News and Events

Calaveras Dam Replacement Spillway Completed

Wednesday, 11 May 2016

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SAN FRANCISCO, California — On April 18, 2016, the Calaveras Dam Replacement Project (CDRP) reached a landmark point with the official completion of the concrete spillway. The dam and adjacent Calaveras Reservoir is owned by the San Francisco Public Utilities Commission (SFPUC) and was originally constructed in the early 1920’s.

The replacement Calaveras Dam is the largest Bay Area reservoir project in 20 years, replacing the existing dam with a seismically-sound dam. The new dam will be able to withstand up to a 7.25 earthquake – a necessity with the Calaveras fault sitting less than 2,000 feet away from the dam.

Approximately 50,000 cubic yards of concrete was placed for the spillway, which is 1,550 feet long, 60 to 80 feet wide, and 20 to 45 feet deep capable of handling a flow of 45,000 cubic feet per second.

Kleinfelder is part of the Construction Management team led by Black & Veatch and is responsible for Quality Assurance and Quality Assurance sampling and testing, checking the contractor’s quality control (QC) program related to all construction materials and procedures. These include concrete and reinforcing steel, welding of large diameter steel pipe, lining inspections of the steel pipe, geotechnical testing of embankment fill materials, and testing for grout injection of the dam grout curtain.

Kleinfelder is also the lead monitor for the naturally occurring asbestos (NOA) observations.

The spillway completion has garnered wide media attention in the Bay Area, including news coverage by NBC and CBS - KPIX, and a front page piece in the San Jose Mercury News.

The San Francisco Public Utilities Commission (SFPUC) also uploaded a time-lapse video of the concrete spillway’s four year construction to their YouTube channel.

The video depicts the excavation of 7 million cubic yards of earth in about two minutes over the four-year construction period.

 “The geological setting, presence of naturally occurring asbestos (NOA), and maintaining flexible start times have made the Calaveras Dam Replacement Project one of the most challenging projects that any of the Construction Management team members can recall,” said Glen Gorski, Kleinfelder’s Lead Quality Assurance Inspector for the project. “Anchoring 50,000 cubic yards of concrete to the side of a mountain is one of those engineering accomplishments that really stands out.”

The project is slated for completion in late 2018 or early 2019. Construction of the 220-foot-high earthen dam embankment will include moving an additional 3.5 million cubic yards of earth.

The Calaveras Dam Replacement Project is the largest project of SFPUC’s $4.8 billion Water System Improvement Program (WSIP). Launched in 2002 and now more than 90% complete, the WSIP will repair, replace, and seismically upgrade key components of the Hetch Hetchy Regional Water System.

The new dam is the same size/height as the old dam, just engineered better.

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