FREMONT -- Construction crews have begun prep work to seismically upgrade water pipes near dozens of south Fremont homes, and even residents annoyed by the extra noise and dust are willing to live with the construction that will replace aging pipes that cross the Hayward fault.

"I'd rather they do the work now and do it properly, so there are no issues later," said Mandy Fong, a homeowner living near the construction site at the Mission Boulevard-Interstate 680 interchange.

The $92 million project aims to replace and retrofit a pair of pipes installed decades ago. The pipelines run 2,100 feet, or about a third of a mile, underneath Mission Boulevard and I-680, going northeast from Crawford Street in the Warm Springs district to the intersection of Tissiack Way and Paseo Padre Parkway in the Weibel neighborhood.

Those pipes connect to others that run south, delivering water to Milpitas and San Jose. Two other Fremont pipelines, which have not been upgraded, run westward and connect to pipes along the Peninsula. Plans are to add a new fifth pipeline that will run parallel to those.

The project is part of the $4.6 billion Hetch Hetchy Water System Improvement Program, which is operated by the San Francisco Public Utilities Commission.

The system delivers water to 2.6 million Bay Area residents through a maze of pipes that stretch from Hetch Hetchy Reservoir in Yosemite National Park through the San Joaquin Valley, southern Alameda County, the South Bay, the Peninsula and San Francisco. The utility's infrastructure improvement program has completed 59 projects -- and started 17 others -- throughout Northern California since 2002.


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"The United States' infrastructure is very old and needs replacing," said Daniel Jaimes, a PUC spokesman. "Our infrastructure passes through quake faults, which is why we are upgrading it."

Since late autumn, nearly 100 workers have begun prep work at the Fremont site, including the installation of sound walls to minimize noise pollution for residents, Jaimes said.

Major work on the two pipelines, which cross the Hayward Fault, may start as soon as mid-March. Officials say they feel an extra urgency to get started because the Hayward Fault has caused a major earthquake, on average, about every 140 to 160 years for the past 1,800 years. The last time that happened was in 1868 -- 145 years ago -- when a 7.0 magnitude quake centered in Hayward killed dozens of people, according to the U.S. Geological Survey.

PUC officials say they plan to use new technology to prevent the pipelines from breaking during a major quake.

The first pipe, which agency officials call "Bay Division Pipeline No. 3," is 78 inches in diameter and was installed in 1952. It will be replaced with a new pipe featuring seismically fortified parts designed by URS Corp., a San Francisco engineering company, and recently tested at Cornell University, said Bryan Dessaure, the project's manager.

The new pipeline will be covered with a specially made concrete device called an "articulated box," which has been separated into different segments, allowing for gaps of space between each part of the box, Dessaure said. "Each segment will have the ability to rotate and move individually during a quake while protecting the pipe inside," he said. "It acts as a type of buffer."

Pipeline No. 4 is 8 feet in diameter and was installed in 1973. It will be retrofitted but not replaced, agency officials said.

The Fremont project's construction is expected to be completed by December 2014, Jaimes said. "This project will help us avoid major damage to these pipelines during an earthquake and will work to make our water delivery highly reliable afterward," he said

Contact Chris De Benedetti at 510-353-7011. Follow him at Twitter.com/cdebenedetti.