEL. Commercial land uses are considered normally acceptable up to 65 dB CNEL and conditionally acceptable up to 75 dB. The City of Carlsbad Municipal Code regulates construction noise by limiting the hours of operation (City of Carlsbad 2003). Construction activities are allowed to occur Monday through Friday between the hours of 7 a.m. to sunset; and on Saturdays from 8 a.m. to sunset, excluding legal holidays. The City does not have quantitative noise level limits (i.e., based on sound levels) for general nuisance noise such as that associated with stationary equipment located on private property. For the purpose of this study, the residential standard of 60 dB CNEL is used to evaluate potential exterior noise impacts associated with the proposed project. An interior noise standard of 45 dBA CNEL is used herein as referenced in the City of Carlsbad Noise Guidelines Manual (1995). Vibration Standards Vibration is a unique form of noise as the energy is transmitted through buildings, structures and the ground whereas audible noise energy is transmitted through the air. Thus, vibration is generally felt rather than heard. The ground motion caused by vibration is measured as particle velocity in inches per second and is referenced as vibration decibels (VdB). The vibration velocity level threshold of perception for humans is approximately 65 VdB. A vibration velocity €)~© BIRDSEYE PLANNING GROUP 7 362 Walnut Avenue Noise Study -\. of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels. City policies do not address construction-related vibration; thus, for the purpose of evaluating project-related vibration impacts, thresholds established in the Federal Transit Administration's (FTA) Transit Noise and Vibration Impact Assessment (May 2006) are used. A threshold of 65 VdB is used for buildings where low ambient vibration is essential for interior operations. These buildings include hospitals and recording studios. A threshold of 72 VdB is used for residences and buildings where people normally sleep (i.e., hotels and rest homes). A threshold of 75 VdB is used for institutional land uses where activities occur primarily during the daytime (i.e., churches and schools). The threshold used for the proposed project is 72 VdB as multifamily residences are the only sensitive receptors in proximity to the site. Construction activities such as blasting, pile driving, demolition, excavation or drilling have the potential to generate ground vibrations near structures. With respect to ground-borne vibration impacts on structures, the FTA states that ground-borne vibration levels in excess of 100 VdB would damage fragile buildings and levels in excess of 95 V dB would damage extremely fragile historic buildings. No historic buildings are known to occur near the site; thus, 100 VdB is used to quantify potential vibration impacts to neighboring structures. Construction activities referenced above that would generate significant vibration levels are not proposed. However, to provide information for use in completing the CEQA evaluation, construction-related vibration impacts are evaluated using the above referenced criteria. IMPACT ANALYSIS Methodology and Significance Thresholds Construction noise estimates are based upon noise levels reported by the Federal Transit Administration, Office of Planning and Environment, and the distance to nearby sensitive receptors. Reference noise levels from that document were used to estimate noise levels at nearby sensitive receptors based on a standard noise attenuation rate of 6 dB per doubling of distance (line-of-sight method of sound attenuation). The site is currently a single-family residence; thus, noise levels associated with existing and future traffic were based on the difference in trip volumes between the existing volumes counted during monitoring and the proposed use. A doubling of traffic volumes would be required to cause a noticeable increase (3 dBA) in traffic noise. Thus, the two numbers were calculated to determine whether the project would generate enough traffic to increase noise levels by 3 dBA or more. This study also estimates potential noise levels at the project site related to operation of the AT&SF rail line which is located approximately 250 feet east of the site. A software program based on methodologies approved by the Federal Rail Administration was used to perform noise calculation associated with rail operations. Specific assumptions used in the analysis are described below. As noted, a noise increase greater than 3 dBA is readily perceptible to the average human ear; and thus, is the level considered a substantial noise increase related to traffic operations. However, within the City of Carlsbad, noise impacts are also considered significant if noise ©~© BIRDSEYE PLI\NN!NC GROUP 8 362 Walnut Avenue Noise Study levels would exceed 60 dBA CNEL. For the purpose of this evaluation, the peak hour Leq is used for traffic noise as it provides a more conservative estimate of potential noise levels. The CNEL is used within the rail noise discussion. Existing noise levels at the monitoring site do not exceed 60 dBA as referenced above; thus, the determination of impact is based on whether existing noise levels would increase and/ or cause noise levels to exceed 60 dBA with project implementation. All mechanical equipment associated with the project would be located within roof top enclosures or in the building mechanical area. Mechanical noise is not expected to be audible off-site. Temporary Construction Noise The main sources of noise during construction activities would include heavy machinery used during demolition, grading, and clearing the site, as well as equipment used during building construction and paving. Table 2 demonstrates the typical noise levels associated with heavy construction equipment. As shown, average noise levels associated with the use of heavy equipment at construction sites can range from 81 to 95 dBA at 25 feet from the source, depending upon the types of equipment in operation at any given time and phase of construction (Hanson, Towers, and Meister, May 2006). Table 2 Typical Construction Equioment Noise Levels Typical Level Typical Level (dBA) Typical Level (dBA) Equipment Onsite (dBA) 25 Feet 50 Feet from the 100 Feet from the from the Source Source Source Air Compressor 84 78 64 Backhoe 84 78 64 Bobcat Tractor 84 78 64 Concrete Mixer 85 79 73 Bulldozer 88 82 76 Jack Hammer 95 89 83 Pavement Roller 86 80 74 Street Sweeper 88 82 76 Man Lift 81 75 69 Dump Truck 82 76 70 Source: Noise levels based on FHWA Roadway Construction Noise Modef (2006) Users Guide Table 1. Noise levels based on actual maximum measured noise levels at 50 feet (Lmax). Noise levels assume a noise attenuation rate of 6 dBA per doubling of distance. As noted, adjacent properties are residential and construction noise will be audible at properties in proximity to the site. Table 3 shows typical maximum construction noise levels at various distances from construction activity, based on a standard noise attenuation rate of 6 dBA per doubling of distance. The noise level used to estimate the maximum noise level that could occur is based on use of a bobcat tractor as it is likely to be the noisiest type of equipment used over a 0Q© BIRDSEYE PLANNING GROUP 9 362 Walnut Avenue Noise Study /" ...... sustained period of time during demolition and site preparation activities. Actual noise levels will fluctuate throughout the day and may periodically exceed 84 dBA at the property line depending on the type and location of equipment used and whether multiple pieces of equipment are operating simultaneously in the same area. Table 3 Typical Maximum Construction Noise Levels at Various Distances from Project Construction Distance from Maximum Noise Level at Construction Receptor (dBA) 25 feet 84 50 feet 78 100 feet 72 250 feet 66 500 feet 60 1,000 feet 54 Construction noise levels at neighboring residences could be as high as 84 dBA. However, temporary construction noise is not restricted if it occurs between the hours specified in the noise ordinance referenced herein. While not required, temporary construction noise can be reduced by implementing one or more of the following measures. Construction Noise Reduction Measures Temporary construction noise impacts could be reduced through implementation of the following measures: N-1 @Q© BIRDSEYE PLANNING GROUP Construction Equipment. Electrical power shall be used to run air compressors and similar power tools. Internal combustion engines should be equipped with a muffler of a type recommended by the manufacturer and in good repair. All diesel equipment should be operated with closed engine doors and should be equipped with factory-recommended mufflers. Construction equipment that continues to generate substantial noise at the project boundaries should be shielded with temporary noise barriers, such as barriers that meet a sound transmission class (STC) rating of 25, sound absorptive panels, or sound blankets on individual pieces of construction equipment. Stationary noise-generating equipment, such as generators and compressors, should be located as far as practically possible from the nearest residential property lines. 10 362 Walnut Avenue Noise Study N-2 N-3 Residual Impacts Limit Operations Adjacent to Receivers. Limit the number of large pieces of equipment (i.e., backhoes or concrete mixers) operating adjacent to receivers to one at any given time. Neighbor Notification. Provide notification to residential occupants nearest to the project site at least 24 hours prior to initiation of construction activities that could result in substantial noise levels at outdoor or indoor living areas. This notification should include the anticipated hours and duration of construction and a description of noise reduction measures being implemented at the project site. The notification should include a telephone number for local residents to call to submit complaints associated with construction noise and be easily viewed from adjacent public areas. Project construction would represent a temporary source of noise at the project site. Measures N-1 through N-3 could reduce construction noise impacts. No residual impacts associated with construction noise are anticipated. Temporary Construction-Related Vibration Activities associated with residential projects do not generate vibration. Thus, this discussion will focus on temporary vibration caused by construction. Based on the information presented in Table 4, vibration levels could reach 87 VdB at the buildings nearest the site during construction assuming a bulldozer is the heaviest piece of equipment used during demolition. As discussed below, 100 VdB is the threshold where minor damage can occur in fragile buildings. Vibration levels are projected to be under this threshold; thus, structural damage is not expected to occur as a result of construction activities associated with the proposed project. Vibration levels at residential buildings adjacent to the project site may exceed the groundbome velocity threshold level of 72 V dB for residences and/ or buildings where people sleep as discussed above. Maximum vibration levels would range from 58 to 87 VdB depending on the type of equipment used. However, as long as construction occurs within the prescribed hours, any temporary impact would be considered adverse, but less than significant. OQ© BIRDSEYE PLANNING GROUP 11 362 Walnut Avenue Noise Study ~ .... Table 4 Vibration Source Levels for Construction Equipment Equipment Approximate VdB 25 Feet 50 Feet 60 Feet 75 Feet Large Bulldozer 87 81 79 77 Loaded Trucks 86 80 78 76 Jackhammer 79 73 71 69 Small Bulldozer 58 52 50 48 Sourc:e: Federal Railroad Administration, 1998 Long-Term Operational Noise Exposure 100 Feet 75 74 67 46 Exterior Traffic Noise. Traffic is the primary noise source that would be generated by the proposed project. Thus, whether a traffic-related noise impact would occur is based on whether the project would double peak hour traffic volumes relative to existing conditions or cause noise levels to exceed 60 dBA. The peak hour is defined as the one-hour period between 7:00 am and 9:00 am and 4:00 pm and 6:00 pm when the highest volumes occur. Traffic volumes for the project were based on evening peak hour trip generation rates published by the Institute of Transportation Engineers (!TE) publication Trip Generation, 8th Edition for condominiums/ apartments. Peak hour trips are assumed to be 10% of the ADT. For the purpose of this analysis, the residential uses would generate 0.62 peak hour trips per unit or 7 hourly trips. Existing peak hour volumes based on December 21, 2017 counts performed during noise monitoring, are 12 vehicles on Walnut Avenue. Thus, peak hour project trips (7) would not double existing volumes nor, based on existing noise levels, would the additional of project traffic have an adverse effect on noise levels at sensitive properties within proximity to the site. Project impacts with respect to exterior traffic noise would be less than significant. Interior Traffic Noise. The proposed project would be designed to meet or exceed California Energy Code Title 24 standards which specify construction methods and materials that result in energy efficient structures and up to a 30 dBA reduction in exterior noise levels (assuming windows are closed). When windows are open the insertion loss drops to about 10 dBA. Assuming windows are closed, interior noise levels associated with traffic operations would be reduced from 58.4 (baseline) to 28.4 dBA which would be below the 45 dBA standard. Exterior Railroad Noise. The AT&SF corridor is located approximately 250 feet to the east of the site and is used by Amtrak and the North County Transit District Coaster to provide passenger rail service. It is also used by freight trains during the late evening and nighttime hours. Based on the time tables, approximately 50 trains operate daily within this segment. Train volumes vary throughout the day but are generally higher during the morning and evening commute hours and reflect the dominant use of this corridor by commuter rail and passenger trains. (i)Q@ BIRDSEYE PLANNING GROUP 12 362 Walnut Avenue Noise Study Train noise is generated by a combination of factors including the number of locomotives, rail cars, speed, volume distribution over the day and nighttime hours and whether train horns are used. The existing rail noise levels at the project site were calculated using a proprietary software program based on Federal Rail Administration methodology. Because Coaster trains stop at the Carlsbad station (Amtrak and freight trains do not), which is located approximately 2,600 feet north of Walnut Avenue, it was assumed the average speed through the area is 35 miles per hour. It was assumed that each passenger train has one locomotive and 10 rail cars. For freight trains it was assumed they have two locomotives and 50 cars. Train warning horns were audible during monitoring; thus, it was assumed that train operators do use the warning horn when in proximity to the site. Of the 50 train pass by events each day, five freight operations were assumed to occur during the nighttime (10:00 p.m. to 7:00 a.m.) hours. Based on these assumptions, the exterior CNEL at the project site (located 250 feet west of the rail corridor) is approximately 69 dBA when both passenger and freight rail operations are combined. This does not consider the intervening topography that may reduce noise levels. The estimated CNEL is higher than the CNEL contours provided in the 2015 General Plan Update Noise Element for residential areas within the City of Carlsbad and would exceed the recommended CNEL for residential uses. Interior Railroad Noise. While the existing exterior CNEL at the site exceeds the standard recommended by the City of Carlsbad for residential uses, design features can be implemented to reduce interior noise levels to at least 45 dBA CNEL as specified in the City of Carlsbad Noise Guidelines Manual. As noted above, the proposed project would be designed to meet or exceed California Energy Code Title 24 standards which specify construction methods and materials that result in energy efficient structures and up to a 30 dBA reduction in exterior noise levels (assuming windows are closed). Assuming windows are closed, the CNEL associated with rail noise would be reduced from 69 dBA CNEL to 39 dBA CNEL which would be consistent with the local standards. No measures in addition to compliance with Title 24 design requirements would be necessary to reduce rail noise. Rail Vibration. As noted, the proposed project would be constructed approximately 250 feet west of the rail corridor. Thus, a screening evaluation of potential vibration impacts was performed to determine whether the project would be exposed to vibration levels that could be perceived by building residents. Because the project is a residential development, it would be considered a Category 2 land use for the purposes of vibration assessment as defined in the Federal Transit Administration, Transit Noise and Vibration Impact Assessment (2006). This category covers all residential land uses and any buildings where people sleep, such as hotels and hospitals. The impact criteria for a Category 2 land use is 75 VdB along corridors where train vibration events occur occasionally (i.e., 30 to 70 events daily). As noted, a vibration velocity of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels. A screening level evaluation was performed to determine the likelihood of vibrations from the LOSSAN corridor affecting the proposed project. The screening distance for conventional commuter railroads was used to account for both passenger and freight trains. The distance between a conventional commuter railroad and Category 2 land use where the potential for a vibration impact to occur is 200 feet as defined in Table 9.2 within the FTA noise and vibration @Q© BIRDSEYE PLANNING GROUP 13 362 Walnut Avenue Noise Study ( ' impact assessment methodology. The screening distances include a 5-decibel safety factor. The proposed project site is located outside the 200-foot screening distance; however, a general vibration assessment was performed to provide a more detailed evaluation of potential vibration impacts. The general vibration assessment methodology is provided in Chapter 10 of the assessment manual identified above. It is based on the use of a base curve to determine vibration as a function of distance from the track assuming a standard rail and ballast configuration. Using the diesel powered locomotive powered passenger or freight base curve (see Figure 10-1 in the Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual), the vibration level is 69.0 VdB at approximately 250 feet from the track at a reference speed of 50 miles per hour. Using a correction factor of 3 VdB for speed (35 in the study area vs. a 50 VdB reference level), the vibration level at the site is estimated at 66 VdB. This is likely conservative given the amount of ballast rock in the track bed and soil propagation; however, for the purpose of assessing potential vibration levels, projected vibration levels would not exceed the 72 VdB threshold. €,Q© BIRDSEYE PtANNlNG GROUP 14 362 Walnut Avenue Noise Study References ' City of Carlsbad. General Plan Update Noise Element. 2015. City of Carlsbad. Noise Guidelines Manual. September, 1995. ,,,. ...... Federal Highway Administration. Roadway Construction Noise Model. 2006. Users Guide Table 1. Federal Highway Administration, Transportation Noise Model Version 2.5, 2004. Federal Transit Administration. Transit Noise and Vibration Impact Assessment. May 2006. Federal Rail Administration (FRA) Guidelines (Report Number 293630-1), December 1998. Hanson, Carl E., Towers, David A., and Meister, Lance D. (2006, May). Transit Noise and Vibration Impact Assessment. Federal Transit Administration, Office of Planning and Environment. http://www.fta.dot.gov/ documents/FT A Noise and Vibration Manual.pd£ Harris Miller Miller & Hanson Inc. Transit Noise and Vibration Impact Assessment, Final Report. May 2006. Institute of Transportation Engineers (ITE) publication Trip Generation, 8th Edition 0Q© BIRDSEYE PLANNING GROUP 15 Appendix A Monitoring Data Sheet 0Q© Appendix A BIRDSEYE PLANNING GROUP • FkD NOISE MEASUREMENT DAl~ .. ??. /r-J 0,...,/ /! L/ -j-_ /-1 VC.?-: t/ ~ Page l of . Project Name: ·34:,_ '-- Project#: . Dav/ Date·/ ~i Zo/.Z,,1:-'ZQ() My Name. Sound Level Meter C2 librator r ·· Weathef Meter Modelt. ,'E_' 7 0,,,-..J Model# -Model# Serial# serial t. Serial# Weighting: ;@/ C / Flat Pre-Test: dBASPL Terrain: Hard/ Soft/~1x€0 .. I Response: · w /Fast/Imp! ~= Post-Test: dBA SP!.: Topo: _ ·· El.aLJ Hilly (describe) Windscreen: tie_it No ---, · Steady / Gusty Wind: ID Time Time Leq Lmin Lmax L10 LSO L90 Wind Spd/ Temp RH Bar Psr Cloud Start Stop Dir (mph) (OF) (%) (in Hg) Cover(%) ,, . I -i----~-ri T .1·0•, ,1tiP. !:-5.tVt 2Pt.1 '@lt.r7.~,r,:i ff!.7 .,,,._IQ.' /~2. -. ' i 'Ao', Q ?{) .-<;(..~•ZfJ.7.7L":~ •~-z.. ;;1:~ '7 -5::--1/J ~..,~ C?/-.-. ,. ' C !. ' . I • ·.;,i:::, '+"' • . I Roadway Na"le t,-.)tJ.....-f /J v 7'" A v6;•v UC Location(s) / GPS Readinp(s): I Speed (post/obs) 2. "7 .. i Number of Lanes '7 '-·· Width (pave/row) --z__q'I 1-or 2-way -z__ .. I Grade 1-z/ . i ' Bus Stops r./0 ·• .. .. Stoplights µO .. ' Street Parking 'f 6 ,; • Automobiles. ? -. . . --· ! Medium Trucks t) .• l Heavy Trucks 0 .. ~ l /Y' o-rt:-_. 7e.Ai/W ?e.ss_!!;'()r All'Z."--eA.<rJ o-~~~r,::r_,c::~-17s C 0'-'/12...11;,,% ~ ' 10 A ,,.,---r8/6,;,...;; c::_a,.-.,T),::;71 ~, ;:::. .. ? ~ d, /O(c .. d ,.,,,--,r-y ·D,, .. c_ -Zt j"'-01'-' ,"?"=>(--,,,<..,I (J---{5;V1 $' .. !)'Dk. ' I " Oth8r Noise Sources: cristan~~ ~ andscapi~ children playing/ dogs barking/ birds VOcalizing Notes and ~-ketches on Reverse -·:· ··-·•· ~----· ---. . .. . . -.. -;. ....