Page 236 - Peterson 85 Years and Going Strong

CALAVERAS DAM REBUILD (2011–2019)
The Calaveras Dam Replacement project began in late 2011 as a four-year, $300 million contract. It is the cor- nerstone of San Francisco’s $4.8 billion improvement program on the Hetch Hetchy Regional Water System.
The Calaveras Reservoir is the Bay Area’s largest drink- ing-water supply, but it had been reduced to 40 percent capacity in 2001 due to seismic concerns. Officials worried that the structure might fail since it is situated within 1,500 feet of the active Calaveras Fault line. The joint-venture team of Dragados USA, Flatiron West, and Sukut Construction began work on it in August 2011. The mammoth project required:
• excavating7millioncubicyardsofrockandsoil
• embanking4millioncubicyardsofmaterial
• constructinga41,000-cubic-yardconcretespillway
• laying6,000linearfeetof78-inchsteelpipe
• tunnelingandconstructinga250-footdeepby30-footwideintaketower
The dam was finally completed on May 28, 2019, with an $823 million price tag. Today, the 210-foot high pyramid-shaped earthen structure is located just downriver and butts up against its ninety-four-year-old predecessor. The reservoir now provides 31 billion gallons of drinking water to 2.5 million residents in Alameda, Santa Clara, San Mateo, and San Francisco counties.
234 | PETERSON: 85 YEARS AND GOING STRONG
Calaveras Dam Rebuild during (top) and after (above)