Item 26 - Public Hearing Vista Heritage Charter School (601 North Fairview Street)

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Vista Charter Public Schools District Office and Outdoor Space Project CEQA Exemption 15183 The GPU EIR described that Mitigation Measure N-1 would reduce potential noise impacts during construction to the extent feasible. However, due to the potential for proximity of construction activities to sensitive uses, the number of construction projects potentially occurring simultaneously, and the potential duration of construction activities, construction noise could result in a temporary substantial increase in noise levels above ambient conditions. Therefore, impacts would remain significant and unavoidable. The GPU EIR determined that buildout of the General Plan Update would cause substantial traffic noise to increase on local roadways and could locate sensitive receptors in areas that exceed established noise standards. While Mitigation Measure N-2 would reduce potential interior noise impacts to future noise sensitive receptors below thresholds, there are no feasible or practical mitigation measures available to reduce project -generated traffic noise to less than significant levels for existing residences along affected roadways. Thus, the GPU EIR determined that traffic noise would remain a significant and unavoidable impact. The GPU EIR discussed that construction activity would generate varying degrees of ground vibration, depending on the construction procedures and equipment, that has the potential to exceed the Federal Transit Administration (FTA) criteria for architectural damage (e.g., 0.12 inches per second peak particle velocity (PPV) for fragile or historical resources, 0.2 inches/second PPV for non -engineered timber and masonry buildings, and 0.3 inches/second PPV for engineered concrete and masonry). The GPU EIR determined that implementation of Mitigation Measure N-2 and adherence to associated performance standards, would reduce impacts to less than significant levels. 4.13.2 Project Analysis The following section evaluates potential short- and long-term noise and ground -borne vibration impacts that would result from the proposed project. THRESHOLDS OF SIGNIFICANCE Exterior Noise Standards Chapter 18, Article VI, Noise Control, of the Municipal Code provides criteria for ambient noise measurements as well as noise standards for residential, school, hospital, and church use. When non -transportation (stationary) noise is the noise source of concern, the City applies performance standards from Municipal Code Section 18.312, Exterior Noise Standards, to ensure that noise producers do not adversely affect noise -sensitive land uses. Table 6, Exterior Noise Standards, summarizes the City's exterior noise standards. Table 6 Exterior Noise Standards Time Period Noise Levels dBA L50 L25 Ls L2 Lmax 7:00 a.m. -10:00 p.m. 55 60 65 70 75 10:00 p.m. - 7:00 a.m. 50 55 60 65 70 Note: A 5 dBA penalty shall be applied in the event of an alleged offensive noise such as impact noise, simple tones, speech, music, or an combination of thereof. If the measured ambient level exceeds any of the first four noise limit categories, the allowable noise exposure standard shall be increased to reflect the ambient noise level. If the ambient noise level exceeds the fifth noise limit category, the maximum allowable noise level under this category shall be increased to reflect the maximum ambient noise level. Source: City of Santa Ana, Santa Ana Municipal Code, Section 18.312, Exterior Noise Standards. Dec i y ouncil 26 — 103 1/16/20'2 e43