AgdaPkt 2010-01-25 clsd and regular

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6.2A Page 27 The proposed Project includes two decommissioning variants for portions of BDPL Nos. 1 and 2 Historic District (HR-l). The "decommission in place" option would result in significant impacts on HR-l after the BDPL No.5 warranty period expires when the Bay crossing segment of the pipelines would be removed from service. Because the Bay Tunnel would be designed to last for at least 100 years, the pipelines would no longer be used and could eventually fall into disrepair. Although the time frame for this impact could be beyond the life of the proposed replacement tunnel, decommissioning in-place would result in significant impacts because it could cause a substantial adverse change in the historical significance of this historical resource. The impacts from decommissioning would materially impair the characteristics of HR-l that make it eligible for the NRHP and CRHR. . Mitigation Measure CR-4a: If decommissioning in-place is selected for the Bay-crossing reach ofBDPL Nos. 1 and 2~ record all contributors to the BDPL Nos. 1 and 2 Historic District in accordance with Level II of the HABS/HAER standards . Mitigation Measure CR-4b: Develop interpretive materials; install interpretive displays at the Don Edwards San Francisco Bay National Wildlife Refuge and/or the Ravenswood Open Space Preserve Impact CR-5: Construction impacts on unique paleontological resources. The proposed Project would require excavation through rock units that have high potential for containing significant fossiliferous resources from milepost 0.0 to 7.1 (i.e., entire eastern segment) and 7.5 to 13.5 (i.e., most of the eastern portion of the western segment). Because the proposed alignment would be located in high sensitivity areas, construction, including excavation and tunneling, could destroy unique paleontological resources, which would be a significant impact. . Mitigation Measure CR-5a: Conduct construction worker training . Mitigation Measure CR-5b: Suspend Project construction, as necessary; undertake resource salvage operations. Impact CR..6: Construction impacts on human remains. Portions of the pipeline alignment would be constructed within land that has not previously been disturbed, and construction could disturb human remains. Any remains found during construction in the study area would have been interred outside a formally recorded cemetery, and their disturbance would result in a significant impact. . Mitigation Measure CR -1 d would mitigate impacts relating to potential impacts on human remains. Impact HAZ-l: Potentially significant exposure of the public to hazardous building materials caused by demolition activities. Various SFPUC structures and unauthorized encroachments into the right of way would be removed or demolished prior to construction. These encroachments may contain hazardous building materials such as lead-based paint; asbestos-containing materials or electrical equipment containing PCBs; fluorescent light tubes containing mercury; and fluorescent light ballasts containing PCBs. The disturbance of asbestos-containing materials could result in exposing the public or construction workers to airborne asbestos fibers, unless proper asbestos abatement precautions are taken. Similarly, if lead-based paint or other hazardous materials have delaminated or chipped from the surface of the building materials, there would be a potential for airborne particulates to be released unless proper abatement procedures are followed. If the buildings to be demolished contain electrical equipment or lighting with PCBs, leakage could 17