2014-069 - Final Environmental Impact Report No. 2014-01

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HARBOR BLVD. MIXED USE TRANSIT CORRIDOR PLAN FINAL FIR CITY OF SANTA ANA 5. Environmental Analysis NOISE The operation of proposed commercial, office, and retail uses next to residential uses would have the potential to introduce new stationary sources of noise, such as HVAC units, and noise from entertainment establishments such as live music, patrons voices, and speakerphones. These sources could have the potential to cause sporadic exceedances of the noise standards in the municipal code or to generate noise levels that would be readily perceptible (greater than 5 dBA over the ambient noise) at residential properties immediately adjacent to future commercial, office, and retail uses. It should be noted that the existing uses in the project area are predominantly commercial and RV /auto - related uses. The Harbor Corridor Plan would not necessarily introduce new sources of stationary noise, but would increase the residential density in the area, which would have the potential to expose persons to stationary noise above the City's noise ordinance criteria (see Table 5.9 -4). No site - specific development is proposed at this time. Therefore, the specifications, design features, and /or location of these potential noise sources and the resulting effect of future development on nearby sensitive receptors cannot be quantified at this time. Noise from the operation of commercial, office, and retail uses on nearby sensitive receptors would be potentially significant. Impact 5.9 -4: Construction activities would generate high levels of ground -bome vibration. [Threshold Impact Analysis: There would be no long -term operational sources of vibration with the project, but project construction may expose people to ground borne vibration and noise. Buildout of the Harbor Corridor Plan would occur over a period of several years and would consist of several projects with their own construction time frames and equipment. It should be noted that although the total length of construction activities for the buildout of the entire Harbor Corridor Plan is estimated at approximately 20 years, individual construction activities for each project would have their own schedule and would only affect areas near the construction site The closest vibration - sensitive structures are the existing and future residential uses in the project area. In addition, residential areas immediately adjacent to the boundaries of the project area are also considered vibration sensitive and would have the potential to be affected by construction activities during implementation of the Harbor Corridor Plan. No properties within the project site were identified as potential historic resources, which have lower thresholds for vibration. Construction activities can generate varying degrees of ground vibration, depending on the construction procedures, construction equipment used, and proximity to vibration - sensitive uses. Operation of construction equipment generates vibrations that spread though the ground and diminish in amplitude with distance from the source. Vibration is typically noticed nearby when objects in a building generate noise from rattling windows or picture frames. It is typically not perceptible outdoors, and therefore impacts are based on the distance from the vibration source to the nearest building. The effect on buildings further varies depending on soil type, ground strata, and building construction. The generation of vibration can range from no perceptible vibrations at the lowest levels to slight damage at the highest levels. Ground vibrations from construction activities rarely reach levels that can damage structures, but can reach the audible and perceptible ranges in buildings closest to a construction site. Page 5.9 -14 PlaceWorkr