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 Mobile- Source Noise The transport of workers and equipment to the construction site and truck haul associated with demolition debris and soil haul would incrementally increase noise levels along roadways in the vicinity of the project site. Construction of projects could generate substantial truck trips for removal of debris and soil export or import for the construction of underground parking structures. It is not known at this point the amount of haul truck trips that would be required, when it would occur, or for how long. There would be a relatively high single -event noise exposure potential with passing trucks. Construction related traffic would likely use the major roads that provide regional access —such as Harbor Boulevard, Westminster Avenue, 5th Street, 1st Street, McFadden Avenue, and Gloxma Avenue which currently carry over 14,000 average daily traffic volumes. Typically, a doubling of vehicle trips would increase noise levels by 3 dB, which could be perceived adjacent to truck haul routes. Because of the relatively small size of the parcels, construction not would result in a doubling of traffic volumes. Though construction related truck traffic could cause substantial noise increases at sensitive uses along residential streets and collector roads, noise impacts from construction- related truck traffic would be limited to uses along haul routes along local and residential roads. Because construction related traffic is sporadic and short term, and because construction traffic is typically routed toward major roads, noise impacts related to construction traffic would be less than significant. Onsite Construction Equipment Noise The other type of short -term noise impact is related to demolition, grading, and building construction. Construction equipment can be considered to operate in two modes: stationary and mobile. Stationary equipment operates in one location for one or more days; mobile equipment moves around a construction site with variations in power settings and loads. To determine the energy average Ieq sound level from the equipments operation under varying power settings, the equipments noise rating at a reference distance, while operating at full power, is adjusted by considering the duty cycle of the activity. Table 5.9 -10 lists maximum construction equipment noise levels from 50 feet away and the industry standard duty cycles for typical development activities. October 2014 Page 5.9 -17