URS CORPORATION 2 - 2002 - Laserfiche WebLink

Home Browse Search

.' URS February 7, 2001 Jeffry S. Rice, AICP Principal Planner City of Santa Ana Planning and Building Agency Number 20 Civic Center Plaza Santa Ana, California 92702 SUBJECT: INDEPENDENT TECHNICAL REVIEW OF THE CENTERLINE PROJECT SUPPLEMENTAL DRAFT ENVIRONMENTAL IMPACT STATEMENT / REVISED ENVIRONMENTAL IMPACT REPORT (S/R DEISIR) NOISE IMPACT ANALYSIS (DECEMBER 2000) Dear Mr. Rice: The City of Santa Ana retained URS (URS) to evaluate the Noise and other relevant sections of the subject Supplemental/Revised environmental documentation prepared for the Orange County CenterLine Project and report its findings to the City. URS has conducted an Independent Technical Review of the Noise/Vibration Section and portions of other relevant sections contained in Volume I and Volume II of the SIR DEIS/R for the CenterLine Project. Our evaluation of the document was limited to the project and its potential effects occurring within the City of Santa Ana. This letter represents our Report on the SIR DEISIR. Unless specifically modified herein, the recommendations contained in our October 8,1999 evaluation of the previously issued DEIS/R remain applicable. The following comments apply primarily to the SIR EIS/R: Summary of URS Findings I. The noisc mitigation measures for elevated guideway elements primarily take the form of on- structure, sound-absorptive noise barriers. For Street Level segments, non-absorptive barriers (soundwalls) are recommended where practicable. 2. Unlike noise mitigation measures discussed in the previously circulated DEIS/R, there is a commitment in the SIR DEISIR to incorporate reasonable and feasible noise mitigation into the project design or adopt the mitigation measures (Section 4.10.7). Reasonable and feasible noise abatement/mitigation measures (in the form of sound walls) are recommended for noise-sensitive uses that are "moderately" impacted as well as for sensitive uses that are "severely" impacted. Where sound walls would not be effective or would not be physically feasible for "severely" impacted areas, the document states that building modifications would be implemented that will reduce the interior noise levels to acceptable levels. However, no mitigation by building modification is recommended for "moderately" noise impacted areas where mitigation by sound walls is nol feasible. This would leave 45 residential units and two hotellmotellocations as moderately noise impacted if the SRA or IAA alignments were to be implemented in Santa Ana. We commented on this issue of partial mitigation in our previous evaluation provided to the City URS Corporation 2020 East First Street, Suite 400 Santa Ana, California 92705 Tel: 7146.835.6886 Fax: 7149.667.7147 T:\200 1 "--')7 -09961035 _02 CcntcrLinc\tepon.doc