AgdaPkt 2010-01-25 clsd and regular

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6.2A Page 52 water supply needs through the year 2018, which is the SFPUC's planning horizon for the WSIP. Existing facilities do not and would not reliably or adequately serve current and future populations based on current per-capita levels of use and the potential for a prolonged drought. For instance, jurisdictions served by the SFPUC, specifically the cities of Foster City and San Mateo, have adopted Statements of Overriding Considerations for their general plans because water supply constraints were considered to be significant and unavoidable impacts in approving new development. Additionally, the current BDPL system does not provide sufficient redundancy to ensure uninterrupted water delivery ifboth planned and unplanned outages occur simultaneously. Thus, one Project objective is to contribute to meeting the estimated average annual demand of up to 300 mgd by 2030 under the conditions of one planned shutdown of a major facility for maintenance concurrent with one unplanned facility outage caused by a natural disaster, emergency, or facility failure or upset. The No Project Alternative would not address the need to ensure continuation of service by providing seismic reliability, flexibility, capacity, and redundancy. These system attributes are needed to address required shutdowns for inspection, repair, rehabilitation, or replacement of pipeline sections, as well as reliable replenishment of local reservoirs. Alternative 2: No Project Variant The No Project Variant Alternative would rely on the continued use ofBDPL Nos. 1 and 2 across San Francisco Bay; thus, these facilities would not be decommissioned under this alternative. Each pipeline would be vital to continued water conveyance and no additional pipeline or Bay Tunnel would be constructed. However, in an effort to preserve the physical and operating integrity of the existing system, planned and coordinated repairs and upgrades to existing facilities would be required. The SFPUC has determined, through engineering studies completed by G&E Engineering Systems and OPAC 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 ofBDPL Nos. 1 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 . s~lort pipe.l~~e s.egm~l:1tsd' ~()~l~Ji);{~~y ~~..r~pl~(;~d ~Ilcl~r ~i.~Cll~~J:11Clti.,,~..t()..i.~PJ;<>.y.e.$.e.j.r... .. .... ......... . . . re iability."Also, groun "shaking 'could damageBDPL Nos'. land 2 in the area 'Of'PulgilS Tunn.el.... 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. However, the No Project Variant would not be without potential significant impacts. Even with planned repairs and improvements) the existing pipelines would continue to age, thereby increasing the chances of pipeline failure. This alternative would also leave SFPUC water customers vulnerable to the impacts of a severe drought or a catastrophic interruption of an 42