SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequencesresidential areas to exceed generally accepted land use compatibility criteria. Based on modelingresults for SBMR, there would be a modest expansion of Zone II conditions and some small changesin the location of Zone III conditions within the SBMR ROI. Zone II conditions would expandeastward by about 985 to 1,300 feet to encompass additional troop and family housing areas on theeastern side of the Main Post.Zone II conditions would affect some undeveloped areas north and south of SBMR, but would notexpand into existing off-post residential areas. Solomon Elementary School and Hale KulaElementary School would remain under the Zone II noise contour. In the absence of the nighttimenoise sensitivity factor, Hale Kula Elementary is within Zone I conditions versus Zone II.Zone III conditions would remain unchanged or actually contract slightly in the northern portion ofthe Main Post, but would expand eastward by about 325 to 490 feet in the southwest corner of thecantonment area. Some additional family housing units would be encompassed by the Zone IIIcontour in this area. The Zone II and Zone III noise contours would affect a larger portion of thedeveloped cantonment area than occurs under existing conditions.Noise from increased ordnance use would not significantly increase noise levels experienced onpeople residing on or working at SBMR. The primary factor resulting in the slight expansion of ZoneII and Zone III noise exposure areas would be an increase in the number of 155mm artillery roundsfired and an increase in nighttime artillery and mortar firing.As with the existing condition, only about 10 percent of the total artillery and mortar firing wouldoccur during nighttime hours (10:00 PM to 7:00 AM), although the number of individual ordnanceitems fired or detonated at night would increase by about 35 percent. The 10 percent nighttimetraining factor at SBMR is lower than the more typical 15 percent factor that occurs at most Armyinstallations. The increase in nighttime noise generation may result in an increase in noise complaintsfrom surrounding communities.Although the numerical increase in noise levels within the cantonment area at SBMR would be small,existing noise levels already represent a significant impact. Therefore, noise from increased ordnanceuse under the Proposed Action would remain a significant impact on people residing on or working atSBMR.Additional Mitigation 1: Although there are likely no mitigation measures that are available to reducethe identified significant impacts to a level below significance thresholds, certain mitigation measuresmay be available to reduce these identified impacts. Potential mitigation measures for identifiedimpacts to the local noise environment include the following:• The Army routinely evaluates training techniques, scheduling, and location to reduce overallnoise impacts at SBMR. In these evaluations, the Army considers the benefit of timingrestrictions on training and moving certain training activities to PTA.• The Army proposes to provide noise-insulating measures whenever new buildings are constructedor existing buildings are renovated, such as modifications to window materials and coolingsystems to noise-sensitive land uses that are or that may become exposed to Zone II and Zone IIInoise conditions.Significant Impacts Mitigable to Less Than SignificantImpact 2: Noise from ordnance use. There would be a significant but mitigable noise impacts at PTAwhere large caliber weapons firing and explosives use would result in Zone II noise contours thatFebruary 2008 5-60 2/25th SBCT Final EIS