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1 <br /> ' Draft Supplemental Environmental Impact Report Page IV.0-1 <br /> Forward Inc. Landfill 2018 Expansion Project <br /> ' C. NOISE <br /> This section describes the existing and likely future noise environments in the vicinity of the proposed <br /> Forward Landfill Expansion project to take into account the proposed changes to the project described <br /> in this Supplemental EIR. It also addresses the project's conformity with the San Joaquin County <br /> General Plan and Noise Ordinance. The impacts and mitigations in this section replace those in Section <br /> ' IV.0 of the 2013 EIR. <br /> Setting <br /> Background <br /> ' To describe noise environments and to assess impacts on noise-sensitive areas, a frequency weighting <br /> measure,which simulates human perception, is commonly used. It has been found that A-weighting <br /> of sound levels best reflects the human ear's reduced sensitivity to low frequencies, and correlates well <br /> with human perceptions of the annoying aspects of noise. The A-weighted decibel scale (dBA)'is cited <br /> in most noise criteria. Decibels are logarithmic units that conveniently compare the wide range of <br /> sound intensities to which the human ear is sensitive. Table IV.0-1 identifies typical ranges of decibel <br /> ' levels for common sounds heard in the environment. <br /> Table IV.0-1: Typical Noise Levels <br /> Noise Level dBA Outdoor Activity Indoor Activity <br /> 90+ Gas lawn mower at 3 feet,jet flyover Rock band <br /> ' at 1,000 feet <br /> 80-90 Diesel truck at 50 feet Loud television at 3 feet <br /> ' 70-80 Gas lawn mower at 100 feet, noisy Garbage disposal at 3 feet,vacuum <br /> urban area cleaner at 10 feet <br /> ' 60-70 Commercial area Normal speech at 3 feet <br /> 40-60 Quiet urban daytime, traffic at 300 Large business office,dishwasher <br /> feet next room <br /> 20-40 Quiet rural,suburban nighttime Concert hall(background),library, <br /> bedroom at night <br /> 10-20 Broadcast / recording studio <br /> 0 Lowest threshold of human hearing Lowest threshold of human hearing <br /> Source:(modified from Caltrans Technical Noise Supplement,1998) <br /> 1 A decibel (dB) is a unit of sound energy intensity. Sound waves, traveling outward from a source, exert a sound pressure level <br /> (commonly called"sound level")measured in dB. An A—weighted decibel(dBA)is a decibel corrected for the variation in frequency <br /> response to the typical human ear at commonly encountered noise levels. <br />