Item 41 - Amendment Application No. 2022-01 and Appeal Nos. 2022-01 and 2022-02

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Community Plan Exemption Checklist City of Santa Ana Gary Avenue Business Park Project b) Generation of excessive ground borne vibration or ground borne noise levels? Construction No New Impact. Construction activities for the proposed Project would include demolition, excavation, and grading activities, which have the potential to generate low levels of groundborne vibration. People working in close proximity to the Project site could be exposed to the generation of excessive groundborne vibration or groundborne noise levels related to construction activities. The results from vibration can range from no perceptible effects at the lowest vibration levels, to low rumbling sounds and perceptible vibrations at moderate levels, to slight structural damage at the highest levels. Site ground vibrations from construction activities very rarely reach the levels that can damage structures, but they can be perceived in the audible range and be felt in buildings very close to a construction site. Demolition, excavation, and grading activities are required for the Project and can result in varying degrees of ground vibration, depending on the equipment and methods used, distance to the affected structures and soil type. Potential impacts of the Project are compared to the Federal Transit Administration (FTA) published standard vibration velocities for construction equipment operations in their 2018 Transit Noise and Vibration Impact Assessment Manual. Based on FTA data, vibration velocities from typical heavy construction equipment operations that would be used during Project construction range from 0.003 to 0.089 in/sec PPV at 25 feet from the source of activity, which is below the FTA's 0.20 PPV threshold for annoyance, as shown on Table N-5. The closest structure is the commercial use located approximately 40 feet from the Project construction area. Also, as shown Table N-5, construction VdB levels would not exceed 81 VdB at 40 feet (i.e., below the 100 VdB structural damage threshold). Therefore, no new impacts related to construction would occur from implementation of the Project. Table N-5: Construction Equipment Vibration Levels Equipment PPV at 25 Feet (in/sec) PPV at 40 Feet (in/sec) VdB at 25 Feet VdB at 40 Feet Large Bulldozer 0.089 0.0440 87 81 Caisson Drilling 0.089 0.0440 87 81 Loaded Trucks 0.076 0.0376 86 80 Jackhammer 0.035 0.0173 79 73 Small Bulldozer Tractors 1 0.003 0.0015 58 52 Source: Acoustical Assessment (Appendix K) Operation Once operational, the Project would not be a significant source of groundborne vibration. Groundborne vibration surrounding the Project currently result from heavy-duty vehicular travel (e.g., refuse trucks, heavy duty trucks, delivery trucks, and transit buses) on the nearby local roadways. Operations of the proposed Project would include passenger cars and trucks. Due to the rapid drop-off rate of ground -borne vibration and the short duration of the associated events, vehicular traffic -induced ground -borne vibration is rarely perceptible beyond the roadway right-of-way, and rarely results in vibration levels that cause damage to buildings in the vicinity. Therefore, the Project would result in no new impacts related to ground born vibration. c) For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? No New Impact. The Project would not expose people residing or working in the Project site to excessive noise levels from aircraft. The nearest airport is John Wayne Airport that is located approximately 1.5 miles 80