T.F. Green Airport Improvement Program - FEIS Chapters - PVD

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) EvaluationComments received during both the agency and public scoping meetings noted that the day-night noise contourrepresented average annual noise conditions and did not adequately represent individual noise events such astaxiing or noise associated with a particular type of aircraft. To address agency and community concerns, the FAAdetermined that additional noise metrics would be added to the noise analyses conducted for the FEIS. Additionalnoise metrics are used to further describe aircraft noise levels for specific noise-sensitive locations and to assist publicunderstanding of the noise impacts. These metrics provide information that the DNL metric does not, such as thetime that a particular location experiences noise above a specified level and the maximum level at each of the sites.The Time-Above (TA) metric is given in terms of the total number of minutes. The maximum noise level (L max) helpsto characterize the magnitude of the noise event, but does not provide information regarding the duration of orcumulative exposure to the noise. These noise metrics were modeled using the same input data used to develop thenoise contours. It is important to note, that these metrics are used to provide additional details of the noiseenvironment and are not assessed to determine impacts since there are no applicable FAA criteria or standards.5.3.3 MethodologyFAA Order 1050.1E specifies a number of requirements, including which noise models are acceptable, whatconstitutes significant impact, and when additional noise analyses or metrics may be used. This sectionsummarizes the methods that were used to estimate noise from various noise sources. Refer to Appendix F.1, NoiseAssessment Methodology and INM Inputs, for further details on the noise assessment methodology. Information onacoustics and noise terminology is provided in DEIS Appendix F.1, Introduction/Acoustics and Noise Terminology.5.3.3.1 Models Used for this AnalysisFAA’s INM is the preferred model for assessing the noise impacts of airport development and determining thesignificance of changes in exposure. For the FEIS environmental consequences analysis for Alternatives B2and B4, the noise model was re-run with fewer forecasted No-Action Alternative annual operations and theIncremental Build Forecast (Tables 5-3 and 5-4). The latest version, INM Version 7.0b, was used to produce DNL75 dB, DNL 70 dB, DNL 65 dB, and DNL 60 dB contours as well as modeled levels at specific noise-sensitivesites. Figures 5-3 through 5-6 show the model flight tracks for Alternatives B2 and B4. The Traffic Noise Model(TNM) which is required for the evaluation of vehicular traffic changes was used to assess the roadway noiseimpacts and a spreadsheet model approved by the FAA for use on this project 283 was used to assess the noiseimpacts from the proposed Integrated Cargo facility. Refer to Appendix F.1, Noise Assessment Methodology and INMInputs, for further details on the INM model inputs and assumptions.5.3.3.2 Direct and Indirect Impacts MethodologyThis noise assessment evaluated three sources of noise to understand complete noise exposure resulting fromthe Improvement Program within the Noise Study Area (shown on Figure 4-1). The three sources include:• Noise associated with aircraft operations (or flights); 284• Cargo aircraft ground operations (for example, taxiing, idling, and ground power units); and• Traffic noise from vehicles (including trucks and cars) on off-Airport roadways.For 2015, two sources of program-related (resulting from Alternatives B2 and B4) noise were analyzed for theimpact assessment: aircraft noise from flight operations and traffic noise from the off-Airport roadway283 FAA Office of Environment & Energy, Approval of Spreadsheet Methodology, June 12, 2008.284 An operation is defined as a takeoff or a landing.Chapter 5 - Environmental Consequences 5-15 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH05_Environmental_Cons_JUL_2011.doc