The New Irvington Tunnel is officially in service!

Our teams are excited to announce that the New Irvington Tunnel is officially in service carrying drinking water to our 2.6 million Bay Area customers.

This is a major milestone since the completion of the New Irvington Tunnel Project completes the last three tunnels in the Water System Improvement Program (WSIP), creating a critical water lifeline able to withstand earthquakes on the Hayward, Calaveras, and San Andreas faults.

Located between the Sunol Valley and Fremont, the new seismically-designed tunnel is the last of three tunnels making up this “water lifeline” around the Bay.  The project is part of the agency’s $4.8 billion Water System Improvement Program.

The tunnel was constructed by the joint venture of Southland Tutor Perini who began tunneling in March 2011. It was constructed using conventional mining techniques from four separate headings using road headers and controlled detonation to break up the hard rock.

Tunnel Facts:

• Tunnel Length: 18,660 feet or 3.5 miles
• Location: Parallel to the existing tunnel between Sunol Valley and the City of Fremont 
• Depth: Between 30 feet and 700 feet underground
• Finished internal diameter: 8.5 feet
• More than 7.8 million pounds injected into the tunnel
• The New Irvington Tunnel will carry approximately 120 million gallons of water a day on average during normal operating conditions when both tunnels are in service.
• The maximum amount of water the tunnel can transport per day: approximately 300 million gallons 
• This project provided approximately 42% of total labor hours to SFPUC service territory residents, and nearly half (48%) of total apprentice hours to SFPUC service territory apprentices ensuring our local workers and local residents were able to participate in this unique, once-in-a-lifetime construction opportunity.

What Happens Next?

Now that the tunnel is in service, the construction team will begin restoration of the above ground facilities. The SFPUC will take the existing tunnel out of service for inspection in early March 2015. The entire New Irvington Tunnel Project will be complete in Fall 2015.

1933: Historic photo of  worker at Irvington Portal spherical manifold

Today: New Irvington Tunnel worker at new dishhead at Irvington Portal

Last of the Pipe Installed at New Irvington Tunnel

The crews have reached a major milestone and installed the last of the pipe for the New Irvington Tunnel.  A 35 ft section of steel pipe was prepped and mortar lined at the surface before being lowered into the Vargas Shaft. This officially completes the entire 3.5 mile water transmission tunnel.  Final steps are being made the next week to disinfect the tunnel and bring it into service to provide a seismically designed connection to provide water to our 2.6 million Bay Area customers. 

The Final Stretch: Mortar Lining completed for the New Irvington Tunnel

This week the construction crews completed the final stages of mortar lining in the tunnel. Mortar lining is one of the final stages of constructing a water tunnel before we bring it into service.  

Our workers used specialized equipment that sprays cement on the pipe’s interior to prevent corrosion of the steel pipe and prepare it for water conveyance. This completes a major milestone for the tunnel. The tunnel is anticipated to be in service by the end of this month and will soon deliver water to our 2.6 million customers. We are definitely getting excited for the final stretch!

The Last Butterfly Valve for New Irvington Tunnel

You know you’re making progress on construction when you start celebrating your ‘lasts.’ Last excavation to be completed. Check!  Last steel liner inserted into the tunnel. Check! Now we have another: the last valve to be installed underground.

And not just ANY valve. This is a valve that is 8 feet in diameter that will eventually divert water from the existing piping connections into the New Irvington Tunnel.  This Butterfly Valve regulates flow within the pipe with a rotating a disc within the pipe. When closed, the disc, or butterfly, completely blocks flow.  When open , as seen in this sample of a butterfly valve from a dam in Japan, the disc rotates one quarter to allow flow to pass by.

And operating this valve is no easy task. If you were to manually crank it closed (or ‘actuate it’, as our operators say), you’d need a whopping 400 revolutions.  Our operators use electric actuators for this very reason, and will be able to operate this valve remotely.

We hope to actuate this valve to bring the New Irvington Tunnel into service this Fall!

New Irvington Team installs final valve

Sample Butterfly Valve
Photo courtesy of Wikimedia Commons

Lined, Then Sealed, Then Delivered This Fall. The New Irvington Tunnel Reaches Another Milestone

Imagine an 8.5 foot in diameter steel pipe roughly the length of a tractor trailer. Now imagine gently placing it into a 14-foot tube the length of 1½ Golden Gate Bridges? Now weld each of them together from the inside of the installed pipe in less than two months.

Well, that is EXACTLY what we did. This week the New Irvington Tunnel contractor completed the installation of a total of 14,600 feet (2.7 miles) of the welded steel liner into the tunnel. The 50 foot segments were all installed from the Sunol Valley and transported with a customized pipe placer westward into the tunnel. This completes the steel lining for the entire 18,660 foot (3.5 miles) New Irvington Tunnel.

What’s next? More grouting! Our teams will mobilize in March to prepare the tunnel to place cellular grout into the space between the steel liner and the excavated tunnel. This will effectively backfill the space between the tunnel pipe and tunnel wall, sealing it off to prevent water from seeping into or out of the tunnel.

We plan to bring the New Irvington Tunnel into service this fall, when drinking water will officially be transmitted through the new tunnel. Final project completion of the New Irvington Tunnel Project – including above ground restoration - is expected in mid-2015.

The New Irvington Tunnel will provide a seismically designed connection for water supply for 2.6 million bay area customers. 

50 ft segments of steel liner being delivered
Photo credit: Robin Scheswohl

View of steel liner from inside of Alameda West Portal
Photo credit: Robin Scheswohl

Welding work taking place on steel liners
Photo credit: Robin Scheswohl

Another Shut Down for the Books

The New Irvington Tunnel Project has just completed its winter pipeline shutdown work this season.

“What’s the big deal?” you ask. Here’s why.

Our construction team must construct upgrades to this water system while it still provides water to our 2.6 million customers.  We shut down the pipelines in order to cut into them and weld pipeline connections to improve your water system.  We can only do this for short periods of time during winter months when demand for water is low. The timelines within which the contractor can complete their work are very short. The work is very complex and challenging in a very tight area. No pressure!

At the Irvington Portal area in Fremont, the contractor Southland Tutor Perini had two shutdown seasons – last year and this – to complete a complex set of pipeline connections between the existing Irvington Tunnel, the New Irvington Tunnel currently under construction, and the five Bay Division Pipelines. These pipelines can only be shut down one at a time during winter months.

The SFPUC is creating pipeline connections to allow water to be distributed from both tunnels to all five pipelines in a variety of ways.  Work on the final Bay Division Pipeline #4 connection started on November 5, 2012, and the project team recently completed the work.

For our customers this means a water transmission system that will be more flexible from an operational standpoint and better able to withstand a major earthquake.  For our construction team it means a pat on the back for a job well done.

Work being done on the final Bay Division Pipeline #4 Connection

Workers perform welding work on pipeline

For more project info, please email mle@sfwater.org or call our 24 hour answer line at 866-973-1476.

A Different Kind of Tailgate Party

Early Monday morning the men and women responsible for building the New Irvington Tunnel have one thing in mind: SAFETY. Why? Because construction can be a dangerous profession and working underground adds to the risk. This is why safety is paramount for the San Francisco Public Utilities Commission (SFPUC), the Water System Improvement Program (WSIP) and Southland/Tutor Perini Joint Venture (STP).


Safety is important every day, however, Tailgate Meetings kick off every work week for all construction personnel working onsite. It gives safety managers and construction superintendents the opportunity to reinforce safe work practices. For example, when discussing fall protection, presenters demonstrate the proper use of personal protective equipment. Workers are also reminded to strap in when they are elevated over six feet. The presentations are designed so workers think safety before, during and after any activity. Other safety topics include first aid, emergency tunnel rescue and chemical handling.

Tailgate Meetings are just one tool (incidentally they are also called Toolbox Meetings) used to promote STP’s proactive safety culture. Signs posted through out the site are another way of encouraging workers to think and practice safety. Future blog posts will go into more detail about a number of safety related topics such as emergency tunnel rescue and gas testing and training.