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San Joaquin County Community Environmental Setting, Impacts,and Mitigation Measures Development Department Noise acoustic calibrator and complies with applicable requirements of the American National Standards Institute(ANSI)for Type 2 sound level meters. The existing noise environment in the vicinity of the project site was characterized by conducting continuous noise monitoring at three locations for seven days, starting at 12:00 p.m.Monday, October 3,2005,and ending at 12:00 p.m. Monday,October 10,2005. These locations are shown on Figure 3.J-1. Long-Term Site LT-1: near Koster Ranch—This noise monitor was located at the eastern fence line of the Koster Ranch near the Delta-Mendota Canal and was used to represent the residence on the ranch property. Primary noise sources affecting the site include distant traffic from 1-5, traffic crossing the canal bridge, and aircraft overflights. Long-Term Site LT-2: Near Koster Road across from Residence—The Site 2 .. monitor was located near the intersection of the orchard road with Koster Road, across from the residence on the eastern side of the intersection, which the monitor is intended to represent. Primary noise sources affecting the site include traffic on SR 132,and local traffic on Koster Road and the orchard road. Long-Term Site LT-3: North of SR-132—The Site 3 monitor was located near i residences located north of SR-132. Primary noise sources affecting the site include traffic on SR 132. The LD Model 700 sound level meters at Sites LT-1 and LT-2 ran continuously over the seven-day period. At Site LT-3,the meter ran for 4 days. Statistical descriptors are calculated for each 1-hour interval of the overall sample period. Statistical descriptors include the Lam,Lte, L33, and L90. The Lq represents the energy-average noise level for each interval period(see Introduction). The Lle, L33, and L90 describe the noise levels exceeded 10%, 33%and 90%of the time, respectively, during each sample interval. The Lgo is often used to describe the background(or ambient) sound level for a given area, or the sound level that characterizes periods during which typical noise sources in the area(such as traffic and aircraft overflights)are not contributing significantly to the sound level. Table 3.J-1 summarizes the results of the long-term ambient noise level monitoring. On average,the loudest sound levels at the long-term sites occurred between the hours of 6:00 a.m. and 10:00 a.m. The quietest sound levels occurred during the hours of 11:00 p.m. and 3:00 a.m. DeSilva Gates Quarry Project Draft Environmental Impact Report 3.J-3 J85 05105.05