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

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluation6.21 Alternative B2 MitigationMitigation measures were identified for the T.F. Green Airport Improvement Program where eitherAlternatives B2 or B4 would result in significant impacts that are either permanent or temporary in nature(occur during construction). The results of the environmental consequences lead the FAA to identifyAlternative B4 as the Preferred Alternative, and RIAC has indicated a preference for Alternative B4 as itsProposed Action (see Chapter 3, Alternatives Analysis).Mitigation measures considered in this chapter of the FEIS focus on design measures to avoid or reduceimpacts, and measures to replace or restore the functions and values of lost resources. Section 6.2, Noise throughSection 6.20, Mitigation Implementation and Monitoring, focus on Alternative B4. This section includesAlternative B2 mitigation measures for comparative purposes only. Tables 6-1 and 6-2 also provide acomparison of Alternative B2 and B4 mitigation measures.6.21.1 NoiseAlternative B2 would require the acquisition of several properties due to the Fully Relocated Airport Road andassumes full participation in the clearing of the Runway 23 RPZ, neither of which are part of Alternative B4.These two items reduce the number of residential properties to the north of the airport under the noise contoursand thus reduce the numbers of properties affected by Improvement Program-related airport noise underAlternative B2. Thus, Alternative B2 would require fewer homes to be mitigated from aircraft noise whencompared to Alternative B4.6.21.1.1 Mitigation for Significant Noise Impacts for Alternative B2The number of homes exposed to noise levels greater than DNL 65 dB and eligible for sound insulation wouldbe approximately 10 percent lower in Alternative B2 than for Alternative B4 due to the land acquisition for RPZclearing and Fully Relocated Airport Road as noted above. The number of homes requiring mitigation due toexposure to significant impacts (for residences located at or above DNL 65 dB that would experience a noiseincrease of at least DNL 1.5 dB when compared to the No-Action Alternative) with Alternative B2 would beapproximately half that of Alternative B4.In 2020, Alternative B4 would expose two non-residential noise sensitive sites to a significant noise impact andAlternative B2 would expose none to a significant noise impact. (One of the two non-residential noise sensitivesite (Baha’i Faith) was already sound insulated as part of a previous sound insulation effort under the Part 150NCP and, therefore, would not require additional mitigation.) Almost twice as many homes would be exposedto a noise increase from traffic impacts in Alternative B2 when compared to Alternative B4. Both Alternative B4and Alternative B2 traffic noise impacts could be potentially mitigated with up to six noise barriers, howeverhalf of these for Alternative B2 would not be cost effective based on the RIDOT criteria described inSection 6.2.4.4, Install Noise Barriers or Berms on Main Avenue. For Alternative B2, through 2025, a total of zerohousing units would be newly eligible for Project-related noise mitigation (sound insulation) due to significantnoise impacts (no additional units in 2015, 2020, or 2025) compared to 24 units total under Alternative B4.Chapter 6 – Mitigation 6-44 July 2011\\Mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH06_Mitigation_JUL_2011.doc