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HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Carlsbad Blvd Phase II Bridge & Basin; 2000-05-12NOISE TECHNICAL REPORT FOR CALAVERA HILLS MASTER PLAN PHASE II AND BRIDGE AND THOROUGHFARE DISTRICT NUMBER 4 CITY OF CARLSBAD, CALIFORNIA Prepared for PLANNING SYSTEMS 1530 FARADAY AVENUE, SUITE 100 CARLSBAD, CA 92008 Prepared by DAVDD M. GOTTFREDSON ACOUSTICIAN RECON NUMBERS 3225N/3226N MAY 12, 2000 1927 Fifth Avenue, Suite 200 San Diego, CA 92101-2358 619/ 308-9333 fax 308-9334 \ft Ttiis document printed on recycled paper TABLE OF CONTENTS Summary 1 A. Blasting 1 B. Grading 1 C. Materials Processing Centers 2 D. Future Traffic Generated Noise 2 Introduction 5 Analysis Methodology 10 A. AppUcable Standards and Definitions of Terms 10 B. Traffic Noise Analysis 12 Existing Conditions 14 Future Acoustical Environment and Impacts 15 A. Blasting 15 B. Grading 18 C. Materials Processing Centers 18 D. Future Traffic Generated Noise 23 Mitigation 48 A. Blasting 48 B. Grading 48 C. Materials Processing Centers 50 D. Future Traffic Generated Noise 50 References Cited 57 TABLE OF CONTENTS (cont.) FIGURES 1: Regional location of the project 6 2: Project vicinity map 7 3: Calavera Hills Master Plan villages 8 4: Aerial photograph of the project area 9 5: Potential blasting areas and potential blast noise impact areas 16 6: Limits of grading and potential construction noise impact area 19 7: Materials processing areas and potential noise impact areas 20 8: Projected future noise contours - Village H 25 9: Modeled receivers and proposed barrier locations - Village H 26 10: Projected future noise contours - Village K 28 11: Modeled receiver locations and proposed noise barriers - Village K 29 12: Projected future noise contours - Village U 32 13: Modeled receiver locations and proposed noise barriers - Village U 33 14: Projected future noise contours - Villages W, X, and Y 35 15: Modeled receiver locations and proposed noise barriers - Villages W, X, and Y 36 16: Modeled receiver locations and proposed noise barriers, Rancho Carlsbad Mobile Home Park, Cannon Road Alignment 1 39 17: Modeled receiver locations and proposed noise barriers, Rancho Carlsbad Mobile Home Park, Cannon Road AUgnment 2 40 18: Modeled receiver locations - garden 43 19: Modeled receiver locations and proposed noise barriers - Robertson Ranch house 46 TABLES 1: Year 2020 Roadway Traffic Parameters 13 2: Average Noise Levels of Rock Processing Plants at a Distance of 50 Feet 22 3: Materials Processing, Distance to Noise Contours 23 4: Future Projected Noise Levels - Village H 27 5: Future Projected Noise Levels - Village K 31 6: Future Projected Noise Levels - Village U 34 7: Future Projected Noise Levels - Villages W, X, and Y 37 8: Future Projected Noise Levels, Rancho Carlsbad Mobile Home Park, Cannon Road - Alignment 1 41 9: Future Projected Noise Levels, Rancho Carlsbad Mobile Home Park, Cannon Road - Alignment 2 42 10: Future Projected Noise Levels, Garden 45 11: Future Projected Noise Levels, Robertson Ranch House 47 12: Distance to Noise Contours, Off-Site Cannon Road and College Boulevard 49 13: Ground-Floor Future Noise Levels, Barrier Heights Limited to Six Feet 54 TABLE OF CONTENTS (cont.) ATTACHMENTS 1 2 3 4 5 6: STAMINA input and output - Village H STAMINA and OPTIMA input and output STAMINA and OPTIMA input and output STAMINA and OPTIMA input and output STAMINA and OPTIMA input and output and Robertson Ranch House STAMINA and OPTIMA input and output of Cannon Road and College Boulevard - Village K - Villages U and W - Villages X and Y - Rancho Carlsbad Mobile Home Park Garden Southeast of Future Intersection Summary The Calavera Hills Master Plan project is located in the city of Carlsbad in the vicinity of future College Boulevard and Carlsbad Village Diive. This report summarizes the potential acoustical impacts due to constmction and implementation of the Calavera Hills Master Plan Phase n. Also included is an acoustical assessment of the proposed off-site extensions of College Boulevard and Cannon Road as provided by the formation of Bridge and Thoroughfare District Number 4 by the City of Carlsbad. Two alignments have been chosen for analysis for both College Boulevard and Cannon Road. With the limitations discussed below, this acoustical assessment addresses the two aUgnments for each roadway. A. Blasting Portions of existing residential developments (Villages C, D, L-l, O, P-1, and Q) could experience noise levels in excess of County standards during blasting activities. Due to the conservative assumptions in the analysis and the fact that blasting would occur adjacent to residential areas temporarily, impacts, although intmsive, are not considered significant. The City of Carlsbad requires that a blasting report be submitted to the City Engineer prior to any blasting activities. The report shall conform to the San Diego County Blasting Ordinance (Division 5, Title 3, Section 35) and vibration standards promulgated by the U.S. Bureau of Mines. Some of the requirements stated in the County ordinance that will lessen potential impacts to existing residential areas and to be incorporated in this project include: 1. Prior to blasting, a blasting schedule shall be approved by the City Engineer. 2. The property owner shall give a one-time notice in writing to residences and businesses within 600 feet of a potential major blast location. 3. The hours of blasting will be from 9:00 A.M. to 4:30 P.M. or one-half hour before sunset, whichever comes first, Monday through Friday. No blasting will be aUowed on weekends or hoUdays. B. Grading Portions of existing residential developments (Villages C, D, E-2, F, G, L-l, Q, and T) and the neighborhood park west of Village E-1 could experience noise levels in excess of County standards. Due to the conservative assumptions in the analysis and the fact that grading would occur adjacent to residential areas temporarily, impacts, although intmsive, are not considered significant. The following measures will reduce the nuisance noise generated by constmction activities: 1. Hours of construction shall be limited to the time period allowed in the Carlsbad Municipal Code, 7:00 A.M. to sunset on weekdays and 8:00 A.M. to sunset on Saturdays. No constmction, except in the event of an emergency, shall occur on Sundays and designated hoUdays. 2. Construction equipment shall be properly maintained and fitted with standard mufflers. C. Materials Processing Centers Noise impacts in the existing residential areas due to materials processing are not anticipated to exceed the City's standards and, consequently, are not considered significant. No mitigation is required. Noise levels are anticipated to exceed 65 dB(A) in portions of Villages C, L-l, O, P-1, and Q. Although these noise levels are below the City's standards for construction activities, given the extended duration of the work (5 to 18 months) these noise levels could result in unmitigated nuisance noise impacts to existing residences during the daytime hours. D. Future Traffic Generated Noise 1. On-Site This on-site analysis is based on the sheet grading provided for each of the viUages in the Master Plan area, as well as the proposed grading for Alignment 1 of College Boulevard, and Alignments 1 and 2 of Cannon Road. If final grading for the villages changes from that analyzed here, the required barrier heights could differ from those indicated below. AUgnment 2 for College Road is proposed as an alternative to Alignment 1. This aUgnment would pass through Villages U and W to the east of Alignment 1. However, no on-site grading within the villages is available for Alignment 2. Consequently, this analysis only considers the acoustical impacts resulting from the implementation of College Boulevard Alignment 1. If Alignment 2 were implemented, detailed acoustical analyses would be required to assess the impacts of College Boulevard AUgnment 2 on the sunounding on-site land uses. Off-site impacts for these altematives are discussed below. Noise levels are projected to exceed the City's residential exterior noise standard of 60 community noise equivalent level (CNEL) adjacent to the roadways in Villages E-1, K, U, W, X, and Y. Noise levels are projected to exceed the City's exterior noise standard for schools of 60 CNEL in Village H. Noise levels are projected to remain below 60 CNEL on Villages L-2 and R. Constmction of noise barriers with the following heights will reduce on-site noise levels to 60 CNEL or less: Village E-1 barrier height varying from 8 to 11 feet Village H barrier height varying from 3 to 4 feet Village K barrier height varying from 3 to 5 feet Village U barrier height varying from 5 to 12 feet Village W barrier height varying from 5 to 11 feet Village X barrier height varying from 5 to 9 feet ViUage Y barrier height varying from 6 to 10 feet As indicated, noise barrier heights in excess of six feet are required on Villages E-1, U, W, X, and Y. Barrier heights may be accomplished through the construction of walls, berms, or a combination of both. Nevertheless, it is a poUcy of the City of Carlsbad to discourage the use of walls in excess of six feet adjacent to circulation element roadways. If noise barriers are limited to six feet in height, noise levels adjacent to the roadways on Villages E-1, U, W, X, and Y would be projected to exceed 60 CNEL after barrier constmction. In light of the City's desire to limit walls along circulation element roadways to six feet or less, the City's General Plan requires that: all purchasers of the impacted property shall be notified in writing prior to purchase, and by deed disclosure in writing, that the property they are purchasing is, or will be, noise impacted and does not meet Carlsbad noise standards for residential property. Consequently, if noise baiiier heights are to be Umited to six feet, future purchasers within the developments adjacent to the roadways (ViUages E-1, U, W, X, and Y) would require notification indicating that they are purchasing noise-impacted property. With the inclusion of notification and the constmction of barriers, noise impacts would be adequately mitigated. Even with the constmction of noise barriers, noise levels at the second floors of the residential units adjacent to the roadways in ViUages E-1, K, U, W, X, and Y are projected to exceed 65 CNEL. Therefore, standard construction is not assumed to adequately reduce interior noise levels to below 45 CNEL at these locations. At the time that building plans are available for these units, and prior to the issuance of building permits, a detailed acoustical analysis will be required ensuring that second-floor interior noise levels due to exterior sources will be below the 45 CNEL interior standard. Additionally, if noise barriers are limited to six feet in height, noise levels at the first floors also could exceed 60 CNEL, and in some cases could exceed 65 CNEL. For those areas where ground- and/or second-floor exterior noise levels are projected to exceed 60 CNEL, it will be necessary for the windows to remain closed to ensure that interior noise levels meet the City's interior standard of 45 CNEL. The building code and the City of Carlsbad require that for areas in excess of 60 CNEL where it is necessary to keep windows closed, forced-air circulation or air conditioning be provided. The affected units would be the units adjacent to the roadways. If first-floor noise levels are projected to exceed 65 CNEL, the required interior acoustical studies must also consider those first- floor rooms. 2.0ff-Site Cannon Road/College Boulevard If future sensitive receivers are placed within approximately 1,500 feet of the roadway aUgnments, potentially significant noise impacts could occur. Consequently, any new development placed adjacent to these roadways shall be required to prepare detailed acoustical studies that demonstrate that on-site noise levels will meet City standards. Rancho Carlsbad Mobile Home Park Exterior noise levels in the northwestern and northeastem portions of the mobile home park are anticipated to exceed the City's 60 CNEL residential standard for both proposed alignments of Cannon Road. With the construction of four-foot-high noise barriers along portions of the edge of Cannon Road and College Boulevard, noise levels at all ground- floor usable areas within the mobile home park would be at or below 60 CNEL. Garden Southeast of Future Intersection of Cannon Road and College Boulevard Future noise levels are projected to remain below the City's 70 CNEL exterior standard for agricultural uses. No mitigation is required. Robertson Ranch House Exterior noise levels at the ranch house due to traffic on Cannon Road Alignment 1 are projected to exceed 60 CNEL. With the constmction of noise barriers varying from seven to nine feet in height, exterior noise levels at the ranch house are anticipated to remain at or below the City's 60 CNEL standard. Noise levels at the ranch house property associated with Cannon Road Alignment 2 are anticipated to remain below the 60 CNEL standard. No mitigation is required for this alignment. Church - City of Oceanside Noise levels at the church due to changes in the existing Cannon Road alignment are projected to increase by approximately 1 decibel. Noise level changes of less than 3 decibels in the outdoor environment generally are not perceptible. Additionally, the City of Oceanside does not specify exterior noise level standards for churches. Noise levels at the residences along the south side of the street are anticipated to decrease by the same amount as a result of the roadway realignment. No mitigation is required. Introduction The Calavera Hills Master Plan project is located in the city of Carlsbad in the vicinity of College Boulevard and Carlsbad Village Drive. Figure 1 shows the regional location of the project. Figure 2 shows the project vicinity in the city of Carlsbad as well as the proposed alignments 1 and 2 for both Cannon Road and College Boulevard. Figure 3 shows the layout of the villages within the Master Plan, as well as College Boulevard Alignment 1 . Figure 4 is an aerial photograph of the Master Plan area. This report summarizes the acoustical impacts associated with implementation of the Calavera Hills Master Plan Phase II. Also included is an acoustical assessment of the proposed off-site extensions of College Boulevard and Cannon Road as provided by the fomiation of Bridge and Thoroughfare District Number 4 by the City of Carlsbad. Two alignments have been chosen for analysis for both College Boulevard and Cannon Road. Oceanside PROJECT LOCATION Carlsbad ^~^K^\ San Marcos df Enciitas r 0 t 0 MILES 2 FIGURE 1 Regional Location ofthe Project OCEANSIDE CARLSBAD 0 Source: Plarming Systems 1999 t No Scale Alignment 1 Alignment 2 R-3225e FIGURE 2 Project Vicinity Map PHASE II 0 Source: Planning Systems 1999 No Scale t R-3225e FIGURE 3 Villages Affected by the Calavera Hills Master Plan Amendment 0 Date ot" Photograph: Fcbnuiiy, 2000 t No Scale FIGURE 4 Aerial Photograph of the Project Site With the limitations discussed below, this acoustical assessment addresses the two aUgnments for each roadway. The proposed Calavera Hills Master Plan Phase fl would modify existing land use designations and reanange residential densities to provide for the residential buildout of Villages K, L-2, R, U, W, X, and Y. The designated land use of Village H is PubUc Facility or School. Bridge and Thoroughfare District Number 4 would provide for the extension of Cannon Road from El Camino Real to the Oceanside city boundary, and for the extension of College Boulevard from El Camino Real to Carlsbad Village Drive (formerly Elm Street). This report analyzes impacts to proposed and existing residential and other uses from future traffic noise generated on the adjacent roadways, as well as interim construction noise impacts. Impacts are assessed in accordance with the guidehnes, policies, and standards established by the City of Carlsbad. Measures are recommended, as required, to reduce significant impacts to noise-sensitive areas. The analysis is based on traffic figures provided by the project traffic engineer for the year 2020. Analysis Methodology A. Applicable Standards and Definitions of Terms The CNEL is a 24-hour A-weighted average sound level [dB(A) L^J from midnight to midnight obtained after the addition of 5 dB to sound levels occurring between 7:00 P.M. and 10:00 P.M. and of 10 dB to the sound levels occuning between 10:00 P.M. and 7:00 A.M. A-weighting is a frequency conection that often conelates well with the subjective response of humans to noise. Adding 5 dB and 10 dB to the evening and nighttime hours, respectively, accounts for the added sensitivity of humans to noise during these time periods. Traffic Noise Traffic noise impacts to future sensitive receivers were evaluated in relation to the noise level standards promulgated in the City of Carlsbad's adopted General Plan Noise Element. The noise element of the City of Carlsbad states (City of Carlsbad 1994): Policy C.5: . . . sixty (60) dBA CNEL is the exterior noise level to which all residential units should be mitigated. 65 dBA CNEL is the maximum noise level to which residential units subject to noise from McClellan- 10 Palomar Airport should be permitted. Additional disclosure actions (easements, deed restrictions, recorded notice, etc.) may be required of developer/sellers of noise impacted residential units. Interior noise levels should be mitigated to 45 dBA CNEL when openings to the exterior of the residence are open or closed. If openings are required to be closed to meet the interior noise standard, then mechanical ventilation shall be provided. If a project is approved with exterior noise levels exceeding the level allowable pursuant to this poUcy, all purchasers of the impacted property shall be notified in writing prior to purchase, and by deed disclosure in writing, that the property they are purchasing is, or will be, noise impacted and does not meet Carlsbad noise standards for residential property. Policy C.9: Discourage the exclusive use of noise walls in excess of 6 feet in height as mitigation for noise along Circulation Element roadways. The City's exterior noise standard for agricultural areas, which is assumed to include outdoor garden areas, is 70 CNEL (City of Carlsbad 1995). The City's exterior noise standard for a school site is 60 CNEL and is applied to Village H (City of Carlsbad 1995). Standard construction techniques will provide a 20-decibel reduction of exterior noise levels to an interior receiver when the windows and doors are closed. With these criteria, standard construction could be assumed to result in interior noise levels of 45 CNEL or less when exterior noise levels are 65 CNEL or less. When exterior noise levels are greater than 65 CNEL, consideration of specific constmction techniques is required to ensure that interior noise levels will not exceed the 45 CNEL standard. Construction Noise The section of the City's cunent noise ordinance that addresses construction activities (Section 8.48.010) does not set a noise level standard, but simply limits the hours of construction. The City does not cunently have a noise level standard for constmction noise. Therefore, as established in the Final Environmental Impact Report for the Calavera Hillls Master Plan (EIR 90-5), the significance of the constmction noise produced during project development was assessed in accordance with the County of San Diego Noise Ordinance. San Diego County Noise Ordinance Section 36.410 states that construction noise shall not exceed 75 dB for more than 8 hours during any 24-hour period. 11 The City of Carlsbad does impose time constraints on grading and constmction operations in Carlsbad Municipal Code Section 8.48.010. This ordinance limits grading and constmction operations to the hours of 7:00 A.M. to sunset on weekdays and 8:00 A.M. to sunset on Saturdays. Constmction activities are prohibited on Sundays and holidays. Constmction noise impacts to existing residential neighborhoods were assessed in accordance with the policies stated above. B. Traffic Noise Analysis 1. Traffic Parameters Table 1 presents the future traffic parameters used in this analysis. Future traffic volumes for the roadways in the vicinity of the project were obtained from the project traffic report (Urban Systems Associates 2000). Both Cannon Road and College Boulevard are designated as 4-lane major arterials. Carlsbad Village Drive is designated a 4-lane secondary arterial. The average traffic speed assumed for College Boulevard and Cannon Road was 50 mph. The average traffic speed assumed for Carlsbad Village Drive was 45 mph. The traffic mix used for Carlsbad Village Drive was based on the mix for non-truck routes used in the city of Carlsbad (City of Carlsbad 1995). The traffic mix used for Cannon Road and College Boulevard was based on the mix for designated truck routes in the city of Carlsbad. These mixes were developed through field surveys of routes in Carlsbad (City of Carlsbad 1995). The day, evening, and nighttime traffic distribution was assumed to be 77 percent, 10 percent, and 13 percent, respectively. With these assumptions, the CNEL due to traffic is approximately two decibels above the average daytime hourly equivalent noise level. 2. Analysis of Traffic Noise Noise generated by future traffic was projected using the STAMINA 2.0/OPTIMA computer models from Vanderbilt University (1991). These models are computerized versions of the Federal Highway Administration Noise Prediction Model (1979), which uses California vehicle noise emission levels (California Department of Transportation 1983). Exterior traffic noise levels to first- and second-floor receivers were calculated where necessary. First-floor receivers were placed at five feet above ground level; second-floor receivers were placed at 15 feet above ground level. Calculations were completed for a 12 TABLE I YEAR 2020 ROADWAY TRAFFIC PARAMETERS Roadway ADT Percent Autos Percent Medium Trucks Percent Speed Heavy Trucks (mph) Carlsbad Village Drive Between Pontiac Dr. & Tamarack Ave. 3,000 97.89 Between Tamarack Ave. & College 17,000 97.89 College Boulevard Between El Camino Real & Cannon Rd. 22,000 95.24 Between Cannon Rd. & Carlsbad Village Dr. 24,000 95.24 Between Carisbad Village Dr. & Lake Blvd. 39,000 95.24 Cannon Road Between El Camino Real & College Blvd. 21,000 95.24 Between College Blvd. & Oceanside City Limit 24,000 95.24 Between Oceanside City Limit & MeUose Dr. 30,000 95.24 1.83 1.83 3.52 3.52 3.52 3.52 3.52 3.52 0.28 0.28 1.24 1.24 1.24 1.24 1.24 1.24 45 45 50 50 50 50 50 50 mph = miles per hour daytime hour, and the resulting hourly L^^s were weighted and combined into CNEL values. Projected CNEL values based on the traffic distributions used here are approximately two decibels higher than the daytime hourly L^^ calculated by STAMINA as indicated above. The STAMINA program calculates noise levels at selected receiver locations using input parameter estimates such as projected hourly average traffic rates; vehicle mix, distribution, and speed; roadway lengths and gradients; distances between sources, barriers, and receivers; and shielding provided by intervening tenain, barriers, and stmctures. The OPTIMA model calculates noise levels at selected receivers for varying noise barrier heights using the STAMINA output. Receivers, roadways, and barriers are input into the STAMINA model using three- dimensional coordinates. Grading for the villages and roadways were obtained in the form of computer aided design (CAD) drawings from the project engineers. The Y-axis pointed north and the X- axis pointed east. The STAMINA model allows the user to choose between acoustically "hard" and "soft" site conditions. Hard sites have an attenuation of 3 dB for every doubling of distance from a Une source; soft sites have an attenuation of 4.5 dB for every doubling of distance. Hard site conditions are generally appropriate for all situations except where: The height of the line-of-sight [between the source and receiver] is less than 3 meters, and The view of the roadway is intermpted by isolated buildings, clumps of bushes, scattered trees, or the intervening ground is soft or covered with vegetation (FHWA 1979). Under those situations, soft site conditions may be assumed. Given the topography generally found in this project, hard site conditions were assumed for the prediction of future noise levels. Existing Conditions The majority of the existing Master Plan area has either been built or graded. Agricultural operations cunently exist south and southeast of the Master Plan area encompassing much of the proposed extensions of College Boulevard and Cannon Road. Carlsbad ViUage Drive has been constructed to College Boulevard. College Boulevard has been 14 partially constructed north of Carlsbad Village Drive, but not to the south of Carlsbad Village Drive. There is cunently minimal traffic on these roadways. Future Acoustical Environment and Impacts A. Blasting The areas of non-rippable rock that would need to be blasted are shown in Figure 5. The number and schedule of blasts for each area is not available at this time. Data on noise levels produced by drilling and blasting activities were obtained from a report prepared by RECON in 1986 for the Prohoroff Ranch property in San Marcos, CaUfornia (RECON 1986). As part of this 1986 study, field measurements were taken of blasting activities. Blasting activities can be divided into two separate components: drilling and actual blasting. Holes are drilled into the rock to create areas to place the explosives. These holes are drilled at depths generally ranging from 10 to 28 feet deep. The diameter of the holes will vary, depending on site conditions and distances to structures. For the Prohoroff Ranch project site evaluated in the 1986 RECON study, a series of 20 to 60 holes were drilled for each blast. An IngersoU-Rand V-8 diesel powered air compressor mounted on a trailer drove pneumatic drilling equipment mounted on a tractor. This type of equipment is typically used for drilling. The drilling contractor completed a total of 45 holes in three locations in three days. Field measurements were taken 50 feet from the drilling operation, and the resulting measured average noise level was 89 dB(A) L.^. DrilUng can be expected to occur several days per week. The drilled holes are then filled with explosives. These are electronically detonated in a programmed sequence with millisecond delay times between each detonation. The whole sequence lasts up to one-half second. This pattem causes the rock to fracture in a controlled manner. Because of the detonation sequencing, these blasts have an indistinct rumbling sound that is hard to distinguish from background noise (RECON 1986). Prior to and after a blast, air horn warning signals are sounded. Prior to a blast, the warning signals consist of repeated bursts of the horn. After a blast, the all-clear signal is a continuous burst of the air horn for about 10 seconds. These waming signals are the loudest part of the blasting event. In the 1986 study, noise levels produced by test blasts on the Prohoroff Ranch site were monitored. At one measurement location, there was a clear line of sight to the blast area about 1,870 feet away. A maximum noise level of 71 dB(A) was recorded at the measurement location during the air horn warning signals that were sounded both before and after the actual blast (RECON 1986). 15 I I u dv-d~ v t Potential blasting area 75 dBA Leq contour (275 feet from blasting area) FIGURES 0 Feet 1000 ^ Potential Blasting Areas and 2000 Potential Blast Noise Impact Areas M:\jobs\3225n\gis\noise.apr\fig5 Attenuation of noise from a point source is evaluated using the following equation: A =^0 --^log log- where LQ = Noise level at distance D^, from the noise source L, = Noise level at distance D, from the noise source a = Noise attenuation for every doubUng of distance from a point source Using a standard 6 dB(A) attenuation for every doubling of distance (a) from a point source (Bolt, Beranek, and Newman, Inc. 1973), the resulting noise level produced by the air horn at 50 feet would be approximately 102 dB(A). As a worst case, it was assumed that the air horn would be sounded for a total of approximately 30 seconds during an hour while drilling would occur the remainder of the hour. This is conservative because it assumes that drilling would occur immediately before and after the air horn is sounded and does not consider the explosion time, when noise would be negligible. Using these assumptions, the combined average hourly L^^ of 30 seconds of air horn (102 dB[A]) and 59.5 minutes of drilling (89 dB[A]) results in a noise level of approximately 89.6 dB(A) at 50 feet from the source. This is taken to be the equivalent hourly L^ at 50 feet due to the blasting operations. The distance required to attenuate 89.6 dB(A) to 75 dB(A) is approximately 275 feet. Therefore, any sensitive receivers located within 275 feet of a blasting area and having a clear line of site could experience hourly average noise levels in excess of 75 dB(A). As seen in Figure 5, noise levels could exceed 75 dB(A) L^.^ at existing residential areas in portions of Villages C, D, L-l, O, P-1, and Q while the adjacent villages are being graded. As indicated above, the significance of the construction noise produced during project development was assessed in accordance with the County of San Diego Noise Ordinance. County standards specify that construction noise shall not exceed 75 dB(A) for more than eight hours in any 24-hour period. If blasting activities occur directly adjacent to a residential area within the 75 dB(A) L^^ Une for more than eight hours in any 24-hour period, then noise levels at the adjacent residential area would exceed County standards. 17 B. Grading Grading activities would occur at the proposed villages and also along the proposed alignments of Cannon Road and College Boulevard that would be built as part of this project. Figure 6 shows the limits of grading for the roadways and villages. Ground- clearing activities for housing and roads in a typical suburban residential area are estimated to generate 83-84 dB(A) L^^ 50 feet from the site of construction (Bolt, Beranek, and Newman, Inc. 1971). This value is based on empirical data on the number and types of equipment at a construction site and their average cycle of operation. A site is assumed to have construction equipment evenly distributed throughout its area. Grading noise generally can be treated a point source and would attenuate at 6 dB(A) for every doubling of distance. Using the equation described in the Blasting section above, a noise level of 84 dB(A) L^^ would attenuate to 75 dB(A) L^^ at approximately 150 feet from the noise source. Figure 6 shows the limits of grading for the village sites. College Boulevard, and Cannon Road. This figure also indicates that areas around the grading sites that could experience noise levels in excess of 75 dB(A) L^^ when grading is occurring in a particular area. As seen in Figure 6, noise levels could exceed 75 dB(A) L^^ at existing residential areas in portions of Villages C, D, E-2, F, G, L-l, Q, and T while the adjacent villages are being graded. This includes portions of the park west of Village E-1. Additionally, potential grading noise impacts could occur in limited portion of the Rancho Carlsbad Mobile Home Park during constmction of Cannon Road, particularly if the southern roadway alignment is chosen. Grading noise impacts are also anticipated to occur at the Robertson Ranch house north of the mobile home park during construction of Cannon Road. As indicated above, the significance of the construction noise produced during project development was assessed in accordance with the County of San Diego Noise Ordinance. County standards specify that construction noise shall not exceed 75 dB(A) for more than eight hours in any 24-hour period. If grading occurs directly adjacent to a residential area within the 75 dB(A) L^^ line for more than eight hours in any 24-hour period, then noise levels at the adjacent residential area would exceed County standards. C. Materials Processing Centers Noise associated with operations at the materials processing center (Figure 7) will result from trucks delivering raw material, tmcks departing with processed material, on-site material handling, and raw material crushing operations. Maximum noise levels will occur during raw material crushing operations. A portable crushing and screening unit, and associated equipment, are used for raw material 18 Graded area 75 dBA Leq contour (150 feet from graded area) 2000 4000 FIGURE 6 Limits of Grading and Potential Construction Noise Impact Area M:\jobs\3225n\gis\noise.apr\fig6 i t FIGURE 7 Material processing area I I 75 dBA Leq contour (225 feet from material processing area) ' 65 dBA Leq conlour (713 feet from material processing area) Materials Processing Areas Qo and Potential Noise Impact Areas 0 Feet 1000 M:\jobs^3225n\gis^noisc.apr\tlg7 processing. A noise survey of the portable cmshing equipment used by South Coast Materials was made in 1994 (Boelter Environmental Consultants 1994). This equipment is considered representative of the equipment to be used in this project. Based on the information obtained during this survey, noise levels due to the cmshing operation are between 87 and 89 dB(A) at 50 feet from the noise source, which is approximately the center of the processing plant. Results of the survey, as well as a study prepared for another rock-cmshing operation (RECON 1988), also indicate that stockpiles of aggregate provide some shielding and that added noise from the conveyor belts and falling aggregate do not appreciably increase the overall noise levels. Table 2 summarizes the results of noise measurements at several other portable process- ing plants which crush and screen hard rock with equipment similar to that proposed for this project (RECON 1988; RECON 1998). The results in Table 2 have been standardized to a distance of 50 feet from the noise source to allow comparison. The noise source was assumed to behave as a point source and the attenuation equation described above was used for making the distance adjustments. InaU cases, the noise levels are between 85 and 89 dB(A) at 50 feet from the noise source (RECON 1988). Therefore, a worst-case noise level of 89 dB(A) at 50 feet from the noise source (as determined from the Boelter noise survey) was assumed for the portable crushing equipment to be used by this project (RECON 1998). These noise levels only occur when the unit is actually cmshing material. Results of the noise survey indicate that noise levels may be more than 10 decibels less when the equipment is operating but material is not being cmshed (Boelter Environmental Consultants 1994). Raw material is typically fed to the cmshing unit by a skip loader. After the skip loader has dumped its load into the crusher, it must return to the raw materials pile, pick up a load, and travel back to the crushing system. Therefore, it is assumed that during an average hour, the crushing unit is actually crushing material approximately 85 percent of the time. Based on this assumption, the average hourly source noise level for the cmshing system was assumed to be 88 dB(A) L^^ at 50 feet from the noise source. Using this source level, and neglecting any attenuation provided by the aggregate piles. Table 3 shows the distance from the crushing unit to various hourly average noise levels. As seen from Table 3, a worst-case average hourly noise level of 75 dB(A) L^^ would occur at approximately 225 feet from the crushing unit. 21 TABLE 2 AVERAGE NOISE LEVELS OF ROCK PROCESSING PLANTS AT A DISTANCE OF 50 FEET Equipment L at 50 Feet [dB(A)] Reference Portable rock cmshing plant 85 Bricken 1984:Exhibit 3 Portable crushing and screening plant 87 San Diego Acoustics 1986a:2 (based on measured 76 dB(A) at 180 feet) Portable cmshing and screening plant 89 San Diego Acoustics 1986b:2 (based on measured 75 dB(A) at 250 feet) SOURCE: RECON 1988. TABLE 3 MATERIALS PROCESSING DISTANCE TO NOISE CONTOURS (feet from crushing unit) Noise Level [dB(A) L^J Distance 88 50 85 71 80 125 75 225 70 400 65 713 Figure 7 shows the proposed layout of the materials processing sites. As seen from this figure, material processing centers are planned for Villages K, W, and X. It is anticipated that the processing area in Village K will operate for about five months. The processing areas in Villages W and X will not operate simultaneously and it is anticipated that they will be in operation for a cumulative total of 18 months. As indicated in Table 3, the 75 dB(A) contour resulting from the material processing operations would lie approximately 225 feet from the processing area. These noise levels would only occur during the daytime operating hours as specified by the County's noise ordinance. From Figure 7 it is seen that the 75 dB(A) noise contours due to the processing operations are anticipated to remain outside of the existing residential areas. Consequently, no significant noise impacts due to the materials processing centers are anticipated. Nevertheless, as seen in Figure 7, noise levels are anticipated to exceed 65 dB(A) in portions of Villages C, L-l, O, P-1, and Q. Although these noise levels are below the City's standards for construction activities, given the extended duration of the work (5 to 18 months) these noise levels could represent a nuisance during the daytime hours to existing residential areas in those villages. D. Future Traffic Generated Noise The methods used in the analysis of future conditions are described in the Analysis Methodology section of this report. The traffic parameters used are shown in Table 1. 23 1. On-Site Noise levels were modeled for a series of receivers located in each village area as required to determine the future noise levels due to traffic on the area roadways. The on-site analysis discussed below is based on the sheet grading provided for each of the villages in the Master Plan area, as well as the proposed grading for Ahgnment 1 of College Boulevard, and Alignments 1 and 2 of Cannon Road. If final grading for the villages changes from that analyzed here, the required barrier heights could differ from those indicated below. Alignment 2 for College Road is proposed as an altemative to Alignment 1. This alignment would pass through Villages U and W to the east of AUgnment 1. However, no on-site grading within the villages is available for Align- ment 2. Consequently, this analysis only considers the acoustical impacts resulting from the implementation of College Boulevard Alignment 1. If Alignment 2 were imple- mented, detailed acoustical analyses would be required to assess the impacts of College Boulevard Alignment 2 on the sunounding on-site land uses. Off-site impacts for these alternatives are discussed below. Village H This village is proposed for either Public Facility or School development (see Figure 3). As indicated above, the exterior noise standard applied to this Village is 60 CNEL. Noise levels were modeled for a series of receivers located in the proposed development area of Village H. The resulting ground floor noise contours are plotted in Figure 8. As seen from Figure 8, noise levels are projected to exceed the 60-CNEL exterior standard adjacent to Carlsbad Village Drive. Noise levels were also modeled at 10 receiver locations as shown in Figure 9. The resulting noise levels at the first and second floors of these locations are shown in Table 4. STAMINA input and output data are contained in Attachment 1. Village E-1 Detailed grading for this village is not available at this time (see Figure 3). Therefore, flat site conditions were assumed, which will result in worst case predicted noise levels for this site. With these assumptions, the 60 CNEL contour is anticipated to lie approximately 1,100 feet from the centeriine of College Boulevard, and approximately 500 feet from Carlsbad Village Drive. Consequently, future noise levels on this village are anticipated to exceed City standards. Village K This village is proposed for single-family residential development (see Figure 3). Noise levels were modeled for a series of receivers located in the proposed development area of Village K. The resulting ground floor noise contours are plotted on Figure 10. As seen 24 25 t 0 Feet 90 /\y Future noise contours 180 HGURE 8 Projected Future Noise Contours - Village H M:\jobs\3225n\gis\noise.apr\fig8 ft5 9/ 95 91 Hi 25 t 0 Feet 40 HO • Modeled receiver /\y 3 foot high barrier 4 foot high barrier FIGURE 9 Modeled Receiver Locations and Proposed Noise Barriers - Village H M:\JobsV3225n\gis\noise.apr\fig9 TABLE 4 FUTURE PROJECTED NOISE LEVELS - VILLAGE H Receiver Projected Noise Level with No Constmcted Noise Barriers (CNEL) Projected Noise Level with Constmcted Noise Barriers (CNEL) 1 56 55 2 61 58 3 63 59 4 63 60 5 64 59 6 64 59 7 65 60 8 65 60 9 60 57 10 56 55 I fi t Feet 200 M:\j()bs\3225 n\gis\noisc.api\fig 10 400 /\/ Future noise contours FIGURE 10 Projected Future Noise Contours - Village K from Figure 10, noise levels are projected to exceed the 60 CNEL exterior standard in the southern and eastem portions of the development. Noise levels were also modeled at 14 receiver locations as shown in Figure 11. The resulting noise levels at the first and second floors of these locations are shown in Table 5. STAMINA input and output data are contained in Attachment 2. . Village L-2 Village L-2 is proposed for single-family residential development (see Figure 3). This development will be shielded from road noise by sunounding development in Villages D and K. Consequently, noise levels are anticipated to remain below the City's 60 CNEL exterior noise standard. Village R This village is proposed for single-family residential development (see Figure 3). The residential development is located well away from College Boulevard. On-site exterior noise levels are anticipated to remain below the City's 60 CNEL residential exterior noise standard. Village U This village is proposed for single-family residential development (see Figure 3). Noise levels were modeled for a series of receivers located in the proposed development area of Village U. The resulting ground floor noise contours are plotted in Figure 12. As seen from Figure 12, noise levels are projected to exceed the 60 CNEL exterior standard adjacent to College Boulevard. Noise levels were also modeled at 13 receiver locations as shown in Figure 13. The resulting noise levels at the first and second floors of these locations are shown in Table 6. . STAMINA input and output data are contained in Attachment 3. Village W This village is proposed for single-family residential development (see Figure 3). Noise levels were modeled for a series of receivers located in the proposed development area of Village W. The resulting ground floor noise contours are plotted on Figure 14. As seen from Figure 14, noise levels are projected to exceed the 60 CNEL exterior standard adjacent to College Boulevard. Noise levels were also modeled at 14 receiver locations as shown in Figure 15. The resulting noise levels at the first and second floors of these locations are shown in Table 7. STAMINA input and output data are contained in Attachment 3. 29 tm t Feet 200 M:\jobs\3225n\gis\noisc.api\figl I 400 • Modeled receiver 3 foot high hairier 4 foot high barrier /\/ 5 foot high barrier FIGURE 11 Modeled Receiver Locations and Proposed Noise Barriers - Village K TABLE 5 FUTURE PROJECTED NOISE LEVELS - VILLAGE K (CNEL) No Noise Barriers With Noise Barriers Receiver 1st floor 2nd floor 1st floor 2nd floor 1 51 54 51 54 2 58 59 58 59 3 60 60 60 60 4 60 60 60 60 5 60 61 59 61 6 61 61 60 61 7 61 61 60 61 8 61 62 57 62 9 64 65 59 64 10 66 66 60 66 11 66 66 60 66 12 65 66 60 66 13 65 65 59 65 14 60 63 56 61 t 0 Feet 150 300 /\/ Future noise contours FIGURE 12 Projected Future Noise Contours - Village U M:Vjoh.s\3225n\gis\noise.aprVfigl2 t 0 Feet 5 foot high barrier 6 foot high bairier 7 foot high barrier 8 foot high banier ^0 9 foot high barrier 10 foot high bamer 11 foot high barrier 12 foot high barrier Modeled receiver FIGURE 13 Modeled Receiver Locations and Proposed Noise Barriers - Village U M:\jobs\3225n\gis\noise.apr\fig 13 TABLE 6 FUTURE PROJECTED NOISE LEVELS - VILLAGE U (CNEL) No Noise Barriers With Noise Barriers Receiver 1st Floor 2nd Floor 1st Floor 2nd Floor 1 68 72 . 60 66 2 67 70 59 63 3 64 66 58 61 4 64 67 59 63 5 63 64 58 59 6 64 68 59 63 7 63 64 58 60 8 66 68 60 63 9 64 64 59 60 10 66 68 60 63 11 63 64 59 60 12 67 70 60 66 13 75 75 60 73 •pnii -uU \ y\/ Future noise contours t 0 Feet 200 400 FIGURE 14 Projected Future Noise Contours - Villages W, X, and Y M:\ioh.sV3225n\ciMnoi,';e.apr\ric 14 L 0 5 foot high barrier 6 foot high banner 7 foot high ban^ier 8 foot high barrier 9 foot high bairier 10 foot high barrier 11 foot high barrier • Modeled receiver HGURE 15 t I 0 Feet M:\iobsW225n\gi.'i\noise.api\fig 15 200 400 Modeled Receiver Locations and Proposed Noise Barriers - ViUages W, X, and Y TABLE 7 FUTURE PROJECTED NOISE LEVELS - VILLAGES W, X, AND Y (CNEL) No Noise Barriers With Noise Barriers Receiver 1st Floor 2nd Floor 1st Floor 2nd Floor 1 71 72 59 71 2 70 70 59 70 3 71 71 59 71 4 72 72 59 72 5 69 70 60 69 6 71 71 60 71 7 74 74 60 74 8 74 74 60 74 9 72 72 60 72 10 70 71 60 70 11 62 67 59 64 12 65 66 59 64 13 73 • 73 60 73 14 68 70 59 68 15 60 63 57. 61 16 61 62 56 59 17 70 73 60 68 18 65 67 59 61 19 59 61 59 61 20 59 61 58 61 21 62 65 59 62 22 62 63 60 61 23 65 68 60 63 24 64 64 60 61 25 66 71 60 65 26 • 65 66 60 63 27 74 74 60 73 28 66 68 59 66 Village X This village is proposed for single-family residential development (see Figure 3). Noise levels were modeled for a series of receivers located in the proposed development area of Village X. The resulting ground floor noise contours are plotted in Figure 14. As seen from Figure 14, noise levels are projected to exceed the 60 CNEL exterior standard adjacent to College Boulevard. Noise levels were also modeled at six receiver locations as shown in Figure 15. The resulting noise levels at the first and second floors of these locations are shown in Table 7. STAMINA input and output data are contained in Attachment 4. Village Y This village is proposed for multi-family residential development (see Figure 3). Noise levels were modeled for a series of receivers located in the proposed development area of Village Y. The resulting ground floor noise contours are plotted on Figure 14. As seen from Figure 14, noise levels are projected to exceed the 60 CNEL exterior standard adjacent to College Boulevai-d. Noise levels were also modeled at eight receiver locations as shown in Figure 15. The resulting noise levels at the first and second floors of these locations are shown in Table 7. STAMINA input and output data are contained in Attachment 4. 2. Off-Site Rancho Carlsbad Mobile Home Park Future Cannon Road will be built to the north of the Rancho Carlsbad Mobile Home Park. Noise levels were modeled at 21 receiver locations adjacent to and within the mobile home park. These receiver locations are shown in Figures 16 and 17. The analysis includes the effects of the existing approximately five-foot-high wall that runs along the northern boundary of the mobile home park. In the vicinity of the mobile home park. College Boulevard Alignments 1 and 2 are the same. STAMINA input and output data are contained in Attachment 5. Table 8 provides the projected noise levels at these modeled receivers for Alignment 1 of Cannon Road. Table 9 provides the projected noise levels for AUgnment 2. From these tables it can be seen that future projected noise levels within the mobile home park are projected to exceed 60 CNEL in both the northwest and northeast portions of the park. Garden Southeast of Future Intersection of Cannon Road and College Boulevard There is an existing garden located to the southeast of the future intersection of Cannon Road and College Boulevard (see Figure 4). Noise levels were modeled at six receiver locations within the garden ai^ea. These receiver locations are shown in Figure 18. 38 filEO t 0 Feet 300 • Modeled receiver — 4 foot high barrier — Existing mobile home parit wall 600 HGURE 16 Modeled Receiver Locations and Proposed Noise Barriers, Rancho Carlsbad Mobile Home Park, Cannon Road Alignment 1 M:\jobs\3226n\gis\noisc-apr\rigl6 t • Modeled receiver ^— 4 foot high barrier Existing mobile home park wall 0 Feet 300 600 HGURE 17 Modeled Receiver Locations and Proposed Noise Barriers, Rancho Carlsbad Mobile Home Park, Cannon Road Alignment 2 M:\Jobs\3226n\gisVnoise.jpr\rLgl7 TABLE 8 FUTURE PROJECTED NOISE LEVELS RANCHO CARLSBAD MOBILE HOME PARK CANNON ROAD - ALIGNMENT 1 (CNEL) Receiver No Roadway Barriers With Roadway Barriers 1 65 64 2 59 59 3 65 62 4 61 60 5 64 63 6 60 60 7 63 63 8 61 61 9 59 59 11 63 60 12 61 58 13 62 59 14 62 59 15 61 59 16 62 59 17 62 59 18* 61 59 19 62 60 20 60 58 21 59 57 22 57 55 ''Receiver 18 is at the tennis courts. TABLE 9 FUTURE PROJECTED NOISE LEVELS RANCHO CARLSBAD MOBILE HOME PARK CANNON ROAD - ALIGNMENT 2 (CNEL) Receiver No Roadway Barriers With Roadway Barriers 1 65 64 2 59 59 3 65 62 4 61 60 5 64 63 6 60 59 7 60 60 8 59 59 9 58 57 11 56 55 12 55 55 13 58 57 14 58 57 15 61 , 59 16 61 59 17 61 59 18* 61 59 19 62 60 20 60 58 21 58 57 22 55 54 *Receiver 18 is at the tennis courts. E CD t 0 Feet 80 • Modeled receiver 160 FIGURE 18 Modeled Receiver Locations - Garden College Boulevard AUgnments 1 and 2 are essentially the same relative to this garden. STAMINA input and output data are contained in Attachment 6. Table 10 provides the projected noise levels at these modeled receivers for both Alignment 1 and Alignment 2 of Cannon Road. From this table it can be seen that future noise levels within the garden are projected to remain below 70 CNEL, which is the City's exterior noise standard for agricultural uses. Robertson Ranch House Future Cannon Road will be built to the north of the Robertson Ranch House. Noise levels were modeled at six receiver locations adjacent to the house. These receiver locations are shown in Figure 19. College Boulevard is located far enough to the east such that the different College Boulevard aUgnments do not substantially produce different noise levels at the house. STAMINA input and output data are contained in Attachment 5. Table 11 provides the projected noise levels at these modeled receivers for both Alignment 1 and Alignment 2 of Cannon Road. From this table it can be seen that future projected noise levels adjacent to the house are projected to exceed 60 CNEL for AUgnment 1, but will remain below the 60 CNEL residential standard for Alignment 2. Church - City of Oceanside Proposed AUgnment 1 for Cannon Road would reaUgn the westernmost portion of existing Cannon Road in the city of Oceanside. The resulting reaUgnment would straighten the road such that it would be moved slightly closer to the church (approximately 15 feet) and away from the existing residential on the opposite side of the street. The road straightening would also increase the view angle of the roadway from a sensitive receiver at the church by about 20 degrees. These changes in roadway geometry are anticipated to increase exterior noise levels at the church by approximately 1 decibel. A change in exterior noise levels of 3 dB is considered perceptible; changes of less than 3 decibels in general are not noticeable in the outdoor environment (Bolt, Beranek, and Newman 1973:1-20). Therefore, since the projected noise increase is less than 3 decibels at the church, it is not considered a significant direct impact. Noise levels at the existing residential uses on the south side of the street would be anticipated to decrease by a similar amount with this alignment. AUgnment 2 for Cannon Road would also shift the existing aUgnment sUghtly to the north, but by an amount less than that with AUgnment 1. Consequently, noise impacts at the church due to Alignment 2 will be less than those with Alignment 1. 44 TABLE 10 FUTURE PROJECTED NOISE LEVLS GARDEN (CNEL) Receiver Cannon Road AUgnment 1 Cannon Road AUgnment 2 1 63 62 2 61 60 3 59 59 4 63 63 5 60 60 6 58 58 25 t 0 Feet 30 60 • Modeled receiver — 7 foot high barrier — 8 foot high barrier 9 foot high barrier FIGURE 19 Modeled Receiver Locations and Proposed Noise Barriers - Robertson Ranch House TABLE 11 FUTURE PROJECTED NOISE LEVELS ROBERTSON RANCH HOUSE (CNEL) Receiver Cannon Road - Alignment 1 Cannon Road - Alignment 2 Receiver No Barriers With Barriers No Barriers With Barriers 10 71 60 57 NA 23 71 58 57 NA 24 71 56 57 NA- 25 70 60 57 NA 26 72 60 57 NA 27 70 59 57 NA NA = barriers not required for AUgnment 2. Cannon Road/College Boulevard Table 1 indicates the, future projected traffic volumes for these roadways. Table 12 provides the projected distance from the centeriine of the roadway to specified noise contours for the various off-site roadway segments. This table was generated assuming hard site conditions. Using this table it can be seen that, depending on the reach, if future sensitive receivers are placed within approximately 1,500 feet of the roadways, potentially significant noise impacts could occur. Mitigation A. Blasting Portions of existing residential developments (Villages C, D, L-l, O, P-1, and Q) could experience noise levels in excess of County standards during blasting activities. Due to the conservative assumptions in the analysis and the fact that blasting would occur adjacent to residential areas temporarily, impacts, although intrusive, are not considered significant. The City of Carlsbad requires that a blasting report be submitted to the City Engineer prior to any blasting activities. The report shall conform to the San Diego County Blasting Ordinance (Division 5, Titie 3, Section 35) and vibration standards promulgated by the U.S. Bureau of Mines. Some of the requirements stated in the County ordinance that will lessen potential impacts to existing residential areas and to be incorporated in this project include: 1. Prior to blasting, a blasting schedule shall be approved by the City Engineer. 2. The property owner shall give a one-time notice in writing to residences and businesses within 600 feet of a potential major blast location. 3. The hours of blasting will be from 9:00 A.M. to 4:30 P.M. or one-half hour before sunset, whichever comes first, Monday through Friday. No blasting will be allowed on weekends or holidays. B. Grading Portions of existing residential developments (Villages C, D, E-2, F, G, L-l, Q, and T) and the neighborhood park west of Village E-1 could experience noise levels in excess of County standards. Due to the conservative assumptions in the analysis and the fact that 48 TABLE 12 DISTANCE TO NOISE CONTOURS OFF-SITE CANNON ROAD AND COLLEGE BOULEVARD Distance to Contour (feet) Roadway 75 CNEL 70 CNEL 65 CNEL 60 CNEL College Boulevard Between El Camino Real & Cannon Rd. 36 Between Cannon Rd. & Carlsbad Village Dr. 39 Cannon Road Between El Camino Real & College Blvd. 34 Between College Blvd. & Oceanside City 39 Limit Between Oceanside City Limit & Melrose 48 Dr. 112 122 107 122 153 355 387 339 387 484 1123 1225 1072 1225 1531 grading would occur adjacent to residential areas temporarily, impacts, although intmsive, are not considered significant. The following measures will reduce the nuisance noise generated by construction activities: 1. Hours of constmction shall be limited to the time period allowed in the Carlsbad Municipal Code, 7:00 A.M. to sunset on weekdays and 8:00 A.M. to sunset on Saturdays. No constmction, except in the event of an emergency, shall occur on Sundays and designated hoUdays. 2. Constmction equipment shall be properly maintained and fitted with standard mufflers. C. Materials Processing Centers Noise impacts in the existing residential areas due to materials processing are not anticipated to exceed the City's standards and, consequently, are not considered significant. No mitigation is required. Noise levels are anticipated to exceed 65 dB(A) in portions of Villages C, L-l, O, P-1, and Q. Although these noise levels are below the City's standards for construction activities, given the extended duration of the work (5 to 18 months) these noise levels could result in unmitigated nuisance noise impacts to existing residences during the daytime hours. D. Future Traffic Generated Noise Barrier heights specified below are relative to pad elevations where barriers are constructed at the pad edge. Where barriers are constmcted along the roadway edges; the barrier height is relative to the roadway. Required barrier heights may be achieved through the constmction of walls, berms, or wall/berm combinations. The effectiveness of a barrier is dependent upon the quality of constmction and the barrier material mass and acoustical properties. Barriers should be free of cracks and holes. The transmission loss through a barrier should be at least 10 decibels greater than the estimated banier attenuation (Federal Highway Administration 1979:34). If a barrier attenuates noise levels by 5 dB(A) at a receiver location, the barrier transmission loss must be at least 15 dB(A) to prevent audible noise from traveling through the banier and adding to the acoustical environment. Examples of acceptable barrier materials include, but are not Umited to, masoniy block, wood frame with stucco, 0.5-inch-thick Plexiglas, 50 or 0.25-inch-thick plate glass. If transparent barrier materials are used, no gaps should occur between the panels. 1. On-Site Village H As indicated, on-site exterior noise levels adjacent to Carlsbad Village Drive are anticipated to exceed the City's 60 CNEL exterior standard for school uses. With the construction of noise barriers varying from three to four feet in height along the top of the pad slopes as shown in Figure 9, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 4 shows the anticipated noise levels after construction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 1. Village E-1 As indicated, on-site exterior noise levels in the development areas are anticipated to exceed the City's 60 CNEL residential standards. With the construction of noise baniers approximately 11 feet in height along College Boulevard, and 8 feet in height along Carlsbad Village Drive, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Approximately seven-foot-high baniers along College Boulevard and five-foot-high barriers along Carlsbad Village Drive would be required to reduce on-site noise levels to 65 CNEL. Once detailed site grading is available for this village, a detailed acoustical study shall be performed to refine the required barrier heights. Village K As indicated, on-site exterior noise levels in a limited portion of the development area are anticipated to exceed the City's 60 CNEL residential standard. With the constmction of noise barriers varying from three to five feet in height along the top of the pad slopes as shown in Figure 11, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 5 shows the anticipated noise levels after construction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 2. Village L-2 On-site noise levels in the development areas are anticipated to remain below the City's exterior noise standard. No mitigation is required. 51 Village R On-site noise levels in the development areas are anticipated to remain below the City's exterior noise standard. No mitigation is required. Village U As indicated, on-site exterior noise levels in the development areas are anticipated to exceed the City's 60 CNEL residential standard. With the construction of noise barriers varying from five to twelve feet in height along the edge of College Boulevard as shown in Figure 13, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 6 shows the anticipated noise levels after constmction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 3. Additional points of access from College Boulevard have not been clearly delimited in the village design. If additional breaks in the proposed barriers are required, no usable exterior areas shall be placed adjacent to those breaks. Village W As indicated, on-site exterior noise levels in the development areas are anticipated to exceed the City's 60 CNEL residential standard. With the construction of noise barriers varying from five to eleven feet in height along the edge of College Boulevard as shown in Figure 15, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 7 shows the anticipated noise levels after construction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 3. The points of access from College Boulevard have not been clearly delimited in the village design. If breaks in the proposed barriers are required, no usable exterior areas shall be placed adjacent to those breaks. Village X As indicated, on-site exterior noise levels in the development areas are anticipated to exceed the City's 60 CNEL residential standard. With the construction of noise barriers varying from five to nine feet in height along the top of slope as shown in Figure 15, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 7 shows the anticipated noise levels after construction of the proposed noise baniers at the modeled receivers. STAMINA and OPTIMA input and output are contained in Attachment 4. 52 The points of access from College Boulevard have not been cleaiiy delimited in the village design. If breaks in the proposed barriers are required, no usable exterior areas shall be placed adjacent to those breaks. Village Y As indicated, on-site exterior noise levels in the development areas are anticipated to exceed the City's 60 CNEL residential standard. With the constmction of noise barriers varying from six to ten feet in height along the top of slope as shown in Figure 15, noise levels at all ground-floor usable areas within the village would be at or below 60 CNEL. Table 7 shows the anticipated noise levels after construction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 4. The points of access from College Boulevard have not been clearly delimited in the village design. If breaks in the proposed baniers are required, no usable exterior areas shall be placed adjacent to those breaks. Limiting Barrier Heights to Six Feet As indicated previously, it is a poUcy of the City to discourage the use of noise walls in excess of six feet in height adjacent to circulation element roadways. As discussed above, barrier heights in excess of six feet are required on Villages E-1, U, W, X, and Y to reduce exterior noise levels to the City's 60 CNEL exterior residential noise standard. Table 13 provides the results of the noise model when the noise barriers are limited to six feet in height. For Village U on-site noise levels are generally below 65 CNEL except for the extreme northwest comer of the site where noise levels could reach 67 CNEL. On Village W, on-site noise levels are generally below 65 CNEL except for the southwest corner of the upper pad (receiver location 27 on Figure 15). On Village X, on-site noise levels are projected to remain below 65 CNEL. For Village Y, on-site noise levels are projected to remain below 65 CNEL except for the northern portion of the site adjacent to College Boulevard. STAMINA and OPTIMA input and output data are contained in Attachment 3 for Villages U and W, and in Attachment 4 for Villages X and Y. In light of the City's desire to limit walls along circulation element roadways to six feet or less, the City's General Plan requires that "all purchasers of the impacted property shall be notified in writing prior to purchase, and by deed disclosure in writing, that the property they are purchasing is, or will be, noise impacted and does not meet Carlsbad noise standards for residential property" (City of Carlsbad 1994). Consequently, if noise banier heights are to be Umited to six feet, future purchasers within these developments adjacent to the roadways would have to be notified that they 53 TABLE 13 GROUND-FLOOR FUTURE NOISE LEVELS BARRIER HEIGHTS LIMITED TO SIX FEET (CNEL) Receiver Village U (see Figure 12) ViUage W, X, & Y (see Figure 14) 1 62 63 2 62 61 3 60 62 4 59 64 5 58 62 6 59 62 7 59 67 8 61 67 9 59 64 10 61 62 11 59 59 12 63 60 13 67 64 14 NA 62 15 NA 58 16 NA • 58 17 NA, 64 18 NA 61 19 NA 59 20 NA 59 21 NA 59 22 NA 60 23 NA 61 24 " NA 60 25 NA 61 26 NA 61 27 NA 67 28 NA 62 are purchasing noise impacted property. With the inclusion of notification, noise impacts would be adequately mitigated. Interior Noise Levels As seen from Tables 5 through 7, even with the constmction of noise barriers, noise levels at the second floors of the units adjacent to the roadways in Villages E-1, K, U, W, X and Y are projected to exceed 65 CNEL. Therefore, standard constmction is not assumed to adequately reduce interior noise levels to below 45 CNEL at these locations. At the time that building plans are available for the units in these villages, and prior to the issuance of building permits, a detailed acoustical analysis will be required ensuring that second-floor interior noise levels due to exterior sources will be below the 45 CNEL interior standard. Additionally, if noise barriers are limited to six feet in height, noise levels at the first floors also could exceed 60 CNEL. For those areas where ground- and/or second-floor exterior noise levels are projected to exceed 60 CNEL, it will be necessary for the windows to remain closed to ensure that interior noise levels meet the City's interior standard of 45 CNEL. The building code (for multi-family buildings) and the City of Caiisbad require that for residential areas in excess of 60 CNEL where it is necessary to keep windows closed, forced-air circulation or air conditioning be provided. The affected units would be the units adjacent to the roadways. If banier heights are limited to six feet, and units are placed in areas where the ground floor exterior noise levels could exceed 65 CNEL (see discussion above), the interior studies shall also consider the first-floor rooms of the affected units. Site Grading Changes As indicated previously, this analysis is based on the sheet grading provided for each of the villages in the Master Plan area. If final grading for the villages changes from that analyzed here, the required barrier heights could differ from those indicated above. 2. Off-Site Rancho Carlsbad Mobile Home Park As indicated, an existing - approximately five-foot-high wall runs along the northern boundary of the mobile home park. Projected on-site exterior noise levels in the northwestern and northeastern portions of the mobile home park are anticipated to exceed the City's 60 CNEL residential standard for both proposed alignments for Cannon Road. With the construction of four-foot-high noise baniers along the edge of the. roadway as shown in Figure 16 for AUgnment 1, and in Figure 17 for AUgnment 2, noise levels at all ground-floor usable areas within the mobile home park would be at or below 60 CNEL. 55 Tables 9 and 10 show the anticipated noise levels after constmction of the proposed noise baniers at the modeled receivers for Cannon Road AUgnments 1 and 2, respectively. STAMINA and OPTIMA input and output data are contained in Attachment 5. Garden Southeast of Future Intersection of Cannon Road and College Boulevard Future noise levels are projected to remain below the City's 70 CNEL exterior standard for agricultural uses. No mitigation is required. Robertson Ranch House Noise levels at the ranch house due to traffic on Cannon Road Alignment 1 are projected to exceed 60 CNEL. With the construction of noise baniers varying from seven to nine feet in height as shown in Figure 19, exterior noise levels at the ranch house are anticipated to remain at or below the City's 60 CNEL standard. Table 12 shows the anticipated noise levels after constmction of the proposed noise barriers at the modeled receivers. STAMINA and OPTIMA input and output data are contained in Attachment 5. On-site noise levels associated with Cannon Road Alignment 2 are anticipated to remain below the 60 CNEL standard. No mitigation is required for this aUgnment. Church - City of Oceanside Noise level increases at the church due to changes in the existing Cannon Road alignment are projected to increase by approximately one decibel. Noise level changes of less than three decibels in the outdoor environment generally are not perceptible. Additionally, the city of Oceanside does not specify exterior noise level standards for churches. Noise levels at the residences along the south side of the street are anticipated to decrease by the same about due to the roadway realignment. No mitigation is required. Cannon Road/College Boulevard As indicated previously, if future sensitive receivers are placed within approximately 1,500 feet of the roadways, potentially significant noise impacts could occur. Consequently, any new development placed adjacent to these roadways shall be required to prepare detailed acoustical studies that demonstrate that on-site noise levels will meet City standards. 56 References Cited Boelter Environmental Consultants 1994 Aerosol and Noise Survey, Blue Diamond Materials Recycling Facilities, Santa Monica, California, Inglewood, California. Prepared for Southwest Construction Materials & Services, Inc. December 20. Bolt, Beranek, and Newman, Inc. 1971 Noise from Construction Equipment and Operations, Building Equipment, and Home Appliances. EPA Report No. PB-206-717. December. 1973 Fundamentals and Abatement of Highway Traffic Noise. Prepared for the Federal Highway Administration. Report No. PB-222-703. June. CaUfornia Department of Transportation 1983 Califomia Vehicle Noise Emission Levels. Report No. FHWA/CA/Tl-84/13. August. Carisbad, City of 1994 Noise Element. City of Carlsbad General Plan. 1995 Noise Guidelines Manual. September. Federal Highway Administration 1979 Federal Highway Administration Noise Prediction Model. Repoit No. FHWA- RD-77-108, with CaUfornia Vehicle Noise Emissions Levels. Washington, D.C. RECON 1986 An Analysis of Noise Impacts from Drilling and Blasting Operations at the Prohoroff Ranch Property, San Marcos, California. October. 1988 Noise Analysis for Otay Lakes Road Rock Quarry. December 1. 1998 Noise Technical Report for the Concrete and Asphalt RecycUng Facility (Gillespie Field Site), City of El Cajon, CaUfornia. May 28. Urban Systems Associates 2000 Transportation Analysis for Carlsbad Bridge and Thoroughfare District #4. In- house draft. January 17. Vanderbilt University 1991 STAMINA 2.0/OPTIMA Noise Prediction Program. Version 1.2. Prepared by Bowlby and Associates. 57