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4. ENVIRONMENTAL ANALYSIS 4.5 NOISE — Noise was measured by ESA staff at a sand and aggregate processing facility in Tracy.1 At a _ distance of 100 feet, daytime hourly noise levels reached 78-80 dBA L.,with a maximum noise level of about 98 dBA L.. The asphalt plant was not in operation during the time the measurements were taken, and noise from the burner used in the asphalt plant could generate higher noise levels. It is assumed that noise levels generated by the permanent and portable processing plants proposed as part of the Applicants' project would be about the same. Processing plant noise could result in increased noise levels at nearby residences. The residences located adjacent to the northeast side of the site(along the south side of Blewett Road) would be most affected by noise from the portable temporary processing plant, which would he located — approximately 1,600 feet away during the first two years of mining and also during the last phase of mining,Phase IX. At this distance,processing plant noise would attenuate to 54-56 dBA L,, and 74 dBA L.at the residential site. Located approximately 2,000 feet away, noise generated by the permanent processing plant would attenuate to 52-54 L.1 dBA and 72 Lu as dBA at the nearest residence. The noise levels generated from both plant locations exceed ambient nighttime noise levels at the residence by more than 3 dBA(on weekdays and weekend days)as well as the nighttime maximum standard of 65 dBA I.established by the San Joaquin Development Title. Moreover,the resultant noise levels also exceed weekend day daytime noise levels by more than 3 dBA(while not affecting weekday daytime levels). Therefore,without implementation of mitigation, processing plant noise would result in a significant impact. The residence located west of the southern end of the project site on Kloster Road(across the Delta-Mendota Canal) would not be affected by noise generated by the temporary portable processing plant, which is located approximately 4,400 feet away,or the permanent processing — plant, which would be located approximately 3,000 feet away. Located approximately 3,000 feet away,noise generated by the permanent processing plant would attenuate to 48-50 Lq dBA and 68.5 dBA L,,,,,,. While the resultant average noise level would be lower than existing average daytime and nighttime ambient noise levels at the residence,the maximum noise level exceeds the nighttime maximum standard of 65 dBA L,,,ar established by the San Joaquin Development Title by slightly more than 3 dBA. This would be a potentially significant impact. — Mitigation Measure 45.2: Implementation of Mitigation Measures 4.5.1 and 4.5.2 would _ reduce impacts of processing plant noise on local residents to a less-than-significant level. Significance after Mitigation: Less-than-Significant. 1 Measurements were collected in 1993 and presented in the noise section of the Granite Contraction Company — Vernalis Project EIR, 1993 prepared for Stanislaus County. These measurements are comparable to similar noise measurements of processing plants that are presented in other environmental reviews,including the DSS Engineering Contractors Proposed Koster Road Qwrry Excavation Application(QX-96-1)Final Environmental Impact Report(prepared by EDAW for San Joaquin County). RMC Pacific vernalis Quarry Miring and Reciamadon Roiea 4.5-16 ESA/203015 Admwistratr,e Draft EQt March 2004