Draft Environmental Impact Report - East Bay Municipal Utility District

Estates Reservoir Replacement Draft Environmental Impact ReportNoise and VibrationData were collected and analyzed in 1-hour intervals over the duration of the noisesurvey. The data for Estates Reservoir are shown on Figures 3.9-2a, 3.9-2b, 3.9-3aand 3.9-3b. During each hour noise levels are analyzed utilizing the statisticaldescriptors set forth in the Oakland Noise Ordinance. In addition, the hourly L eqand the maximum and minimum noise levels are presented for each hour. The chartalso shows the calculated day/night average noise level (L dn ) measured for each 24-hour period which ranged from 46 dBA L dn to 53 dBA L dn . The average for thefour-day period was 49-50 dBA L dn . Noise sources affecting the environment thatwere noted during an attended short-term measurement on the afternoon ofMonday, November 5, 2007 included cars that generated maximum noise levels of47-49 dBA, an aircraft overflight that generated a maximum noise level of 59 dBAand audible construction noise from residential construction occurring across thereservoir from the measurement location. The reservoir fountains were notoperating during the noise survey.Montclair Pumping Plant – The Montclair Pumping Plant is located near thesouthwest corner of the Estates Reservoir. Noise measurements of pumping plantequipment were made on February 6, 2008. Weather conditions werecool/overcast, with zero to very light winds. The pumps are located inside thepump station building. PG&E transformers are located outside. Sound levels weremeasured near the property corner, about 10 feet from the western façade of thepump station building. The measured ambient noise level, including the soundfrom the PG&E substation, was 55 dBA prior to operating the pumps. At the pumpstartup, sound levels incrementally increased momentarily by about 2 dBA to57 dBA, and then quickly dropped down to 55 to 56 dBA at the monitoringlocation. At the property line of the nearest residence, located about 35 feet fromthe pump station building, the sound level was 50 dBA. The operating pumps werebarely detectable and made no measurable contribution to the overall sound level inthe area. Noise levels were also monitored inside the pump station building. Theinterior noise level briefly reached 98 dBA L max during startup but typically rangedfrom 84 to 87 dBA during operation. The building effectively controls pump noise.sb09_001.doc 3-9.8 7/22/2009