AgdaPkt 2010-01-25 clsd and regular

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6.2A Page 56 less-than-significant levels. Impacts on recreational facilities would be similar to those resulting from the Project because establishing required construction staging areas along the right of way would likely result in impacts at some parks where the right of way provides insufficient space for staging. While the number of recreational facilities affected would be similar to the proposed Project, facility replacement as mitigation would prevent the permanent removal of any recreational facilities, 'and similar to the proposed Project would not require long-term closure of recreational facilities. Because the Southern Alignment Alternative would rely on the continued use ofBDPL Nos. 1 and 2 across San Francisco Bay, these facilities would not be decommissioned under this alternative. The SFPUC determined, through engineering studies completed by PG&E Engin.eering Systems and OP AC Consulting Engineers, that BDPL Nos. 1 and 2, the Bay Division system's two oldest pipelines, would require several repairs and seismic upgrades. In particular, these reports indicated that portions of the pipelines, bridge, and trestles that support the pipeline as it crosses San Francisco Bay at Newark Slough and the Dumbarton Crossing may be damaged following an earthquake. Keeping this segment of BDPL Nos. I and 2 in service would require modifications to its supports. SFPUC would need to improve the bridge by strengthening bolted connections, replacing counters, and adding steel straps and fiber wrapping to concrete columns. Wooden trestles would be improved by removing bolts and filling the holes with material to resist deterioration. In addition, photographic investigations show that the interior pipeline walls in several areas of BDPL No.1 have suffered advanced pitting, or narrowing of the walls, resulting in structural degradation. Because repairing future leaks would likely require a pipeline shutdown, several short pipeline segments would likely be replaced under this alternative to improve their reliability. Also, ground shaking could damage BDPL Nos. 1 and 2 in the area ofPulgas Tunnel Portal, where parts of the pipeline are aboveground and are supported by metal trusses. Several pipeline connections in this area would need to be modified with expansion joints. Finally, the ongoing inspection and maintenance program for BDPL Nos. 1 and 2 would need to be expanded to include temporary repairs, including painting, rust removal, timber and walkway repairs, and rivet, bolt, and brace replacement. In summary, because this alternative would not require shafts and a tunnel under San Francisco Bay, it would avoid the noise and vibration impacts associated with hauling the large volumes of excavated material that would be produced during shaft and tunnel construction. This alternative also would avoid the decommissioning impacts on a historic resource by continuing to operate BDPL Nos. 1 and 2 between the Newark and Ravenswood Valve Lots. This alternative could achieve the SFPUC's Project objectives, including meeting estimated 2018 average annual demand and replenishing local reservoirs. While the Southern Alignment Alternative would avoid the environmental impacts associated with constructing the shafts and tunnel, the expanded m.aintenance of the aging BDPL Nos. 1 and 2 would result in potentially significant environmental impacts. . .... .".Although:thhf alternative :would'irieettheSFPUC's'Project"objectives~.the'Coiriinissiori."rejects ...:..... .... the southern alignment alternative as infeasible because it: would result in increased environmental impacts; require higher construction costs; disrupt more residential and commercial areas in comparison to the proposed Project; require more maintenance because of its greater length; decreases delivery reliability because it has more above-ground pipes~ trestles, and retains BDPL Nos. 1 and 2, which are also more vulnerable to earthquake damage; and results in more above-ground pipes and other facilities, which pose security issues. VI.. STATEMENT OF OVERRIDING CONSIDERATIONS 46