2014-028 - Approving General Plan Amendement No. 2014-01

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City of Santa Ana -Park View at Town and Country Manor Draft EIR 4.5.4 - Thresholds of Significance Noise According to the CEQA Guidelines' Appendix G Environmental Checklist, to determine whether noise impacts are significant environmental effects, the following questions are analyzed and evaluated. Would the project result in: a.) Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? b.) Exposure of persons to or generation of excessive groundborne vibration or groundborne noise levels? c.) A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project? d.) A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? e.) For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? f.) For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? Thresholds for Substantial Noise Increase The CEQA Guidelines and the City of Santa Ana General Plan provide no definition of what constitutes a substantial noise increase; however, Caltrans provides guidance that can be used to define substantial changes in noise levels that may be caused by a project. The thresholds below generally apply to transportation noise that is usually expressed in terms of average noise exposure during a 24 -hour period, such as the Day/Night Average Level (Ldn) or CNEL. Project - generated increases in noise levels that exceed those outlined in the thresholds below and that affect existing noise sensitive land uses (receptors) are considered substantial and, therefore, would constitute a significant noise impact. The project will create a significant noise - related impact if it would: • Increase noise levels by 5 dB or more where the existing noise level is less than 65 dB. • Increase noise levels by 3 dB or more where the existing noise level is 65 to 70 dB. On the basis of the City of Santa Ana's normally compatible residential exterior noise threshold of 65 dBA, a noise level increase of 3 dB or more would be considered significant in areas where ambient conditions are greater than 65 dBA. Michael Brandman Associates 4.5 -9 H\Cl t(PN -Rn) 327b32]003MMVB2]0030 Sec01 Noi�.doc