2017-046 - Approving Addendum Nos. 1 and 2

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F31J� OCTA ISanta Ana/Garden Grove Streetcar Project Cultural Resources Technical Nlamo Update physical alterations with surrounding historical properties, the onlypotential for an adverse impact to occur during construction would result from indirect vibration effects thatcause physical damage to historic structures. Thep rope rtiesin thee xpanded APE would beset back ata distance far enough from construction activitythat the vibration levels would be belowthe FTA threshold for historic structures. As an outcome of furthering the projectdesign and value engineering for the LPA, OCTAhas determined that more efficient bridged esignoptions could be implemented at the Westminster Avenue location. This resulted in the selection of a bridge design that is more typical of rail crossings that exist throughout southern California. The proposed modified bridge design would include a concrete cast -in-place boxgirder bridge structure rather than the proposed tied arch structure (Figure 3, Figure 4). As noted in the 2014 cultural resources evaluation and in the updated Visual Impact Analysis (VIA)conducted in 2016 to address the bridge modifications, the visual quality of the Westminster Bridge is considered moderate low to moderate (see Appendix F). The proposed bridge area is surrounded bynon-historic period commercial and industrial properties, and would notcause a change in the area's visual characterand would not be considered a visual intrusion to the surrounding area. Therefore, modifications to the proposed Westminster Bridge would have no adverse effect on historic properties. The two minordesign modifications thathave the greatest potential to effect historic properties are the proposed bridge adjacent to the Old Pacific Electric Santa Ana River Bridge and the relocation ofTPSSs. As orig inallyproposed in 2014, a single-track bridge would be constructed south of the historic Pacific Electric Santa Ana River Bridge. The proposed modification includes construction of a double -track bridge north of the historic bridge. The updated 2016 VIA determined thatno news ignificantvis ual impacts and no increase in the severity of an impact would result as compared to the originally approved bridge (Appendix F). Currentviews of the bridge are limited to long range views along 5m Street to the south and Fairview Street to the north and east. Unobstructed views of the bridge can only be seen from the Santa Ana River Trail, which is open to pedestrians, bicycles and horses. The existing bridge would remain in place and a new bridge would be constructed to the north of the existing historic bridge. The proposed projectwould require the alignment to be grade separated from the Santa Ana River Trail on both the eastand west sides of the river. The grade separation would occur on the backside of the flood control levee to avoid impacting the western abutment of the historic bridge. The visual elements of the historic bridge would be minimally affected because the materials used forthe newparallel structure would differfrom the historic materials. The feature thatqualifies the Old Pacific Electric Santa Ana River Bridge as a historic property, the Pegram truss, is defined byits features of distinguishable geometric design, with the posts arranged at increasing anglesfrom the vertical chords from the center of the truss towards the ends. These features are most distinguishable atthe top of the bridge span. Because the views of the existing bridge would onlybe partiallyobstructed atthe base of the bridge and to a limited group of viewers, the proposed new bridge would nots ubstantially impair the historic bridge's activities, or views of the Pegram truss architecture. The proposed new bridge will notadvorsely affectthe integrityor features and attributes that qualifythe Pacific Electric Santa Ana River Bridge as a historic property. Thus, there would be no adverse effects resulting from the July 8, 2016 1 13