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Home My WebLink AboutCT 15-11; YADA FAMILY FARM SUBDIVISION; NOISE ASSESSMENT; 2015-12-16I I I I I I I I I I I I I ~ I I l Jn ~nsull'ing, lne. 42428 ~hi~Dim Tr~iL Murrie/~, t:.A '/:l5f,:l phDne 1W-41J-I:l~ www.ltlnUJnlulling.nel 611' 1{,/}-{,g'f-4'/41 December 16, 2015 Yada Family Trust 31 Rolling Green Irvine, CA 92620 Subject: Buena Vista 14 (Yada) Single-family Residential Development Noise Assessment-carlsbad CA The firm of Ldn Consulting, Inc. is pleased to submit the following noise impact analysis for the proposed Buena Vista 11 (The Enclave) residential development in the City of Carlsbad. The purpose of the survey is to determine the estimated exterior noise levels at the proposed residential uses and recommend mitigation measures for compliance with the City of Carlsbad guidelines and requirements for noise. PROJECT LOCATION/DE$CRIPTION The proposed project is located within the City of Carlsbad, CA. More specifically, the project site is located on the northeast intersection of McCauley Lane and Valley Street. Buena Vista Avenue provides the northern property boundary. Access to the project site would be taken from both Buena Vista Avenue and via a new cul-de-sac. A general project vicinity map is shown in Figure 1. The proposed project would subdivide an existing 4.14-acre site into 14 separate lots. Currently there is an existing single family home on the site which will remain and 13 new homes would be constructed. The existing site conditions are characterized as disturbed land which is currently utilized for agricultural purposes. Both residential and agricultural uses surround the project site. The project site plan is shown in Figure 2. 12/16/2015 1 15145-03 Buena Vista 14 Noise Yada Family Trust 31 Rolling Green Irvine, CA 92620 12/16/2015 Figure 1: Project Vicinity Map @ : cr @ 1 w 2 IVfYRANi.:H /RANCHv DEL DRD MIRACDSTA MiraCosta College ~ I Lake Blvd McClellan-Palomar .. Airport ... Source: Google Maps, 2015 15145-03 Buena Vista 14 Noise ·-• ... - • • .... ... .... ... • .. .. • • Yada Family Trust 31 Rolling Green Irvine, CA 92620 ·~I L ~~-____! .J / 12/16/2015 Ldn &«.u~Nng, lne.. Figure 2: Project Site Plan 3 -,.._,.__,, 4Z4Z.S t;/Jif4/m Tr~i£ Murrie~, ~ '/25{,2 phone 7(,()-4n-125J F~" 1(,()-VBf-4141 I I I I '-----:__.-_L --~ --,_ -L ~- ~----------------{ c ~ : < . < :N; ---- / r '/ Source: BHA, Inc., 2015 15145-03 Buena Vista 14 Noise .. ... • .... • ... .. , • • • • .. .. ... Yada Family Trust 31 Rolling Green Irvine, CA 92620 ACOUSTICAL FUNDAMENTALS LJn~/ne,. 424211 c.hillllm Tr.til Murrief.t. C.A '12~2 phone 7/,o-4""-12~ F.tll 7/,o-{,Bf-414~ Noise is defined as unwanted or annoying sound which interferes with or disrupts normal activities. Exposure to high noise levels has been demonstrated to cause hearing loss. The individual human response to environmental noise is based on the sensitivity of that individual, the type of noise that occurs and when the noise occurs. Sound is measured on a logarithmic scale consisting of sound pressure levels known as a decibel (dB). The sounds heard by humans typically do not consist of a single frequency but of a broadband of frequencies having different sound pressure levels . The method for evaluating all the frequencies of the sound is to apply an A-weighting to reflect how the human ear responds to the different sound levels at different frequencies. The A-weighted sound level adequately describes the instantaneous noise whereas the equivalent sound level depicted as Leq represents a steady sound level containing the same total acoustical energy as the actual fluctuating sound level over a given time interval. The Community Noise Equivalent Level (CNEL) is the 24 hour A-weighted average for sound, with corrections for evening and nighttime hours. The corrections require an addition of 5 decibels to sound levels in the evening hours between 7 p.m. and 10 p.m. and an addition of 10 decibels to sound levels at nighttime hours between 10 p.m. and 7 a.m. These additions are made to account for the increased sensitivity during the evening and nighttime hours when sound appears louder. CNEL values do not represent the actual sound level heard at any particular time, but rather represents the total sound exposure. Additionally, Sound Transmission Class (or STC) is an integer rating of how well airborne sound is attenuated by a building partition. STC is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations (see ASTM International Classification E413 and E90). The STC number is derived from tested sound attenuation values found at the 1/3 octave band frequencies. These transmission-loss (TL) values are then plotted and compared to a standard reference contour. Acoustical engineers fit these values to the appropriate TL Curve to 12/16/2015 4 15145-03 Buena Vista 14 Noise ... ... • .. .• ... • .. • ... '"' • Yada Family Trust 31 Rolling Green Irvine, CA 92620 J.4n &«<MMIttng, lne. 42428 t:hiiDim Tr.li£ Murrilu, t:A 125/12 phone 7(,()-41'*-12~ F.1J 7(,()-(,Sf-414~ determine a single STC value found at 500 Hertz. STC is roughly the decibel reduction in noise a partition can provide, abbreviated 'dB' . If an 85 dB sound on one side of a wall is reduced to 50 dB on the other side, that partition is said to have an STC of 35. This number does not apply across the range of frequencies because the STC value is derived from a curve-fit from the tested 1/3 octave band frequencies. Any partition will have less TL at lower frequencies. For example, a wall with an STC of 35 may provide over 40 dB of attenuation at 3000Hz but only 15 dB of attenuation at 125 Hz . NOISE STANDARDS The City of Carlsbad's Noise Guidelines Manual (1995) requires that all exterior sensitive areas shall limit noise exposure. For noise sensitive residential land uses, the City has adopted a policy which has established a "normally acceptable" exterior noise level goal of 60 dBA CNEL for the outdoor areas and an interior noise level of less than 45 dBA CNEL. For residential properties identified as requiring a noise study, a study shall be prepared by an acoustical professional. This study shall document the projected maximum exterior noise level and mitigate the projected exterior noise level to a maximum allowable noise level as identified in Noise Guideline Manual. Interior noise levels should be mitigated to a maximum of 45 dBA CNEL in all habitual rooms when the exterior of the residence are exposed to levels of 60 dBA CNEL or more. If windows and doors are required to be closed to meet the interior noise standard, then mechanical ventilation shall be provided per City requirements. ANALYSIS PROCEDURES Existing Noise Levels Noise measurements were taken Friday December 11, 2015, using a Larson-Davis Model LxT Type 1 precision sound level meter, programmed, in "slow" mode, to record noise levels in "A" weighted form. The sound level meter and microphone were mounted on a tripod, five feet above the ground and equipped with a windscreen 12/16/2015 5 15145-03 Buena Vista 14 Noise ... ... , ''" ''" .. •• .. ... .. ... ... Yada Family Trust 31 Rolling Green Irvine, CA 92620 1-dn~/ne. 424%8 C.h~lm Tr~it Murr~f~. c.A f%~2 phDnl 7f,o-41J-12~ F~" 7t,o-(,8f-414~ during all measurements. The sound level meter was calibrated before and after the monitoring using a Larson-Davis calibrator, Model CAL 200. Monitoring location 1 (Mll) was located in the future location of Lot 1 along Buena Vista Way; monitoring location 2 (ML2) was located in the future location of Lot 11 along Valley Street. The results of the noise level measurements are presented in Table 4-1. The noise measurements were monitored for a time period of 20 minutes during normal traffic conditions. The existing noise levels in the Project area consisted primarily of residential activities, a half a dozen vehicles along the adjacent roadways and some background noise from traffic along Carlsbad Village Drive. The ambient Leq noise levels measured in the area of the Project were found to be 52-56 dBA. The statistical indicators Lmax, Lmin, L10, L50 and L90, are given for the monitoring location. As can be seen from the L90 data, 90% of the time the noise level was lower than 48 dBA. The lower noise levels are due to the limited vehicle traffic on the adjacent roadways and the horizontal off set between Carlsbad Village Drive and the Project site. The noise monitoring locations are provided graphically in Figure 3 on the following page . Table 4-1: Measured Ambient Noise Levels M1 Lot 1 1:05-1:25 p.m. 52.4 68.4 44.3 53.3 49.4 46.9 M2 Lot 11 1:30-1:50 p.m. 56.2 70.2 45.6 56.9 50.0 47.8 Source: Ldn Consulting 12/16/2015 6 15145-03 Buena Vista 14 Noise ... ... .. .,, ... Yada Family Trust 31 Rolling Green Irvine, CA 92620 xr L __ 12/16/2015 LJn &«<lluullng, /ne,. 42428 ChiiiJ/m Tr;,i£ MuiT"i#IJI. c.A 12~2 phone 7(,()-4""-12~ F111< 7{,()-{,S'f-4141 Figure 3: Ambient Noise Monitoring Locations ----10 I L_.-____ _L_.. -----~ BUENA VISTA AVE. _ ALi"!:lfit.TE! grJEEr iiiX.A.n (NO~ PF4QPOIJ3)) / --- 7 I ' I "------_. _ __]_ __ j ___ _ La--------·~---- f I 15145-03 Buena Vista 14 Noise •• ... .. "'' .. , .,, • .. .. ... ... .. ... .... - Yada Family Trust 31 Rolling Green Irvine, CA 92620 Future Noise Levels LJn ~ng, lne. 42428 t;hmolm Tr~i£ Murri#u, t:.A 12~2 phone 7W-4'"-12~ F~-,. 7t,o-t,8f-414"* The primary source of noise impacts to the project site will be vehicular noise from adjacent Buena Vista Way and Valley Street and back ground noise from Carlsbad Village Drive located approximately 500 feet south of the project site. The projected roadway noise levels from vehicular traffic were calculated using the methods in the Highway Noise Model published by the Federal Highway Administration (FHWA Highway Traffic Noise Prediction Model, FHWA-RD-77-108, December, 1978). The FHWA Model uses the traffic volume, vehicle mix, speed, and roadway geometry to compute the equivalent noise level. A spreadsheet calculation was used which computes equivalent noise levels for each of the time periods used in the calculation of CNEL. Weighting these equivalent noise levels and summing them gives the CNEL for the traffic projections . Mobile noise levels radiant in an almost oblique fashion from the source and drop off at a rate of 3 dBA for each doubling of distance under hard site conditions and at a rate of 4.5 dBA for soft site conditions. Hard site conditions consist of concrete, asphalt and hard pack dirt while soft site conditions exist in areas having slight grade changes, landscaped areas and vegetation. The future traffic noise model utilizes a typical vehicle mix of 97.9% Autos, 1.8% Medium Trucks and 0.3% Heavy Trucks for all roadways per the City guidelines. The vehicle mix provides the hourly distribution percentages of automobile, medium trucks and heavy trucks for input into the FHWA Model. Future year 2030 traffic along Buena Vista Way and Valley Street is predicted to be at most 900 average daily trips (ADT). Carlsbad Village Drive is expected to have 18,500 ADT according to the SANDAG Series 12 Traffic Prediction Model for the year 2035. The speed limit along Buena Vista Way and Valley Street is 25 MPH and 40 MPH on Carlsbad Village Drive. Based on the exterior noise model, the worst-case cumulative noise level from all the roadways was found to be 58.9 dBA CNEL at the site. The modeling results are provided in Figure 4 on the following page. No noise barriers, existing structures or topography that may affect noise levels were incorporated in the calculations . 12/16/2015 8 15145-03 Buena Vista 14 Noise .. ... • • .. Ill • ..,, • - .. .. .. .. .. Yada Family Trust 31 Rolling Green Irvine, CA 92620 LJn &8nllulllng, lne. 42428 C.hiNJ/m TrMl Murri#f~. CA f25f,2 p/IDM 7(,o-4""-12~ F~-,. 7t,o-(,1Jf-414~ Figure 4: Future Cumulative Noise Levels Project Name: Project Number: Mix Ratio by Percent Propagation Rule Roadway Buena Vista Way Valley Street carlsbad Village Drive Buena Vista Way Valley Street carlsbad Village Drive Cumulative Noise Level Combined Roadway Noise Levels Buena Vista 14 15-145 Date: Location: Tratfic Volumes, Mix an[Speeds Soft 15-Dec-15 Carlsbad ADT Speed MPH CNEL 0 SO Feet 60 CNEL (Fed) 900 900 18,500 25 51.5 13 25 51.5 13 40 69.5 215 Noise Reduction due to Distance Distance Reduction 40 1.45 40 1.45 390 -13.38 Resultant Level 52.9 52.9 56.1 59.0 dBACNEL Based upon these findings the future noise levels were found to be at or below 60 dBA CNEL and no noise mitigation is required to comply with the City of Carlsbad Noise standards. If you have any questions, please do not hesitate to contact me directly at (760) 473-1253 . Sincerely, Ldn Consulting, Inc • ~ Jeremy Louden, Principal 12/16/2015 9 15145-03 Buena Vista 14 Noise