Laserfiche WebLink
<br />18 <br /> <br />Mitigation Measure 3: None required. <br /> <br />Impact 4: Mechanical Equipment Noise. The new and replacement sports lighting in the <br />proposed project would not permanently increase noise levels at noise-sensitive uses <br />in the vicinity. This is a less-than-significant impact. <br /> <br />With the proposed project, the existing sports lighting fixtures around the perimeter of the <br />Bechet/Griffin Field would be replaced with 12 new 70-foot light standards, and the existing lights <br />at the tennis court would be replaced with six new 50-foot light standards. Additionally, seven new <br />60- to 70-foot light standards would be installed around the perimeter of Mitchell Field. Each ligh t <br />standard would consist of 1,500-watt metal halide lamp fixtures with an aluminum reflector, a light <br />hood, and a visor to direct light onto the field. These proposed high power lamps reduce the number <br />of required fixtures and increase light beam control and efficiency. The light standards would be <br />expected to increase noise levels at adjacent noise-sensitive land uses by less than 1 dBA. <br />Therefore, noise levels would not permanently increase due to mechanical equipment noise. This <br />would be a less-than-significant impact. <br /> <br />Mitigation Measure 4: None required. <br /> <br />Impact 5: Temporary Construction Noise. Existing noise-sensitive land uses would not be <br />exposed to construction noise levels in excess of the significance thresholds for a <br />period of more than one year. This is a less-than-significant impact. <br /> <br />Noise impacts resulting from construction depend upon the noise generated by various pieces of <br />construction equipment, the timing and duration of noise-generating activities, and the distance <br />between construction noise sources and noise-sensitive areas. Construction noise impacts primarily <br />result when construction activities occur during noise-sensitive times of the day (e.g., early <br />morning, evening, or nighttime hours), the construction occurs in areas immediately adjoining <br />noise-sensitive land uses, or when construction lasts over extended periods of time. Where noise <br />from construction activities exceeds 60 dBA Leq and exceeds the ambient noise environment by at <br />least 5 dBA Leq at noise-sensitive uses in the project vicinity for a period exceeding one year, the <br />impact would be considered significant. <br /> <br />Construction activities generate considerable amounts of noise, especially during earth-moving <br />activities when heavy equipment is used. Table 6 presents the typical range of hourly average noise <br />levels generated by different phases of construction measured at a distance of 50 feet. Hourly <br />average noise levels generated by excavation equipment associated with the project are calculated to <br />range from 71 to 89 dBA Leq measured at a distance of 50 feet. Construction-generated noise levels <br />drop off at a rate of about 6 dBA per doubling of the distance between the source and receptor. <br />Shielding by buildings or terrain often result in lower construction noise levels at distant receptors. <br /> <br />Construction for the proposed project would include minor excavation to construct the foundations <br />for the light standards. Noise generated by construction activities would temporarily elevate noise <br />levels at adjacent noise-sensitive receptors, but this would be considered a less-than-significant <br />8.A. - Page 134