Item 28 - Public Hearing - ZOA No. 20204-01 South Coast Technology Center

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South Coast Technology Center Project CEQA Exemption 15183 As shown in Table 4.13-5, vibration velocities from typical heavy construction equipment operation would range from 0.003 to 0.089 inch/second PPV at 25 feet from the source of activity. The nearest structure to the Project Site is the existing institutional use building located approximately 225 feet to the east of the Project Site. Table 4.13-5 shows that the vibration level during the operation of construction equipment would be approximately less than 0.0001 inch/second PPV to 0.0033 inch/second PPV at 225 feet. As a result, construction groundborne vibration would not exceed the 0.2 inch per second PPV significance threshold for human annoyance or 0.3 inch/second PPV significance threshold for building damage at the nearest structures. It should be noted that GPU PEIR MM N-2, which applies to projects utilizing pile driving during construction, and GPU PEIR MM N-3, which applies to residential projects located within 200 feet of existing railroad lines, are not applicable to the Project since the Project would not include pile driving and is not a residential project. In addition, the Noise and Vibration Assessment prepared for the Project (Attachment J) satisfies the requirements of GPU PEIR MM N-4, which requires industrial projects subject to CEQA to conduct a noise and vibration analysis. Therefore, vibration impacts would be less than significant impact during construction. Long -Term Operational Vibration Impacts The proposed industrial uses on the Project Site would not generate groundborne vibration that could be felt by the nearest sensitive receptors. However, heavy duty trucks associated with operation of the proposed Project would occasionally travel through the surrounding roadways. According to the FTA, it is unusual for vibration from sources, such as buses and trucks, to be perceptible, even in locations close to major roads.36 As such, it can be reasonably inferred that operation of the proposed Project would not create perceptible vibration impacts to the nearest sensitive receptors. Therefore, vibration impacts related to human annoyance and building damage during operation would be less than significant. Summary of Project -Generated Vibration Impacts Based on the above, the Project's construction and operational vibration impacts would be less than significant. The Project would not result in new or substantially more severe impacts compared to the determinations of the GPU PEIR, which concluded that the Project's construction and operational vibration impacts would be less than significant with mitigation incorporated. Therefore, no new project -specific mitigation measures are required. EXCESSIVE NOISE NEAR AIRPORTS The nearest airport to the Project Site is the John Wayne Airport located approximately 2.9 miles to the southeast. The Project Site is not located within two miles of the airport. Additionally, the Project Site is not located within the vicinity of a private airstrip or related facilities. Therefore, Project implementation would not expose people residing or working in the Project area to excessive noise levels associated with aircraft. As such, the impacts would be less than significant. Based on the above, impacts related to airport noise would be less than significant. The Project would not result in new or substantially more severe impacts compared to the determinations of the GPU PEIR, which concluded that the airport noise impacts would be less than significant. Therefore, no new project -specific mitigation measures are required. 36 Federal Transit Administration, Noise and Vibration Impact Assessment Manual, Section 5.2, Sources of Transit Ground -borne Vibration and Noise, September 2018. July 2024 Page 84