06 16 20 PWA_02_02 Exh2 - IS-MND

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INITIAL STUDY/MITIGATED NEGATIVE DECLARATION FAIRVIEw BRIDGE REPLACEMENT AND STREET IMPROVEMENTS w MAY 2020 (9TH STREET TO 16TH STREET) PROJECT `J" SANTA ANA. CALIFORNIA Operation. Potential long-term noise impacts under the Future Plus Project condition are solely from traffic noise. Future traffic noise levels at all 92 receptor locations were determined using either the worst -case traffic operations (prior to speed degradation) or the 2040 a.m. peak -hour traffic volumes obtained from the TIA,51 whichever were lower, as described above. Long-term traffic noise impacts were evaluated based on the noise standards in the City's General Plan Noise Element. According to the Noise Element, the long-term operational noise standard for residential uses is 65 dBA Community Noise Level Equivalent (CNEL). A 3 dBA change is the lowest level that is barely perceptible by the average human ear in an outdoor environment. Under CEQA, a comparison is made between the Existing No Project and Future Plus Project noise levels. A receptor is considered significantly impacted under CEQA if an increase of 3 dBA or more occurs and the Future Plus Project traffic noise level is 65 dBA CNEL or more. As shown in Table 6.1 in Appendix B of the NSR (Appendix A of this IS/MND), the Project -related traffic noise increase (from Existing No Project to Future Plus Project) at all 92 modeled receptor locations would be less than 3 dBA and would not be perceptible to the human ear in an outdoor environment. Although noise level results from FHWA TNM 2.5 are described using the Leq level and the City's noise standards are described using the CNEL level, the change in noise level from Existing No Project to Future Plus Project would be the same between the Leq and CNEL. Therefore, long-term noise impacts related to operations of the proposed Project would be less than significant, and no mitigation is required. The modeled future noise levels were also compared to the Caltrans Noise Abatement Criteria (NAC) to determine whether noise abatement should be considered under NEPA, because the Project would utilize federal transportation funding. The following noise barriers (NBs) were analyzed to shield receptor locations that would be exposed to traffic noise levels approaching or exceeding the Caltrans NAC for the future Project conditions: NB No. 1: A 169 ft long barrier along the right-of-way and private property line on the northbound side of Fairview Street between Civic Center Drive and 9th Street was analyzed to shield Receptor R-5. NB No. 2: A 129 ft long barrier along the right-of-way and private property line on the southbound side of Fairview Street between Civic Center Drive and 9th Street was analyzed to shield Receptor R-8. • NB No. 3: A 113 ft long barrier along the right-of-way and private property line on the southbound side of Fairview Street between West 9th Street and West 12th Street was analyzed to shield Receptor R-14. 51 LSA Associates, Inc. 2018b. op. cit. R:\WKE1702\ISMND\Final ISMND\Fairview Street Bridge Final ISMND.docx (05/26/20) 3-81