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Munn&Perkins Quarry Excavation Permit • A substantial temporary or periodic increase in ambient noise levels in the project vicinity above existing levels existing without the project. • Exposure of people residing or working in the project area to excessive noise levels,for a project located within an airport land use plan or,where such a plan has not been adopted,within two miles of a public airport or public use airport. • Expose people residing or working in the project area to excessive noise levels if the project is located in the vicinity of a private airstrip. The proposed project does not include any new sources of ground vibration.Additionally,the project site is not located within an airport land use plan,is not located within two miles of a public airport or within the vicinity of a private airstrip.Consequently,no impacts associated with these elements would be expected to occur,and these issues are not discussed further in this section. Applicable Project Significance Criteria Project-related noise exposure would affect nearby residential receivers between the hours of 9 p.m. and 5 a.m.Project-related noise from the Munn&Perkins asphalt plant and associated water truck, loader,and haul truck movements(on-and off-site)would be expected.The following impact criteria are applied to noise from these sources at the closest residential receivers to the project site. Significant project-related noise exposure would occur if the project stationary noise sources(e.g., asphalt plant)exceed the County's nighttime limit of 45 dB hourly Ley or the nighttime maximum 65 dB Lr„ax at off-site outdoor activity areas. Also, a significant impact would occur if noise from proposed project haul truck operations would exceed the applicable County noise exposure limits :Of 65 dB Ldn(exterior)or 45 dB Ldn(interior). Likewise, a significant impact would occur if noise exposure from project haul truck operations would produce noise exposure increases beyond the established FICON limits described above.Finally,a significant increase in nighttime awakenings of nearby residents due to project haul trucks on East River Road would be a significant noise impact. In this case,an increase in the probability of awakenings of 5 percent or more relative to the ambient condition (without the project) would be considered significant. The probability of nighttime awakenings was completed using the ANSI/ASA 512.6-2008 Part 6 recommendations/guidelines. Analyses Project-Related Noise Exposure from On-Site Sources A detailed assessment of recorded noise exposure and operating hours of the project asphalt plant completed by Bollard Acoustical Consultants,Inc. (August 18,2010)yielded noise exposure from the asphalt plant(and on-site ancillary sources) of approximately 40 dB Ley/Lmax at the closest residence to the east(Site A). Assuming standard spherical spreading loss(-6 dB per doubling of distance), and assuming that plant noise exposure is the same to the north as it is to the east, plant noise exposure at the closest residence to the north(near Site 3)would be approximately 43 dB Ley/Lm,,,.Alone,project-related noise exposure from on-site noise sources is not expected to exceed the applicable nighttime average of 45 dB hourly Ley or nighttime maximum of 65 dB LmsX noise exposure limits at off-site outdoor activity areas established by the County. Munn&Perkins Quarry Excavation Permit 3.4-12 ESA!211066 Draft EIR April 2011