4.8 NOISE Existing Conditions Background

Transcription

1 4.8 NOISE Existing Conditions Background Sound is mechanical energy transmitted by pressure waves in a compressible medium such as air. Noise is generally defined as unwanted sound. Sound is characterized by various parameters which describe the rate of oscillation of sound waves, the distance between successive troughs or crests, the speed of propagation, and the pressure level or energy content of a given sound wave. In particular, the sound pressure level has become the most common descriptor used to characterize the loudness of an ambient sound level. The unit of sound pressure expressed as a ratio to the faintest sound detectable by a keen human ear is called a decibel (db). Because sound or noise can vary in intensity by over one million times within the range of human hearing, a logarithmic loudness scale similar to the Richter scale used for earthquake magnitude is used to keep sound intensity numbers at a convenient and manageable level. Since the human ear is not equally sensitive to all sound frequencies within the entire spectrum, noise levels at maximum human sensitivity are factored more heavily into sound descriptions in a process called "A-weighting," written as db(a). Any further reference to decibels in this report written as "db" should be understood to be A-weighted values. Decibel levels associated with sound decrease as the distance from the source increases. Sound dissipates exponentially with distance from the noise source. For a point source such as mechanical equipment, sound levels decrease approximately 6 db per doubling of distance from the source. For a line source noise such as traffic, the sound typically decreases three decibels for each doubling of distance. If the site is primarily vegetative which absorbs sound, the rate of dissipation for a line source is four and one-half decibels for each doubling of distance. Time variations in noise exposure are typically expressed in terms of a steady-state energy level equal to the energy content of the time varying period (called Leq), or, alternately, as a statistical description of the sound pressure level that is exceeded over some fraction of a given observation period. Finally, because community receptors are more sensitive to unwanted noise intrusion during the evening and at night, State law requires that, for planning purposes, an artificial db increment be added to quiet time noise levels in a 24-hour noise descriptor called the Community Noise Equivalent Level (CNEL) or Day-Night Noise Level (Ldn). CNEL and Ldn apply a penalty to noise that occurs at night. Noise Standards Exterior and Interior An interior CNEL of 45 db is mandated for residential dwellings in Title 24 of the California Code of Regulations. In 1988, the State Building Standards Commission recommended that the 45 db CNEL interior standard be expanded to include all habitable rooms for all residential occupancy, including single-family. The County of Santa Barbara requires a 45 db(a) Ldn/CNEL interior standard for all residential occupancies. Since typical noise attenuation within residential structures with closed windows is about 20 db, an exterior noise exposure of 65 db CNEL is generally the noise/land use compatibility guideline for new residential dwelling units in California. A 65 db CNEL exterior level is also the noise threshold where noise begins to substantially interfere with enjoyment of any outdoor recreational amenity such as a yard, patio, spa/pool, etc. In the planning of land use in Santa Barbara County, 65 db(a) Ldn/CNEL is regarded as the maximum exterior noise exposure compatible with noisesensitive uses unless noise mitigation features are included in project designs. A level of 65 db(a) CNEL Vital Mission Plan July 2009

2 exterior and 45 db(a) CNEL interior is therefore the applicable noise standard for residential uses adjacent to the Botanic Garden site. On-Site Noise Generation The Santa Barbara noise ordinance contained in the County Code only pertains to loud and unreasonable noise, music, percussion or other sound which is broadcast outside of any residence or building by means of any amplified musical instrument, drum, or similar device, or by means of any radio, loudspeaker, sound amplifier or phonograph, or by means of or employing any similar device which amplifies and produces, reproduces or broadcasts sound during nocturnal hours (after 10 p.m. on weeknights and midnight on weekends). Excluded from this are outdoor gatherings, public dances, shows and sporting and entertaining events, provided such gathering, dance or event is conducted on commercial or institutional premises, pursuant to applicable rules, regulations and zoning restrictions, and in compliance with all permits or licenses issued by a public agency relative to the staging of the gathering, dance or event (Ord. No. 3866, 1). Events at the Botanic Garden would likely be exempt from the regulations. While special events at the Garden may utilize sound amplification devices, on-site activities are not scheduled to go beyond the allowed time limit. Construction Noise For construction activities, the Santa Barbara County Noise Element limits the hours of allowable construction activities. The County of Santa Barbara Environmental Thresholds and Guidelines Manual (Revised October 2006) indicates that construction within 1,600 feet of sensitive receptors should be limited to weekdays (Monday through Friday) between the hours of 8:00 a.m. and 5:00 p.m. Further, the guidelines state that noise attenuation barriers and mufflers of grading equipment may be required for construction equipment generating noise levels above 95 db at 50 feet from the source. Baseline Noise Levels Noise measurements were made in order to document existing baseline levels in the area. These help to serve as a basis for projecting future noise exposure, both from the project upon the surrounding community and from ambient noise activity upon the proposed project. Short-term on-site noise measurements were conducted by Giroux & Associates on Friday, August , and repeated on Saturday August 12, 2006 at 12 on-site locations. The time frame was selected to be consistent with peak project operational hours. The results of the measurements are shown in Table and and the location of the meters is shown in Figure Monitoring experience has shown that 24-hour weighted CNELs are typically 2 to 3 db higher than mid afternoon Leq readings shown in Table This would translate into on-site CNELs of 38 to 57 db. The L 50 noise level represents the median noise level. Half the time the noise level exceeds this level, and half the time it is less than this level. For a relatively constant noise source, the Leq and L 50 are approximately the same. Many of the higher Leq measurements in Table have much lower associated L 50 values. Therefore it is likely that the higher Leq s were due to short term spikes from park visitors conversing directly in front of the noise meter. Vital Mission Plan July 2009

3 Table Short-Term Noise Measurements (db[a]) Friday August 11, 2006 Site Time Leq Lmax Lmin L 1 L 08 L 25 L :53-13: :08-13: :22-13: :38-13: :51-14: :05-14: :26-14: :38-14: :53-15: :08-15: :22-15: :35-15: Site 1: Northernmost bench on Woodland Trail. Site 2: Bench at waterworks/dam exhibit. Site 3: Western most bench on Pritchell Trail. Site 4: Bench, south side of Canyon Trail. Site 5: Bench, Easton Aqueduct Trail, Island Section. Site 6: Bench near Stone Creek Crossing. Site 7: Japanese Tea Garden, front gate. Site 8: Home demonstration garden, Manzanita section. Site 9: Picnic area. Site 10: Under the Oaks section. Site 11: Front kiosk/gate. Site 12: Ceanothus section. Vital Mission Plan July 2009

4 Table Short-Term Noise Measurements (db[a]) Saturday, August 12, 2006 Site Time Leq Lmax Lmin L 1 L 08 L 25 L :55-12: :11-12: :26-12: :44-12: :58-13: :12-13: :26-13: :38-13: :53-14: :05-14: :17-14: :32-14: Site 1: Northernmost bench on Woodland Trail. Site 2: Bench at waterworks/dam exhibit. Site 3: Western most bench on Pritchell Trail. Site 4: Bench, south side of Canyon Trail. Site 5: Bench, Easton Aqueduct Trail, Island Section. Site 6: Bench near Stone Creek Crossing. Site 7: Japanese Tea Garden, front gate. Site 8: Home demonstration garden, Manzanita section. Site 9: Picnic area. Site 10: Under the Oaks section. Site 11: Front kiosk/gate. Site 12: Ceanothus section. Vital Mission Plan July 2009

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6 At the metering site closest to Mission Canyon Road (Site 7), the highest noise readings was 54 db Leq at 1:30 p.m., of which a portion is due to traffic. Site 7 is approximately feet form the Mission Canyon Road centerline. Although noise readings did not coincide with peak traffic volumes along Mission Canyon Road the Traffic Study concludes there are approximately 128 vehicles in the am peak hour and 176 vehicles in the pm peak hour adjacent to the site. This would translate to approximately 60 db Leq at 50 feet from the Mission Canyon Road centerline or db peak Leq at 100 feet from the centerline. The daily flow though Mission Canyon Road is approximately 1,880 vehicles per day. The noise resulting from this traffic is addressed later in this document and was not found to provide a significant noise impact, even at 50 feet from the roadway centerline. Traffic and area ambient noise measured on the project site is not a constraint to development. The highest noise levels were measured at Site 7, closest to Mission Canyon Road and were 54.1 and 42.3 db Leq. Measurements at Site 11, taken by the front gate and parking lot, were 45.9 and 46.7 db Leq on Friday and Saturday respectively. The nearest noise measurements to off-site residences were taken at the project western perimeter, sites 3 and 5. Site 3 is approximately 65 feet to the nearest western property line and Site 5 is approximately 75 feet to the western property line. The highest noise readings on either day for these sites were 40 db Leq and 41 db Leq respectively. Even without adjusting for distance spreading loss to the residential property line, these mid-afternoon noise levels are not very high Thresholds of Significance The County of Santa Barbara Environmental Thresholds and Guidelines Manual (Revised October 2006) states that: a. A proposed development that would generate noise levels in excess of 65 dba CNEL and could affect sensitive receptors would generally be presumed to have a significant impact. b. Outdoor living areas of noise sensitive uses that are subject to noise levels in excess of 65 dba CNEL would generally be presumed to be significantly impacted by ambient noise. A significant impact would also generally occur where interior noise levels cannot be reduced to 45 dba CNEL or less. c. A project will generally have a significant effect on the environment if it will increase substantially the ambient noise levels for noise-sensitive receptors adjoining areas. Per item a., this may generally be presumed when ambient noise levels affecting sensitive receptors are increased to 65 dba CNEL or more. However, a significant effect may also occur when ambient noise levels affecting sensitive receptors increase substantially but remain less than 65 dba CNEL, as determined on a case-by-case level. d. Noise from grading and construction activity within 1,600 feet of sensitive receptors, including schools, residential development, commercial lodging facilities, hospitals or care facilities, would generally result in a potentially significant impact. There are no firm guidelines on what constitutes a substantial increase as per item c, above. In practice, people cannot clearly perceive noise level changes of 3 db or less, particularly if they occur over an extended time period. An increase of more than 3 db, however, requires a doubling of traffic volumes or other source of noise generation over existing conditions. Few projects individually double traffic volumes on already noisy, heavily-traveled streets. Traffic noise impacts in areas already exceeding standards are therefore most often of a cumulative nature rather than individually significant. For the purposes of this analysis, however, an increase of more than 3dB CNEL over ambient noise levels was presumed to result in a significant impact. Vital Mission Plan July 2009

7 4.8.3 Project Impacts 4.8 NOISE The proposed expansion of the Botanic Garden would generate short-term noise during construction and long-term noise associated with project-generated traffic as well as noise generated by events at the Garden. Impacts associated with each of these noise sources are described below. Construction Noise Impacts (Impact N 1) Construction activities, especially operation of heavy equipment, would create short-term noise increases within and near the project site. Temporary construction noise impacts vary markedly because the noise strength of construction equipment ranges widely as a function of the equipment used and its activity level. Short-term construction noise impacts tend to occur in discrete phases dominated initially by earthmoving sources, then by foundation and parking area construction, and finally for finish construction. The potential use of diesel generators to power construction equipment can exacerbate constructionrelated noise. Figure shows the typical range of construction activity noise generation as a function of equipment used in various building phases. The earth-moving sources are the noisiest, with equipment noise ranging up to about 95 db(a) at 50 feet from the source. Spherically radiating point sources of noise emissions are atmospherically attenuated by a factor of 6 db per doubling of distance, or about 20 db in 500 feet of propagation. However, soft site conditions (vegetative rather than concrete) present at the Garden, absorb noise more readily than a typical hard site and accelerate the noise decay rate more than for simple spherical spreading losses. Balancing this acoustic benefit, the unique acoustical amplification of the canyon environment may increase off-site noise. These two effects were presumed to offset each other such that no modification was made to the normal spreading loss assumption. The significance thresholds above indicate that noise from construction activity within 1,600 feet of residential areas would result in the potential for a significant impact. Residences within 1,600 feet of construction areas for proposed project elements are located west of Tunnel Road, east and west of Mission Canyon Road north of the Garden, and north and south of Las Canoas Road. As such construction of the proposed project would result in significant construction-period noise impacts (Impact N 1). Operational Impacts (Impact N 2) Vehicular Noise Impacts The proposed project would generate additional vehicular trips in the project area. Noise generation associated with this increase in vehicular activity was estimated using the California specific vehicle noise curves (CALVENO) in the federal roadway noise model (the FHWA Highway Traffic Noise Prediction Model, FHWA-RD ). The model calculates the Leq noise level for a particular reference set of input conditions, and then makes a series of adjustments for site-specific traffic volumes, distances, roadway speeds, or noise barriers. Table summarizes the 24-hour CNEL level at 50 feet from the roadway centerline along six area roadway segments under existing conditions without the project and existing conditions with the proposed project. As shown on this table, the largest project related noise increase is +1.3 db CNEL at 50 feet from the roadway centerline, which would be experienced by two roadway segments; one on Mission Canyon Road and one on Foothill Road. As discussed above, increases of less than 3 db are not perceptible and are generally not considered to result in a substantial increase in ambient noise. Additionally, the total noise level along each segment at 50 feet from the roadway centerline would be Vital Mission Plan July 2009

8 COMPACTERS (ROLLERS) NOISE LEVEL (dba) at 50 FEET EQUIPMENT POWERED BY INTERNAL COMBUSTION ENGINES STATIONARY MATERIALS HANDLING EARTH MOVING FRONT LOADERS BACKHOES TRACTORS SCRAPERS, GRADERS PAVERS TRUCKS CONCRETE MIXERS CONCRETE PUMPS CRANES (MOVABLE) CRANES (DERRICK) PUMPS GENERATORS COMPRESSORS PNEUMATIC WRENCHES IMPACT EQUIPMENT OTHER JACK HAMMERS & ROCK DRILLS PILE DRIVERS (PEAKS) VIBRATOR SAWS Source: EPA PB , Environmental Protection Agency, Dec , "Noise from Construction Equipment & Operations. SANTA BARBARA BOTANIC GARDEN VITAL MISSION PLAN - FINAL EIR Typical Construction Equipment Noise Generation Levels FIGURE ENVICOM CORPORATION 4.8-2

9 less than the County s 65 db CNEL exterior noise threshold. The proposed project would not create a substantial traffic noise increase, and would not expose any noise-sensitive land uses to noise exceeding County of Santa Barbara noise standards. Therefore, vehicular noise impacts generated by the proposed project would be less than significant. Table Project Traffic Noise Impact Analysis (dba CNEL at 50 feet from centerline) Existing without Project Existing with Project- Generated Traffic Project Contribution Mission Canyon Rd./ S of Foothill N of Foothill N of Tunnel Rd Las Canoas-Site Driveway N of Site Entrance Driveway Foothill Rd./ Mission Canyon between W-E Impacts from On-Site Noise Generation On-site noise generation that may be audible outside the Botanic Garden may derive from several on-site activities. The proposed site is 78 acres. Only 1.45 percent of the site (1.12-acre footprint) would contain facility structures, 4.23 percent (3.34 acres) would contain parking and paved areas, and 3.20 percent (2.54 acres) would contain pathways and paved courtyards. The remaining 91 percent would be open area. As discussed previously, open areas with soft site conditions absorb more sound than typically developed paved areas. It is expected that general attendance to the Botanic Garden in addition to increases in Garden staff would increase by about just over 2 percent per year based on historical visitation growth patterns and proposed increases in staff, classes, and special events. An average of people and 62 staff are currently visits present at the Botanic Garden on a daily basis. The increase of 290 to to 375 daily visitors and staff over the next year (2.25% annual increase) could theoretically create a +0.1 db increase in noise levels (10 * log {296375/290367} = +0.1 db) per year. Over a period of 20 years, a steady 2.25% annual increase (45% over 20 years) in attendance to daily visitors and staff and the associated noise could increase as much as db. The highest on-site hourly noise measurement adjacent to the front gate was 54 db. Per County standards, noise levels are not to exceed 65 dba CNEL at the closest property line. CNEL is a weighted equivalent sound level during a 24 hour day, obtained after addition of five decibels to sound levels in the evening from 7 pm to 10 pm and ten decibels to sound levels at night after 10 pm and before 7 am. If a sound level of (54 db db) db per hour (current maximum hourly plus 20-year growth) was experienced during each operational hour (9 am to 10 pm) the CNEL would be 55 db. Even without adjusting for sound decay due to spreading distance to the nearest property line (6 db per doubling of distance), this increase can be accommodated within the existing noise environment without exceeding noise standards. Therefore, the anticipated increase in general Garden activities is expected to result in an adverse but less than significant noise impact. Vital Mission Plan July 2009

10 The following table demonstrates how hourly Leq noise values would translate into CNEL in the unlikely event that the hourly noise levels were continuous for the Garden s entire operational day (9 am to 10 pm): Hourly Leq (9am to 10 pm) Equivalent Daily CNEL 40 db 39 dba 45 db 44 dba 50 db 49 dba 55 db 54 dba 60 db 59 dba 65 db 64 dba Most classes, docent training and lectures would take place during daytime hours of lesser noise sensitivity; however, increases in attendance at nighttime functions would also occur, as shown in Table 2-4 in Section 2.0 Project Description. Daytime and nighttime classes are the most frequently held event. It is expected that attendance would increase percent and frequency would increase about 10 percent. The annual lecture series is expected to contain the largest change in attendance of all on-site eventsclasses, however there are only seven sessions per year scheduled (no change in frequency proposed). It is not anticipated that a lecture would produce unacceptable noise levels. Likewise, the size of the class groups would likely not alter the noise environment substantially whether there are versus people in attendance and classes would not involve the use of sound amplified equipment. It is anticipated that the future noise level from the classes and lectures would not measurably change the noise environment. Special events were also evaluated for potential noise impacts. Expected changes in attendance and event frequency for these events are provided in Table 2-65 within Section 2.0 Project Description. Of these, private parties would involve evening events that are anticipated to have an attendance increase. Currently people attend these events but this could increase by as much as 2100 people per event. Event occurrence is currently 2-4 times per year but is proposed to increase to eight events per year. Fundraising events are not proposed to increase in attendance but are to increase in frequency from 10 to 15 per year. The private parties are either during the day or between 6 and 10 9 p.m. (with additional time, one hour, for breaking down and cleaning up after events conclude). Noise levels for social functions that involve music can be as loud as 75 db Leq at an assumed reference distance of 50 feet from the music or conversation source. The 75 db Leq assumes use of limited sound amplification; levels above 75 db interfere with the ability for people to converse. Social events where music is so loud such that people cannot carry on a normal conversation are not the types of events that are held at the Garden. The 75 db Leq reference noise level is therefore the maximum level assumed for Garden social events where amplified voice or music might be included. Under line-of-sight conditions, spreading losses without substantial ground absorption would reduce this noise level to 65 db Leq within 150 feet of the activity. It is anticipated that private parties would be held at the Garden facilities within the West of Mission area, which is typically at least 600 feet from the nearest off-site residence. At 600 feet from the source, the noise level would be expected to decay to approximately 53 db. If events were to be held at the Meadow where the closest residence is within 400 feet, the off-site noise level would be approximately 57 db Leq. It is not anticipated that any social event would be held at a location within 150 feet of any off-site residence. Evening social activities are scheduled to end by 10 9 p.m., with additional time allocated for event break down and clean up. For a 3-hour social event ending at 9 p.m., the weighted noise level at the closest homes would range from db CNEL. Such a level would be well below the adopted significance threshold of 65 db CNEL. Although social function noise would be audible at off-site homes because of the low baseline levels in the canyon, given the infrequency of such Vital Mission Plan July 2009

11 events and their termination at 9 p.m. the 65 db CNEL standard is used as the significance threshold for impact assessment.however, even if a social event did not end until 11 pm and the 75 db Leq at 50 feet noise level were constant throughout the entire event (6 pm to 11 pm), the resultant CNEL value would be less than 65 dba at 150 feet from the source. If the social event ended at 10 pm the CNEL would be 62 dba at 150 feet from the source. Again, a doubling of distance would provide for -6 db of noise attenuation, such that a residence 300 feet from the source would experience a CNEL of 56 dba CNEL. It is thus not anticipated that the proposed project would exceed athe significance threshold due to private parties held at the Garden. Therefore, potential noise impacts from private parties are expected to be adverse but less than significant. The parking areas are well away from any off-site residential uses. There are currently 116 marked and unmarked spaces and the proposed project adds three forresults in a total of fully marked and paved spaces. Parking lot noise from moving vehicles is expected to be below applicable noise thresholds at the closest property line. Therefore, potential parking lot noise impacts to off-site receptors are expected to be adverse but less than significant. Non-residential uses require mechanical equipment for heating or air conditioning (HVAC) equipment. The area with the most HVAC equipment, west of Mission Canyon Road, currently has 8 ground mounted heat pumps and is predicted to add 10 ground mounted heat pumps and 4 heat pumps in roof wells. The reference noise level for packaged unit air conditioning is approximately 44 db Leq at 50 feet for a single unit. Although buildings for which the heat pumps will be used are spread out within the west of Mission Canyon Road property, the worst case is assumed to occur if ten (10) units operate simultaneously in the same vicinity for a total Leq of 54 db if a receiver were to have direct-line-of-sight to all 10 units and if all 10 units were a distance of 50 feet from the receiver. It should be noted that 10 units are unlikely to operate simultaneously or in close proximity, and additionally the buildings would shield receptors from a direct line-of-sight to multiple units. Roof mounted units would be recessed in wells which would also provide noise protection such that it is unlikely that a receiver would experience the full 54 db Leq. Nevertheless, the noise from 10 units operating simultaneously decays to 48 db Leq at 100 feet from the source and an additional -6 db for each doubling of distance. If 10 pieces of equipment ran continuously for 4 hours per day the resulting CNEL at 50 feet would be 46 db or 48 db CNEL if the equipment were run 6 hours/day. Even under direct line-of-sight conditions, mechanical equipment would not exceed noise thresholds. Therefore, impacts would be considered adverse but less than significant Cumulative Impacts Traffic Noise Table summarizes the 24-hour CNEL level at 50 feet from the roadway centerline along six area roadway segments under year 2026 conditions without the project and year 2026 conditions with the project. Cumulative area growth, with project implementation, would not cause any significant traffic noise impacts. The largest cumulative traffic noise increase in 2026 with the project as compared to the existing noise level is +1.7 db CNEL on Mission Canyon Road between Las Canoas and the Garden Site Driveway. The project traffic noise contribution along this segment is +1.2 db CNEL. The remainder of the increase (+0.5 db CNEL) is attributed to other projects and area growth. These levels are well below the +3.0 db CNEL criteria for identifying a substantial increase in ambient noise. Therefore, cumulative impacts are adverse but less than significant and the project s contribution would not be cumulatively considerable. Vital Mission Plan July 2009

12 Table Cumulative Traffic Noise Impact Analysis (dba CNEL at 50 feet from centerline) Existing Conditions 2026 without the Project 2026 with Project Cumulative Increase 4.8 NOISE Project Increase Mission Canyon Rd./ S of Foothill N of Foothill N of Tunnel Rd Las Canoas-Site Driveway N of Site Entrance Driveway Foothill Rd./ Mission Canyon between W-E Impact from Related Projects Several area projects are proposed for the project vicinity; two are north of the project site and two are southwest of the site. Each of these four projects is only a single dwelling unit and will not add a significant amount of noise to the project area. There are two larger proposed projects. One is a twelve unit residential development approximately 0.8 miles southwest from the closest point of the Botanic Garden perimeter. The other is an expansion for the Natural History Museum approximately 0.8 miles to the south of the closest point of the Botanic Garden perimeter. None of the planned or pending area projects are within close proximity to the project site and would not combine to create a cumulatively significant impact. Other related projects, including those recently completed by the Botanic Garden and other minor additions or remodels, would not result in long-term noise generation since use levels and intensity would not change, and short-term construction related noise generation would not be significant given the scale of the projects and their location relative to one another. Rebuilding residences in and around the project site that were destroyed in the Jesusita Fire will result in temporary constructionrelated noise. However, this would be short-term and standard conditions limiting construction to daytime hours would help to alleviate this impact. Cumulative construction related and operational impacts would be less than significant and the project s contribution would not be cumulatively considerable. Impact of Ambient Noise on Project Surrounding land use primarily consists of low density residential development. There are no now noisegenerating land uses in the vicinity of the Garden that would expose Garden visitors, staff, and residences to ambient noise above background levels. Therefore, the cumulative noise environment would not significantly impact users of the Garden under the proposed project. The Mission Canyon area will likely experience a period of increased ambient noise associated with recovery and reconstruction after the Jesusita Fire. This will be short-term and it is expected that ambient noise will return to its normal level once the community has been rebuilt Mitigation Measures Construction Noise Impacts (N 1) Construction activities from project redevelopment may impact existing surrounding residential uses. Such impacts are primarily onsite and are mitigated by required compliance with grading/construction permits. Vital Mission Plan July 2009

13 N1-1 In order to mitigate construction activity noise the following mitigation measures are required. All construction and general maintenance activities, except in an emergency, shall be limited to the hours of 8:00 a.m. to 5:00 p.m., Monday through Friday. No construction shall occur on State holidays (e.g. Thanksgiving, Labor Day). Nonnoise generating construction activities such as interior painting are not subject to these restrictions. Staging areas shall be located away from existing residences. All construction equipment shall use properly operating mufflers. Stationary construction equipment that generates noise exceeding 65 dba at the property boundaries shall be shielded to P&D s satisfaction and shall be located as far as possible from occupied residences. Temporary noise barriers shall be erected along the line-of-sight to any residence within 1,600 feet of the noise source activity. Electrical power shall be used to run air compressors and similar power tools. Plan Requirements and Timing: Construction plans shall specify the above requirements. These plans shall be approved by P&D prior to issuance of the grading permit. Monitoring: P&D, or a designated monitor, shall conduct periodic site inspections during the construction period to ensure compliance and respond to complaints. Operational Noise Impacts (N 2) The following measure is recommended to avoid potential nocturnal noise nuisances resulting from nighttime events. N2-1 All music and organized social gathering events shall end in sufficient time to allow for attendees to disperse and exit the property by no later than 10 p.m. on weekdays and 11 p.m. on weekends. Amplified sound shall cease by 9 p.m. on weekdays and 10 p.m. on weekends. Sound amplification equipment shall be directed away from residences. Plan Requirements and Timing: Prior to Zoning Clearance issuance of permits for Land Use Permit approval under this project, the s shall submit to P&D for review and approval, a detailed scheduledocumentation from their website and rental contracts demonstrating compliance with this mitigation. Monitoring: P&D shall, or a designated monitor, shall conduct periodic site inspections throughout the life off the project operations to ensure compliancerespond to neighbor complaints. The applicant shall submit annual reports at the beginning of each calendar year to the County documenting compliance with this condition for the prior year. The reports shall include the dates and times that such events are held and what type of music is used, if any. The report shall also include a log of complaints received by neighbors and what measures are being taken to respond to the complaints. Vital Mission Plan July 2009

14 4.8.6 Residual Impacts 4.8 NOISE With implementation of the above mitigation measures designed to reduce construction noise, the proposed project s potentially significant impacts would be reduced to a less than significant level (Class II). Operational noise impacts are considered less than significant (Class III) however, mitigation is recommended. Cumulative impacts are considered less than significant and the proposed project s contribution to cumulative noise impacts is not cumulatively considerable (Class III). Vital Mission Plan July 2009