Download the 2012 New Irvington Tunnel Fact Sheet

We have updated our project fact sheet as we move into Year 2 of the New Irvington Tunnel Project. The fact sheet highlights our progress during the first year of construction and provides an overview of our work in 2012.


Click here to download the 2012 New Irvington Tunnel Fact Sheet!

Boom Goes the Dynamite!

Well, technically the “Boom” is not as loud as one would imagine. The Calaveras Dam Replacement Project has begun controlled detonation activity to produce the hard rock required for construction of the dam. Due to the existing conditions of the rock, we must use controlled detonation to break down the surface. Prior to each blast, numerous steps are taken for safety and extensive watering of the blast area is done to ensure dust emissions are kept to a minimum. Pre-construction surveys are also performed prior to each blast for removal of any special species.

For the first initial blast, it took four days to drill 76 holes to place the explosives. Over 10 tons of explosives were used, blasting a total of 16,000 cubic yards of material, to be used for dam construction.

Controlled detonations only occur at the Calaveras Dam project site within SFPUC property. Detonations will continue intermittently through the end of the project in early 2015, only during daytime hours, Monday through Friday.

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

Spring Forward, Fall Back

With Daylight Savings around the corner don’t forget to change your clocks before you go to sleep on Saturday March 10. The phrase “Spring forward, fall back” is good way to remember which way to set the time.


Miners at the New Irvington Tunnel Project have taken this phrase to heart- at least the Spring forward part. As shown in the above chart, work crews broke or tied the previous daily project record of tunneling, 70 feet, with 70, 87 and 98 foot days! Miners have been averaging 45 feet of excavation per day but ideal ground conditions allowed crews to advance rapidly. All told 378 feet was excavated for the week recently also shattering the previous weekly record of 253 feet.

Some say the extra sunlight gained from Daylight Savings increases worker production. Underground, the sun isn’t a factor but that doesn’t mean the miners can’t join in on the fun!

Lasers: Inline and On-Target

“Record Day of Tunneling: DS- Laser Road Header Blasts through Miles of Rock!”

This is what a headline could say in the year 2082 during the construction of the New New Irvington Tunnel. Today, lasers serve a much different but very important purpose of keeping tunnel excavation inline and on-target.


The alignment of the New Irvington Tunnel stretches 3.5 miles from the Sunol Valley to Fremont. At depths of up to 700 feet below ground surface, crews are working in four headings to excavate the new tunnel. With miners deep underground tunneling in four different directions, how do they make sure the tunnels line up? How do they keep from tunneling into Livermore or Union City? The answer: Lasers.


Inside of each tunnel heading laser beams cut through low light conditions and provide alignment control. The lasers are mounted on the left and right side of the tunnel near the tunnel entry and project their beams on the rock face that is being excavated. Crews operating the road headers keep the machine between these beams to stay on target. Surveyors are brought in between each tunnel set (typically four feet of tunneling) to verify that the alignment of the tunnel is accurate.

Laser Road Headers and Lightsabres may never become more than the wishful thinking of science fiction enthusiasts. But for miners and the 2.5 million people that depend on a safe and secure Hetchy Hetchy Water System lasers keep the New Irvington Tunnel on-target!

Then and Now

The existing Irvington Tunnel was built in the early 20th century and can no longer be taken out of service for repairs or maintenance without impacting the water supply to customers. The New Irvington Tunnel is designed to provide a seismically-strengthened or reinforced connection between water supplies from the Alameda Watershed to Bay Area customers

Here’s a quick look at tunnel construction then and now:

Miracle Mile

Miracle Mile is a slight exaggeration but the New Irvington Tunnel Project surpassed the one mile mark last week with help of two record setting days of tunneling. Miners typically average 22.5 feet of excavation per day but ideal ground conditions allowed crews to tunnel a daily project record of 70 feet. Two days later miners set a new record and grinded out 83 feet on their way past this significant mile-stone!.

The new 18,600-foot (3.5 miles) tunnel is currently being excavated from three headings using road headers (tracked tunneling machines) and controlled detonations when necessary. Tunneling is estimated for completion in late-2013 with project completion in late-2014.

Check out www.sfwater.org/nit for weekly updates of tunnel progress.

Groundwater Monitoring Program Update

The New Irvington Tunnel project team is currently monitoring some local groundwater decline. So far, four properties south of the Sheridan Valley project area have been affected. It appears that these declines are related to tunnel construction and dewatering activities. We have initiated mitigation measures at each property and we are maintaining their water supply.

Our commitment to protecting the groundwater in Sheridan Valley has not changed. If tunnel construction causes a decline in groundwater levels that affect an individual’s property, we will initiate the contingency measures defined in each site-specific Groundwater Management Plan. The project team continues to keep a close eye on groundwater levels and will take appropriate actions to maintain water supply.

If you notice any change in your water system, please contact the SFPUC’s 24-hour Answer Line (866.973.1476). Contacting the answer line will ensure the appropriate team members respond to you in a timely manner.

Should you have any questions or concerns, we will host question and answer coffee sessions next week:

Thursday February 9
4:00 PM to 6:00 PM
Sunol Jazz Café
11986 Main Street
Sunol, CA

Friday February 10
7:00 AM to 9:00 AM
Sunol Railroad Café
11882 Main Street
Sunol, CA

If you cannot attend either of those sessions, please contact Francis Zamora at 925.232.4059 or fzamora@sfwater.org. We are always available to answer questions and address your concerns.