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 shown in this table, the operation of pile driving equipment and vibratory rollers would cause vibration levels that would exceed the thresholds for annoyance to residential uses. Since vibration levels dissipate rapidly with distance, pile driving at 350 feet or a vibratory roller at 100 feet from a sensitive receptor would not exceed the 78 VdB threshold for vibration annoyance. For equipment that produced lower vibrational energy, the vibration annoyance threshold distance would be considerably closer to the sources (e.g., for a large bulldozer, the annoyance threshold distance would be less than 50 feet between the source and the receiver). Construction that involves typical heavy construction equipment vibratory rollers, bulldozers, loaders, excavators, and jack hammers would result in vibration impacts when operated less than 100 feet from a given receptor. Several residences would be within 100 feet of parcels that may be redeveloped or within 100 feet of the street right- of-way and would be temporarily affected by the use of heavy construction equipment during the daytime. A review of aerial photographs shows that several residential buildings are at least 50 feet from the project boundaries. Because equipment would move around each construction site and vibration levels dissipate rapidly, vibration impacts at a given receptor would be sporadic and short -term; therefore, these impacts would be less than significant. However, the operation of pile driving equipment, which is a stationary equipment item, could potentially cause vibration levels that would be above thresholds at receptors up to 350 feet away. This would be a significant impact. Impact 5.9 -5: Construction activities would result in temporary noise increases in the vicinity of the proposed project. [Threshold NA] ImpactAnalysis: A project would normally have a significant effect on the environment if it would result in a substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project. Buildout of the Harbor Corridor Plan would occur over a period of several years and would consist of several smaller projects with their own construction time frame and equipment. Although the length of construction activities for buildout of the entire Harbor Corridor Plan is estimated at approximately 20 years, individual construction activities in each project would have their own schedule, and each project would only affect the area near it. Therefore, exposure of any one sensitive receptor to elevated construction noise levels would be from a few to several months in duration. Two types of short -term noise impacts could occur during construction: (1) mobile- source noise from transport of workers, material deliveries, and debris and soil haul and (2) stationary source noise from use of construction equipment. The closest noise - sensitive structures are the existing and future residential uses in the project area, churches, and the Santa Anita Park. 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. Several residences would be temporarily affected by the use of heavy construction equipment during the daytime. Commercial and retail uses within the project area are not considered noise - sensitive uses. Page 5.9 -16 PlaceWorkr