Construction Advisory: New Irvington Tunnel Irvington Portal

We wanted to inform you of some very important construction activity affecting the neighborhood at the Irvington Portal site off Mission Boulevard. 

Irvington Portal work August 27 – September 15: 
As part of the process of preparing the tunnel to be brought into service, we will need to provide additional tunnel ventilation to our construction crews at the Irvington Portal site. The equipment will begin mobilizing in the area on August 27, 2014, and work should be complete by September 15, 2014. The ventilation equipment, which includes a fan and generator, will operate 24 hours a day. Cooling air is needed for crews who are lining the tunnel with a cement mortar to prepare it for being put into service. The sound barrier walls will keep the noise to a minimum and the contractor will install additional noise reduction measures.

Disinfection Process starting October 2014: 
Starting the first week of October, we will begin the disinfection process to bring the New Irvington Tunnel into service. In order to disinfect the tunnel, crews will need to stage generators and lights for the 24 hour a day filling/disinfection. The set up will occur during day light hours. The filling/disinfection process will take 2-4 days to complete once it begins. The expected night time activities should be limited to three nights.

What Happens Next?
The New Irvington Tunnel is anticipated to be in service delivering water sometime in November. The above ground work and restoration will continue into early 2015. These include final installations and burial of the new portal facilities, construction of a new security bunker at the existing tunnel portal (on top of the hill), and site restoration work, planting and fencing. The remaining sound walls will be removed after the entire site is restored.

Project Background
The New Irvington Tunnel Project is part of the $4.6 billion Water System Improvement Program (WSIP) to repair, replace, and upgrade our system’s aging pipelines, tunnels, and dams. The new 3.5 mile long tunnel will provide a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems. Final construction is expected to be complete in 2015. 

Questions / Concerns?
We greatly appreciate your patience. Please call our 24-Hour Answer Line at 866-973-1476 or email mle@sfwater.org or blauppe@sfwater.org if you have any questions.
Follow us online at sfwater.org/sunolvalley

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Update: New Irvington Tunnel Construction Activity at Irvington Portal

Excavation of the New Irvington Tunnel is more than two-thirds complete! The contractor has finished making the last of the necessary connections between the large water pipelines at the Irvington Portal. The contractor will begin ramping down construction activities at a portion of the site. The first step will be the partial demobilization and site restoration on the southern portion of the property.

Starting as early as February 20, 2013, the contractor will begin the process of removing some of the sound barriers at the project site. (See Map Below)

What to Expect
The sound barriers will be removed at the locations depicted in the map. The work involves removal of the panels and digging around the concrete foundation. Workers then remove the foundation and cut or pull the steel beams out. The excavated area would then be backfilled. Noise associated with sound barrier removal will include the operation of heavy equipment, back up alarms and concrete breakup.

Removal Hours
Sound barrier removal can take place Monday through Friday from 7:00 AM to 7:00 PM. We will continue to monitor noise and vibration in this area to ensure full compliance with strict noise and vibration standards set forth in the project’s Environmental Impact Report.

What’s Next?
We are not done at Irvington Portal, yet! Installation and burial of permanent portal facilities and security improvements will continue through 2013 into 2014. Site restoration for the remainder of the project site will commence in 2014.

Questions? 24-Hour Answer Line at 866-973-1476 or email mle@sfwater.org or blauppe@sfwater.org

Areas in yellow highlight sound barriers to be removed,
areas in blue will still remain

 Photo of Sound Barriers



A Road Header Rendezvous

9:46 AM June 12, 2012

Inside of a 13-foot diameter hole carved into the Alameda foothills, crews waited yesterday morning staring at an imposing rock wall.  A moment later, as if it came from within the mountain, a spinning titanium studded knuckle broke through. It moved back and forth and up and down until the wall disappeared.  What happened next was a long time coming: two crews, dressed in identical hard hats, headlamps and goggles stepped through the new hole, shook hands and then shared a laugh.

Video Captured with Permissible Camera

After 13 months of digging the New Irvington Tunnel from four separate tunnel headings, miners from two of the headings met up with each other underground today. Called a ‘hole-through’ in tunneling terminology, the road header teams from the Irvington Portal in Fremont and the Vargas Shaft 4,500 feet away shook hands somewhere under the mountainside and formally completed this section of tunnel excavation.

The road header holes-through the rock face

Miners at the Irvington Portal watch the road header hole-through from the Vargas Heading 

Miners celebrate their achievement

Photographs by R. Scheswohl ©2012 SFPUC, All Rights Reserved

The tunnel is excavated using conventional mining methods including a road header (a tracked tunneling machine) and, in sections of hard rock, controlled detonations.  In May 2011, a 55-ton road header was lowered down the 115-foot Vargas Shaft and began to grind its way west.  A month later, miners at the Irvington Portal in Fremont began tunneling east and set the two crews on a collision course.  

Following today’s hole-through, miners will prepare the tunnel for the installation of 102-inch diameter steel pipe.  The pipe, manufactured in California, is installed in 50-foot sections and welded together inside of the tunnel.   The much longer 14,400-foot Alameda West-Vargas tunnel segment is currently being excavated and is expected to hole through in fall 2013.  Construction of the entire project is scheduled for completion in fall 2014.