ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

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equipped with noise control devices, construction-generated source noise could result in the exposure of persons to or generation of noise levels in excess of applicable standards, annoyance and/or sleep disruption to occupants of any existing noise-sensitive land uses in the project vicinity, and/or create a substantial temporary increase in ambient noise levels. As a result,this impact would be potentially significant. IMPACT Noise—Long-Term Increases in Traffic Source Noise Levels. Because operation would generate few 4.4-2 traffic trips in comparison to existing traffic volumes on local roadways, the proposed project would not result in a noticeable change in the traffic noise contours of area roadways. Thus, long-term increases in traffic source noise levels would not result in the exposure of persons to or generation of noise levels in excess of applicable standards or create a substantial permanent increase in ambient noise levels at existing noise- sensitive receptors.As a result, this impact would be less than significant. As described in Section 4.11, "Transportation and Circulation,"the proposed project would generate 20 one-way employee passenger vehicle trips per day and less than one truck haul trip per day. These trips are less than 1.0% of existing traffic volumes on local area roadways. Typically,traffic volumes have to double before the associated increase in noise levels is noticeable(3 dBA [CNEL/La]) along roadways. Therefore,the addition of these daily trips on the local roadway system to existing volumes would be negligible. The operation of the project would not result in a noticeable change in the traffic noise contours of area roadways and long-term increases in traffic source noise levels would not result in the exposure of persons to or generation of noise levels in excess of applicable standards or create a substantial permanent increase in ambient noise levels at existing noise-sensitive receptors. As a result,this impact is considered less than significant. IMPACT Noise—Long-Term Increases in Stationary-and Area-Source Noise Levels.Long-term on-site 4.4-3 stationary-source noise would not result in the exposure of persons to or generation of noise levels in excess of applicable standards or create a substantial permanent increase in ambient noise levels in the project vicinity.Area sources of noise(e.g., landscape maintenance equipment) would not be anticipated to differ substantially from existing noise equipment levels.As a result, this impact would be less than significant. For the WQCF, long-term operation would increase the use of on-site noise-generating stationary equipment such as electrical pump motors, air compressors, fans, aerators, chlorination systems,transformers, and emergency generators. Without proper noise control or enclosure, such equipment could result in noise levels of more than 100 dBA at 3 feet from the source depending on the exact type and size (EPA 1971). Specifically,pumps could result in noise levels of more than 90 dBA at 3 feet,transformers 80 dBA at 3 feet, and electrical motors 100 dBA at 3 feet(EPA 1971). Based on this equipment noise level and a typical noise-attenuation rate of 7.5 dBA/DD for soft sites,the operation of on-site stationary equipment would result in a modeled exterior noise level at the closest noise-sensitive receptors, located approximately 650 feet from the project site,of approximately 42 dBA. In addition,the operation of on-site stationary equipment would result in a modeled noise level of approximately 69 dBA at 50 feet. This noise level would be in compliance with the City of Manteca's noise ordinance,which limits noise in industrial area to 70 dBA at 50 feet. Such equipment would also likely be housed in buildings, enclosed, and/or equipped with interior sound insulation resulting in substantially lower noise levels. Area sources of noise(e.g.,landscape maintenance equipment)would not be anticipated to differ substantially from existing noise equipment levels. For the wastewater collection system, long-term operation would increase the use of noise-generating stationary equipment such as electrical pump motors and generators associated with the proposed permanent and interim wastewater pumping stations. The location of these is not known at this time;however,the pump motors would be installed below grade and generators would only operate during emergencies and testing on a frequency of once per week to once per month(e.g.,temporary in nature). The City of Manteca's noise ordinance would govern the design of pump stations within the city, including emergency generators, and the San Joaquin County noise ordinance exempts activities associated with the maintenance of public utilities. Thus,long-term on-site Manteca WQCF and Collection System Master Plans EIR EDAW City of Manteca 4.4-19 Noise