An Ode to the Calaveras Spillways, old and new

Workers repair original Calaveras Dam spillway in 1939

What is a spillway?

A spillway is an important safety feature on a dam that impounds water behind it to prevent the dam from overtopping and suffering damage during a flood. The spillway is often an open chute or channel that allows water when it reaches a high level in the reservoir to safely bypass the dam and flow downstream without causing any damage to the dam.

History of the Calaveras Dam Spillway
The original spillway on Calaveras Dam was completed in 1925. In 1939, workers had to repair the original spillway after damage was caused by a flood occurred in the Winter of 1937-1938.

Spillway Work Today
Back in March work began on the new spillway. We have made much progress since then to construct the spillway, which will be 1550 feet long. Approximately 40,000 cubic yards of concrete, equivalent to one football field filled six feet deep, is being used to build the structure. All of the concrete is being supplied by our on-site concrete batch plant.
Because of its crucial function in dam safety, it’s important to make sure that the spillway structure stays intact during an earthquake on the nearby Calaveras Fault. So we are drilling anchors, a solid steel rod, about 25 feet into the rock around the spillway to provide support and prevent damage to the structure during any seismic activity.  We are installing 1,825 anchors, that’s a lot of anchors!  The spillway is expected to be completed in mid-2015.

View of the left wall of the new Calaveras Dam spillway. The purple anchor in the foreground will be encased in the concrete slab (foundation) being formed here. The exposed ends of the wall anchors will be encased in a block of concrete as part of the spillway wall.

Aerial view of new spillway taking shape at the left abutment.
Red arrows indicate the top of the spillway.

Neighbors Catch up on the New Irvington Tunnel

Thank you to all of the community members who dropped by the New Irvington Tunnel Open House at the Mission Coffee House last week!  It was really great to see you.  For those of you who weren’t able to attend, here are the highlights as shared by the project team.

• The New Irvington Tunnel Project is currently 95% complete.
• The steel liner of the tunnel has been installed. We are welding and grouting the space between the tunnel lining and the outside of the tunnel to seal the tunnel off from groundwater intrusion.
• The 3.5 mile New Irvington Tunnel will be brought into service sometime this fall 2014, allowing us to take the old tunnel out of service for inspection and possible repairs.
•  Overall project completion is anticipated in fall 2015, soon after we complete site restoration of all of the above ground work.
• The New Irvington Tunnel runs parallel to the existing tunnel (which was built in 1932)  between the Sunol Valley south of Highway I-680 and Fremont, California. It provides a seismically designed connection between Sierra Nevada and Alameda Watershed water supplies and 2.6 million Bay Area customers.

We will be back out with another open house in a about three months, so we hope you can make the next one. 

Neighbors have some tunnel talk at the New Irvington Tunnel Open House

New Irvington Tunnel Project Open House on June 3rd

Construction on the New Irvington Tunnel is nearing completion! We anticipate commissioning the new tunnel sometime this Fall 2014. The new tunnel will provide a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed, providing water to our 2.6 million customers. Work still lies ahead, with project completion expected in mid-2015. 

Join us on June 3, 2014 from 4:30 pm to 6:30 pm at Mission Coffee House (151 Washington Blvd., Fremont CA). The project team will be present to answer any of your questions and discuss what to expect post-construction for our Groundwater Management Plan participants. 

View from inside a section of the New Irvington Tunnel

Alameda County Residents Contribute to 10 Years of WSIP Success

It seems like only yesterday the San Francisco Public Utilities Commission launched the Water System Improvement Program (WSIP). However, April marked the 10-year anniversary of WSIP, and, perhaps it seems like time has flown by since we’ve been busy at work!!  Since the start, 11,000 workers have been employed by the program.

Nearly six million craft hours have been completed on the program to date, which includes 725,000 apprenticeship hours.  Plus, San Francisco and service-area residents have worked 50 percent of those craft hours. In fact, Alameda County residents are responsible for the largest percentage of total hours worked on WSIP out of all the participating counties!

Thanks in part to the hard work of Alameda County residents, the WSIP is now 80 percent complete. The WSIP will ensure the Hetch Hetchy Regional Water System, which serves 2.6 million customers in the Bay Area, will be able to withstand a major earthquake or drought and continue to deliver water to customers.

                       A crew member upgrades the San Antonio Pump Station, a key WSIP project now complete.

Sunol Glen School Students Celebrate Earth Week with Us!

What do ancient shark teeth, wasps nests, and owl pellets have in common? All were on display last week at the Sunol Glen School’s Earth Day Science celebration last week.  We were lucky enough to have been invited to participate, along with other local groups and leaders.  The kids, grades Kindergarten through eighth grade, learned about the importance of building a seismically upgraded replacement dam at the Calaveras Reservoir. Our project Geologist Bradley Erskine showed some fascinating fossils found at the Calaveras site during construction. The biggest hit with the students by far was a prehistoric shark tooth possibly from a Megladon, dating at approximately 20 million years old.  We had a great time answering questions about how water gets to your tap and the importance of the Water System Improvement Program to future generations.

Having met the leaders of tomorrow at Sunol Glen School, we know the future is in good hands! Sunol Glen Schools students proved themselves to be inquisitive and curious scientists at Earth Day on May 2^nd. 

Geologist Bradley Erskine and Natural Resources staffer Amy Dawson share fossil finds from Calaveras Dam to the Sunol Glen School students

Sample fossils of prehistoric shark teeth dating over 20 million years old

Critters, Kids and Parents oh my!! All Tested their WSIP Facts at the Sunol Wildflower Festival

Community members and even an enthusiastic furry friend joined the Water System Improvement Program (WSIP) team to learn about water conservation, local wildlife and the Sunol Valley Watershed at the Sunol Wildflower Festival earlier this month. Visitors to our booth tested their knowledge of WSIP facts by spinning the prize wheel to with fun prizes. In case you missed the Festival, here are a couple of the most challenging questions:
· How many gallons of water does the washing machine use? 55 gallons
· Why would we have injected more than 8 million pounds of cement grout into the New Irvington Tunnel during construction? To seal the tunnel heading off from groundwater intrusion

A special thank you to our partners at the East Bay Regional Park District and Alameda Creek Alliance for hosting this wonderful event.

Our furriest of friends learned about WSIP construction projects in Sunol Valley

WSIP staff quizzed visitors on water topics with the WSIP prize wheel.

Calaveras Dam Welcomes the US Society on Dams Conference

It is fitting that the SFPUC helped host the annual meeting of the United States Society on Dams (USSD) this last week in the same month as the anniversary of the 1906 Great Earthquake and Fire. The group finished their week of technical sessions and presentations on dam safety in extreme events with a field tour of a dam in construction.

That would be our very own Calaveras Dam Replacement Project. The project will construct a new seismically designed earth and rock fill dam right next to the existing, which will be able to withstand the maximum credible earthquake on the Calaveras fault.

The USSD Conference attendees peppered the Calaveras Dam Replacement Project Team with questions.  We appreciate that the SFPUC project team members, the Construction Management team from Black & Veatch, Design team from URS, and the contractor Dragados USA/Flatiron/Sukut Construction shared their experiences with their industry colleagues. 

Then the Calaveras Team returned to the current work at hand, which is continuing the major excavation work on the new spillway and stilling basin, as well as mechanical and electrical improvements to the new intake Tower.

When complete in late 2018, the replacement dam will enable us to bring the Calaveras Reservoir back to historic capacity, storing approximately half of the Hetch Hetchy Regional Water System’s local Bay area water supply.

This somber anniversary for the 1906 Great Earthquake reminds us to ensure our families are prepared for the next big earthquake. Visit 72hours.org, or http://www.redcross.org/ca/san-francisco/ to learn more. 

 SFPUC Project Manager Susan Hou discusses the critical upgrades to the Hetch Hetchy Regional Water System

Project Manager Alberto Benlloch from the joint venture of Dragados USA/Flatiron/Sukut Construction points out to the tour the excavation work to-date of over 4 million cubic yards of material

Aerial view taken on March 23, 2014