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`. San Joaquin County Community Environmental Setting, Impacts,and Mitigation Measures Development Department Noise Impacts and Mitigation Measures Impact N-1 : Exposure of Noise-Sensitive Land Uses to Noise during Construction and Reclamation Activities in Excess of County Noise Ordinance Standards (Less than Significant with Mitigation Incorporated) Equipment noise associated with overburden removal and construction of the mining facility,earthen berms,and aggregate processing facilities could intermittently generate high noise levels on and adjacent to construction sites. Equipment noise during reclamation activities would be similar to construction activities and could also generate high sound levels on and adjacent to reclamation sites. Reclamation activities are temporary and therefore are treated as construction activities in the analysis. Noise from reclamation activities would typically be less than construction activities because most of the reclamation activity would be below the elevation of existing ground. The earth surrounding the pit provides a natural shield for noise propagating to noise-sensitive locations. tr Therefore,as the floor of the reclaim pit rises in elevation,equipment noise in the reclaim pits will increase. y Table 3.J-5 summarizes typical noise levels produced by construction equipment. The three loudest pieces of equipment likely to be operated at any given location during construction operations include a scraper,bulldozer, and a truck. The combined noise level of these three pieces of equipment is 88 dBA Leq. Table 3.J-5 also summarizes projected construction noise levels at various distances from a construction site. Title 8 California Code of Regulations Section 1592"Warning Methods" requires that every vehicle with a haulage capacity of 2.5 cubic yards or more used to haul dirt,rock, concrete,or other construction material be equipped with L a warning device that operates automatically while the vehicle is backing. The warning sound must normally be audible from a distance of 200 feet and must sound immediately on backing. The sound level produced by backing alarms is +� typically as high as 107 dBA at 4 feet. (Society of Automotive Engineers 2003). This corresponds to 85 dBA at 50 feet. Because backing and alarms are intermittent,a nominal usage factor of 20%is reasonable. The corresponding r sound level is therefore 78 dBA-L�q at 50 feet. Although this sound level would not increase the assumed construction equipment sound level of 88 dBA L�q, backup alarms,by their very nature,tend to be distinctly audible and a source of _ annoyance. The results in Table 3.J-5 indicate that the 50 dBA Leq daytime standard could be exceeded within about 1,500 feet of construction activity,and the nighttime standard of 45 dBA L�q could be exceeded within about 2,300 feet of construction activity. r ` DeSilva Gates Quarry Project Draft Environmental Impact Report 3,J-9 As 05105.05