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San Joaquin County Community Environmental Setting,Impacts,and Mitigation Measures _ Development Department - Noise Table 3.J-1. Summary of Long-Term Noise Level Measurements near Proposed DeSilva Gates Quarry Average Measured Hourly Noise Levels,dBA _ Loudest-Hour Time of Quietest-Hour Time of Position Day' Ley(]h) Occurrence Ley(I h) Occurrence Daily La„ LT-1 Weekday 48.6 8:00 a.m. 41.0 2:00 a.m. 50.4 — Weekend 54.5 9:00 a.m. 38.8 2:00 a.m. 53.9 Average 52.3 Minimum daytime 1 hour Ley:' 38 dBA Minimum nighttime 1 hour Ley:b 36 dBA — LT-2 Weekday 54.5 8:00 a.m. 46.4 11:00 P.M. 56.3 Weekend 50.3 8:00 a.m. 45.5 2:00 a.m. 54.0 Average 55.7 — Minimum daytime 1 hour Ley:b 46 dBA Minimum nighttime 1 hour L�y:b 45 dBA LT-3 Weekday` 65.8 6:00 a.m. 55.2 1:00 a.m. 68.8 Minimum daytime 1 hour Ley:b 57 dBA Minimum nighttime 1 hour Ly:' 54 dBA Weekday indicates average of four 24-hour days: Tuesday October 4'"through October Friday 7'". Weekend indicates average of two 24-hour days: Saturday October 8"and Sunday October 9'. Average indicates average of all six 24-hour days. b During entire measurement period ` Values developed from data collected Tuesday October 4"though Thursday October 7.No weekend data was collected at this position. Short-Term Noise Monitoring Short-term monitoring was conducted on Monday October 3, 2005,using — Larson-Davis Model 812 Precision Type I sound level meters (serial numbers 0432 and 0430). During the short-tetra measurements,Jones& Stokes staff attended each meter. The meters were paused if a significant non-traffic source — of noise occurred,such as an aircraft flyover. The meter was restarted and the Ley collection continued after the non-traffic sound subsided. The Ley value measured during the measurement period was logged manually. The calibration — of the meter was checked before and after the measurement using a Larson-Davis Model CA250 calibrator(serial number 3143). Temperature, wind speed,and humidity were recorded manually during the short-tern monitoring session using a Kestrel 3000 portable weather station. During the short-term measurements,skies were clear. Wind speeds were — typically in the range of 0 to 16 kph(0 to 10 mph). Temperatures were in the range of 18 to 23'C (64 to 737),with relative humidity in the range of 31 to 44%. Traffic on I-5 and SR 132 was the dominant noise source observed during all short-term measurements. Wind in the trees and occasional aircraft overflights were also audible during the measurements. The information gathered during the — short-term measurements is summarized in Table 3.J-2. DeSilva Gates Quarry Project Draft Environmental Impact Report 3_,1.4 J8s 05105.05