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i~ i~ Environmental Checklist i~ i~ i~ u i~ i~ i~ i~ i~ 7 ""'~ For CEQA Compliance L(25) is the noise level that is equal to or exceeded for 5 minutes in a 20 minute period. The L(°/o) is used for many city noise ordinance standards. A. Less Than Significant with Mitigation Incorporated. The City Noise Element uses outdoor and indoor noise limits for residential land uses impacted by transportation noise sources based on CNEL (Mestre Greve Associates 2007:4). The City Noise Element states that for residential land use, the exterior noise exposure level will not exceed 65 CNEL, and the interior noise exposure level will not exceed 45 CNEL (Mestre Greve Associates 2007:4). Additionally, the City Noise Ordinance is designed to control unnecessary, excessive, and annoying sounds from stationary (nontransportation) noise sources (Mestre Greve Associates 2007:4). Section 18-311 of the City's noise ordinance states that the entire city is designated as "Noise Zone 1." The noise ordinance criteria in Table 3-2 is used to determine impacts and appropriate mitigation. Table 3-2. City of Santa Ana Exterior Noise Ordinance Criteria Noise Level Not To Be Exceeded Maximum Time of Daytime 7 a.m. Nighttime 10 p.m. Exposure Noise Metric to 10 p.m. to 7 a.m. 30 Minutes/Hour L50 55 dBA 50 dBA 15 Minutes/Hour L25 60 dBA 55 dBA 5 Minutes/Hour L8.3 65 dBA 60 dBA 1 Minute/Hour L1.7 70 dBA 65 dBA Any Period of Time Lmax 75 dBA 70 dBA Two aspects of the project would be subject to the noise ordinance; (1) construction and (2) the proposed residential use adjacent to the commercial center to the south. Potential noise impacts are commonly divided into two categories; short-term and long term. Short-term impacts are usually associated with noise generated by onsite construction activities, which affect offsite surrounding land uses. Long-term impacts are further divided into noise generated by the proposed project, which impact offsite surrounding land uses (i.e.: car alarms or cars driving around the residential area), and noise generated by offsite land uses, which impact onsite land uses (i.e. traffic on South Fairview Street or Alton Avenue). Short-Term Noise Construction noise represents ashort-term impact on ambient noise levels. Noise generated by construction equipment, including trucks, • graders, bulldozers, concrete mixers, and portable generators, can reach high levels. The nearest homes to the proposed project site are located directly east. Heavy equipment could be operating as close as 20 feet to these residential areas for prolonged periods of time. The exact fleet and number of equipment pieces to be used on the construction site is not known; therefore, average noise levels for construction based on worst-case peak levels are the best estimates to use for assessing Alton Court Initial Study/Mitigated Negative Declaration 3-31 August 2007 J&S 00635.07 ~ 75A-97