SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental ConsequencesBlank ammunition and ground-based smoke generating items are the only types of ordnance thatwould be used at DMR. Small arms firing with blank ammunition can produce relatively high peaknoise levels at distances of up to 3,000 feet and might remain audible at distances of up to 1.5 miles.The 1/8 second Lmax noise level from blank ammunition is typically about 71 to 78 dBA at 2,000feet and 50 to 57 dBA at 1 mile. Noise levels from firing blank small arms ammunition typically dropbelow levels that cause substantive annoyance at distances of 2,500 to 3,000 feet. The closestresidential areas are more than 2 miles from the areas where blank ammunition would be used atDMR. Noise effects from ordnance use at DMR would be less than significant.Blank ammunition, SRTA, and various pyrotechnic devices are the only types of ordnance items thatwould be used at KTA. Only blank ammunition is used at KLOA. The closest residential areas areabout 1 mile from the areas where training ammunition would be used at KTA. Noise effects fromordnance use at KTA would be less than significant.Noise from military vehicles. Tactical and support vehicles would travel within SBMR during militarytraining exercises. Vehicles would also travel from SBMR to other installations in support of trainingexercises at those installations. Vehicle convoys using public roads on Oahu are limited to no morethan 24 vehicles in a group. Vehicles within a convoy group (also called convoy serials) typically arespaced about 165 to 330 feet apart and are timed at least 15 to 30 minutes apart. These convoyprocedures prevent situations where convoy vehicles dominate local traffic flow for substantialperiods of time. Instead of creating conditions where military vehicle traffic dominates traffic noiseconditions for a noticeable amount of time, convoy procedures result in noise from convoy trafficoccurring as a sequence of multiple individual vehicle pass-by events within a background of normaltraffic noise conditions.Noise data are not readily available for most military vehicles, and noise data specific to the Strykervehicle are not yet available. Noise data for heavy construction equipment provide some generalguidance regarding expected noise levels from military vehicles. Vehicle noise generation equationsused in highway traffic noise models provide additional useful noise estimates for various types oftrucks and passenger vehicles. The Bradley Fighting Vehicle is a tracked vehicle that has a largerengine (500 horsepower) and is heavier (25 to 33 tons) than the Stryker (which has a 350 horsepowerengine and weighs 19 to 20 tons). Drive-by noise data for the Bradley Fighting Vehicle can be used asan upper limit for the expected noise levels from wheeled military vehicles.Noise levels generated by the Stryker are expected to fall between those of multi-axle heavy trucksand those of the Bradley Fighting Vehicle. This indicates that noise from a Stryker vehicle would beexpected to be within noise levels of existing Army vehicles. The number of military vehiclesassigned to the transformed 2nd Brigade at SBMR would increase by slightly more than 52 percent.Most of the added vehicles would be Strykers, but 50 military vehicles of other types also would beadded. Each of the 12 subordinate commands based at SBMR has its own vehicle fleet.The total government-owned vehicle fleet based at SBMR has not been inventoried, but it exceeds2,000 vehicles. Stryker vehicles would account for no more than 12 to 15 percent of the total militaryvehicle fleet based at SBMR. Military vehicle traffic, dominated by HMMWVs, light trucks, andmedium trucks, would be expected to produce noise levels comparable to normal highway traffic thathas a high fraction of medium and heavy trucks. Noise levels from individual vehicle pass-bys wouldbe comparable to noise levels generated by typical highway truck traffic. The Stryker vehicle isexpected to generate peak drive-by noise levels a few decibels higher than levels produced by typicalmulti-axle heavy trucks.February 2008 5-62 2/25th SBCT Final EIS