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

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluation5.3 NoiseIn accordance with FAA NEPA Orders, this section provides an overview of the impact analysis for changes innoise levels as a result of the proposed Alternatives B2 and B4 when compared to the No-Action Alternative.Section 5.4, Compatible Land Use, discusses noise impacts in terms of the amount of incompatible land area (inparcels and acres), specifically residential land uses.5.3.1 Regulatory ContextThe FAA is the primary agency responsible for regulating the noise environment, as specified by statutes andtheir implementing regulations. The FAA regulations, at 14 CFR Part 150, identify land uses normallycompatible with various exposures of individuals and properties to noise. 2795.3.2 Significance Threshold and Additional AnalysesThe noise analysis considers the impacts of Alternatives B2 and B4 as defined by the FAA’s thresholds ofsignificance, and also conducts additional noise analyses to gain a fuller understanding of the noiseenvironment.5.3.2.1 Finding: Significant Noise ImpactsThe significance threshold for changes in noise, in accordance with FAA Order 1050.1E, is when an action,compared to the no action alternative for the same timeframe, would cause noise-sensitive areas to experience anoise increase of at least DNL 1.5 dB at or above DNL 65 dB (Table 5-6). Table 5-7 lists the FAA-defined noisesignificance thresholds as well as slight to moderate levels of noise impact.Table 5-7DNL Noise Baseline Exposure Compared to Alternative ExposureDNL 65 dB or higher DNL 60 to 65 dB DNL 45 to 60 dBMinimum Change in DNL with Alternative 1.5 dB 3.0 dB 5.0 dBLevel of Impact Significant Slight to Moderate Slight to ModerateSource: FAA 1050.1E and the Environmental Desk Reference for Airport Actions.At the same time that the FAA revised the No-Action Alternative operations forecast, the FAA determined itwas prudent to use the most recent version of the INM to assess project-related noise impacts. The FEIS analysisutilizes the INM Version 7.0b, and also provides more accurate noise modeling data by slightly modifying theINM aircraft input types to provide more up-to-date information. These model input changes resulted inincreased modeled noise from these aircraft, resulting in larger FEIS noise contours when compared to the DEISLevel 6 contours and thus additional noise impacts under the No-Action Alternative and Alternatives B2 and B4conditions. The change from the DEIS to the FEIS analyses is due to the change in operations, the utilization ofthe most recent version of the INM noise model from version 7.0a to 7.0b, and a small change in model inputs.Under Alternative B2, in 2015, no housing units and no people are projected to experience a significant increase279 14 CFR Part 150, Airport Noise Compatibility Planning.Chapter 5 - Environmental Consequences 5-13 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH05_Environmental_Cons_JUL_2011.doc