We have Reached the Dam Foundation.

We continue digging away here at the Calaveras Dam Replacement Project. In July we reached a milestone of excavating the first million cubic yards of earthen material. This week we have reached another important place---the foundation of the dam. The foundation of the new dam will be on bedrock and is located almost 225 feet below the top of the existing dam. The existing dam still holds back the Calaveras reservoir and, as expected, we encounter some minor seepage at the bottom that is controlled by pumping to our storm water treatment system. This is just the first phase of excavation work on the east side of the dam foundation. The west side of the dam foundation will be done later as we prepare that surface for the installation of the new dam’s spillway. It is important to note that this significant construction project is taking place while the Calaveras reservoir remains in service as an important source of drinking water for our Bay Area customers.

View of excavated area of dam foundation

For more project info, contact us at our 24 hour answer line at (866) 973-1476 or email mle@sfwater.org

Ready for Rains

It’s been wet out there, lately. As the Calaveras Dam Replacement Project begins construction, the team is ready for winter rains. The contractors must be prepared to treat storm water runoff to protect the local creeks. Large areas of exposed ground created as part of construction have the potential to erode soils and impact the water quality downstream. The project has installed a treatment system to protect the local creeks. The treatment consists of removing any silts and clays that may be eroded from exposed excavation surfaces. The contractor has installed an active treatment system that consists of retention ponds and sand filters to clean turbid waters prior to discharging back to the Calaveras Reservoir. The treatment system is designed to manage a flow up to 2,400 gallons per minute, equivalent to approximately 57 bath tubs filled with water.


The treatment system is prepared to operate around-the-clock for the duration of the four year project. We currently anticipate treating approximately 270 million gallons water. As the project prepares to move over 7 million cubic yards of earth over the next four years, the treatment system and other erosion control features will help maintain the water quality in the Alameda Watershed.


For more info, contact us at our 24 hour answer line at (866) 973-1476 or email mle@sfwater.org