New Calaveras Dam: Enough Soil and Rock to Fill Levi’s Stadium Four Times

Crews working on the project to build a new dam at the Calaveras Reservoir moved enough rock and soil to fill Levi’s Stadium from top to bottom four times. That incredible visual is one of the many statistics that illustrates the size and scope of the SFPUC’s efforts to build one of California’s newest dams. 

The Calaveras Dam Replacement Project is the largest project of the $4.8 billion Water System Improvement Program to repair, replace, and seismically upgrade key components of the Hetch Hetchy Regional Water System. The restoration of Calaveras Reservoir to its historic water levels makes the water supply for 2.7 million SFPUC customers in four Bay Area counties significantly more reliable. This is particularly important in times of drought or when Hetch Hetchy supplies are unavailable. Calaveras Reservoir, when full, can store 96,850 acre-feet, or 31 billion gallons of water.

Calaveras Dam Replacement, gravel for stilling basin

Through design, planning and construction, it has taken thousands of hours and more than 20 years to complete the upgrades to the Calaveras Dam.

Last fall, the earth and rock fill dam was rebuilt completely to its full height of 220 feet, marking the finish of the dam construction portion of the project. For the past several months, crews have constructed access roads, automated instrumentation and controls, restored the site, and placed rock slope protections, to fully restore the site and complete the project. 

The new Calaveras dam is composed of seven zones of different materials, with the majority of the earth, rock, sand and clay used for the structure being sourced from onsite. Constructed like a seven-layer cake turned on its side, the dam took two years to construct. The new dam is located directly adjacent to the old dam, and has been built to withstand a 7.25 magnitude earthquake on the nearby Calaveras Fault.

Crews pour concrete on the spillway, final footing floor the wall.

Crews working on the Calaveras Dam Replacement Project moved about 12 million cubic yards of earth and rock to construct the new dam. Of that total, roughly four million cubic yards of material was used for the new dam, while the remainder was placed in other areas on site. The project has moved enough rock and soil to fill Levi’s Stadium from top to bottom four times.

Construction on the Calaveras Dam Replacement Project began in 2011. More than 1,600 workers performed over 1.5 million hours of work on the project. Apprentices (or entry-level workers) on the Calaveras Dam project worked more than 180,000 hours.