2017-046 - Approving Addendum Nos. 1 and 2

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OCTA I Santa Ana/Garden Grove Fixed Guideway Project FNNoise and Vibration Technical Analysis Re-evaluation in Support of Minor Design Modifications Memo Date: Monday, July 25, 2016 Project: Santa Ana/Garden Grove Fixed Guideway Project To: Mary Shavalier/Program Manager, OCTA From: Keith Lay/Senior Air Quality and Noise Specialist, HDR Subject: Noise and Vibration Technical Analysis Re-evaluation in Support of Minor Design Modifications HDR performed a re-evaluation of noise and vibration technical analysis on the preliminary engineering (30% design) for the Orange County Transportation Authority's (OCTA) Santa Ana/Garden Grove Fixed Guideway Project (Project). The purpose of this analysis was to identify any changes to noise or vibration effects that were previously disclosed in the adopted Environmental Assessment/Finding of No Significant Impact (EA/FONSI) (2015), due to several design modifications with the advancement of engineering since the Project (and conceptual design) was approved in 2015. This memorandum presents the results of the noise and vibration technical analysis re- evaluation of the proposed minor design modifications. The results of this analysis are based on an independent assessment and review of the currently proposed minor design modifications as compared to the approved Project (Locally Preferred Alternative, 2015 LPA) that was the basis of evaluation in the February 2012 Noise and Vibration Technical Report (URS Corporation). The prior noise and vibration report was prepared by URS Corporation following the Federal Transit Administration's (FTA) Noise and Vibration Manual (FTA 2006). The prior report was included as Appendix J to the Environmental Assessment/Environmental Impact Report (EA/EIR) prepared and approved in 2015. The methodology of the FTA Noise and Vibration Manual was also followed for this re-evaluation. The outcome of this noise and vibration re-evaluation of proposed minor design modifications is that the recommendations have been incorporated into the project in the form of design features. Incorporation of these design features would attenuate noise and vibration levels at the few locations potentially affected by the minor design modifications along the project alignment, such that no new significant impacts and no increase in the severity of an impact would result as compared to the originally approved project and as evaluated in the 2015 EA/EIR. Project Background Construction and operation of the Project (the adopted LPA), based on conceptual engineering, was approved by the Federal Transit Administration (FTA) in a Finding of No Significant Impact (FONSI), dated March 10, 2015, pursuant to the National Environmental Policy Act (NEPA). The approval of the project was based on the findings of the Revised Environmental Assessment 1