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Table 4.4-9 <br /> Typical Construction Equipment Noise <br /> Equipment Maximum Noise Level(dBA Lmax)50 Feet from Source <br /> Backhoe 80 <br /> Grader 85 <br /> Loader 85 <br /> Pile Driver 96-101 <br /> Jackhammer 88 <br /> Bulldozer 85 <br /> Truck 88 <br /> Scraper 89 <br /> Notes:dBA=A-weighted decibels;Lmax=maximum noise level <br /> Source: FTA 2006 <br /> Noise from two or more pieces of equipment would be greater than noise from one piece of equipment. Average <br /> noise levels would be less than maximum noise levels because equipment would not operate at 6x11 power all of <br /> the time,nor would the equipment remain in one location. With these considerations, an average noise level of 75 <br /> dBA Leq at a distance of 50 feet would be a reasonable value, assuming pile drivers would not be required during <br /> construction. Construction equipment may be considered a point source,with noise attenuation(reduction)of <br /> 6 dBA/DD from the source over hard surfaces such as concrete or water. Thus, a noise level of 80 dBA at 50 feet <br /> would be 74 dBA at 100 feet, 68 dBA at 200 feet, etc.Where the terrain between the source and receptor is <br /> vegetated and the line of sight from source to receptor is within 10 feet of the ground, called acoustically"soft" <br /> conditions,the noise attenuation may increase up to 7.5 dBA/DD. Based on these noise levels and a typical noise- <br /> attenuation rate of 7.5 dBA/DD, construction activities would result in a modeled exterior noise level at the <br /> closest noise-sensitive receptors, located approximately 650 feet from the project site,of approximately 50 dBA, <br /> with intermittent maximum noise levels of approximately 60 dBA Lmax• <br /> Similar to the WQCF expansion,construction equipment would be the principal source of noise during <br /> installation of the wastewater collection system(e.g.,pipelines and pump stations). Typical equipment for the <br /> collection system installation would include backhoes,trucks, loaders,pavement breaking tools, and generators to <br /> support compressors and welders. The diesel engines of the equipment would be the loudest noise source except <br /> when jackhammers or other sorts of pavement breakers would be used, for which times the noise from impact <br /> tools would be dominant. <br /> Pipeline installation would be linear in nature,moving at a rate of 100-200 feet per day. There would be a series <br /> of activities at each location: trenching and excavation,with pavement breaking if needed;pipeline installation; <br /> backfill; and paving. Paving would occur after installation of the pipeline and the backfill activities. The noise at <br /> adjacent residences or sensitive land uses would occur intermittently for one to three days at any individual <br /> residence. It is not anticipated that any element of the project would be located less than 50 feet from sensitive <br /> receptors, and noise levels would not exceed 75 dBA Leq averaged over any hour,with intermittent maximum <br /> noise levels at 85 dBA. <br /> Noise from construction activities that occur between 7 a.m. and 7 p.m., and 6 a.m. and 9 p.m. is exempt from the <br /> provisions of the City of Manteca and San Joaquin County noise ordinances,respectively. Although construction <br /> of the proposed project would be anticipated to occur primarily during the daytime hours,the exact hours of <br /> construction are not specified in the project description. Thus, if construction activities were to occur during the <br /> more noise-sensitive hours (e.g., evening,nighttime, and early morning) or construction equipment not properly <br /> EDAW Manteca WQCF and Collection System Master Plans EIR <br /> Noise 4.4-18 City of Manteca <br />