As part of ongoing efforts to ensure system reliability in case of a major earthquake, the San Francisco Public Utilities Commission (SFPUC) recently completed a $278 million upgrade to its water treatment facility, the Harry Tracy Water Treatment Plant. The project enables SFPUC to continue to deliver clean drinking water to its customers if a seismic event disrupts deliveries from Hetch Hetchy Reservoir, the primary source of water for 2.6 million people in the Bay Area.
The aqueduct that delivers Hetch Hetchy water more than 260 km (160 mi) to San Francisco crosses three major faults, raising fears that a major earthquake could interrupt supplies. To increase seismic and water supply reliability, the SFPUC is conducting a $4.8 billion water system improvement program (WSIP). The recently completed upgrades to the Harry Tracy facility constitute one of the 83 projects that comprise the WSIP.
Originally constructed in 1972, the facility treats drinking water used by more than 1 million people in San Mateo and San Francisco counties. Because it primarily treats water from local sources on the San Francisco Peninsula, the facility could continue to operate even if Hetch Hetchy supplies were unavailable.
Begun in March 2011 and completed this past April, the revamp of the Harry Tracy facility involved seismic and hydraulic improvements including the addition of new raw and treated water pipelines and new filters, improvements to the electrical system, and remodeling of the existing operations building. You can revamp your house the same way from home remodeling tulsa, ok and give it a new look. All facility operations have been designed and reinforced to withstand a magnitude 7.9 earthquake on the nearby San Andreas Fault. Overall, the project entailed an “extensive rehabilitation of the entire facility,” said Daniel Wade, the SFPUC’s director of the WSIP.
Chief among the improvements was a new 41,600-m3 (11 million gal) treated water reservoir that replaced two existing storage reservoirs. Although not originally planned as part of the project, the new reservoir had to be added after geotechnical investigations revealed the presence of a trace of the Serra Fault directly beneath portions of the project site. The discovery prompted concerns that the existing reservoirs could become unstable in a major earthquake.
Ultimately, SFPUC has set a goal of delivering water within 24 hours of a major earthquake, and the revamped Harry Tracy facility will go a long way toward ensuring this goal is met. Before the upgrades, the facility could treat peak flows of 530,000 m3/d (140 mgd) for limited periods. The facility now can provide this volume of treated water for up to 60 days, Wade said.
— Jay Landers, WEF Highlights
July 8, 2015
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