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

A Tale of Two Geary Road Bridges

It has been more than 80 years since the original Geary Road Bridge was built over Alameda Creek, connecting park users and lease holders to Sunol Ohlone Wilderness Park trails in the East Bay Regional Park District.  Over time the first Geary Road Bridge was unable to support the weight of large vehicles, forcing trucks to drive through Alameda Creek at that location. So, the San Francisco Public Utilities Commission constructed a new bridge that recently opened to the public. The new Geary Road Bridge is highway grade, which protects Alameda Creek by eliminating the need for large vehicles to drive through the creek. 

The amazing contrast of the old and new bridge is depicted in the photo above that was composed of two photos shared with us on Twitter by @RHMImages, a landscape and rust photographer.  Thanks @RHMImages for the fabulous photos!

Whales in the Sunol Valley?

Since construction began at the Calaveras Dam, team paleontologists have had some remarkable finds from ancient shark teeth to marine mammal vertebrae all collected during the excavation of over 4 million cubic yards of earth over the sediments that were once an ancient sea floor.  

Just this week, project paleontologists found a portion of an ancient whale skull in the slope above the spillway excavation of the new dam. The skull is almost a yard long and relatively intact, except for a small portion of the right rear section which is missing. Our paleontologists are still researching the find but initially assess the fossil to belong to a Mysticete (or baleen) whale, from the family of Humpback, Grey or Blue whales that live in the oceans today and forage on plankton. This fossil was discovered in the temblor sandstone formation which makes it over 20 million years old.

The project takes important steps to salvage these paleontological finds for educational purposes. The critical construction work to build a replacement dam has not been affected and continues, while we discover amazing fossils to add to the rich history of this valley.

Paleontologists Bruce Hanson and Jim Walker work on uncovering fossils at Calaveras Dam. Photo credit: Robin Scheswohl

In November 2013, a collection of bones including vertebra from a marine mammal were discovered on the lower portion of the Spillway.  It appears to show a complete cross section of the body, neural arch and measures 15 x 7 centimeters. Some of the other bones appear to be ribs. None of the specimens found interfered with construction activities and the specimen still remains in the rock.

Pipe Installation for Backup Pipeline Approaches Finish Line

Sprinting to completion, crews have been working hard to install the pipe for the new 1.3 mile-long San Antonio Backup Pipeline, and it is paying off - they are almost done!! To date, about 85 percent of the 5.5-foot-diameter pipe has been installed in the ground for the new water pipeline. With the bulk of the pipeline installation behind them, crews have begun construction of some of the small above-ground structures and the discharge pumps at the quarry storage pond at the north end of the site. Once they cross the finish line in 2015, the San Antonio Backup Pipeline will add operational flexibility to our Sunol Valley water transmission system that currently serves 2.6 million customers.

The first 50- feet-long pipe segment was delivered in August 2013. 

 Crews prepare to set the pipe in the trench.  

Once installed, the pipe segments are welded together to secure them in place.

The New Geary Road Bridge to Open on Feb. 7

We are excited to announce that the new Geary Road Bridge will be ready for use on Friday, Feb. 7th! The new 150-foot-long concrete and weathered-steel bridge has replaced an old bridge that was unable to support the weight of the large vehicles that use it regularly. It crosses Alameda Creek downstream of Calaveras and Alameda Creek Diversion Dams, and is located within the East Bay Regional Park District’s Sunol Ohlone Wilderness Park leased lands. This new bridge will protect Alameda Creek at this location by eliminating the need for large vehicles to drive through the creek’s low-water crossing. Planting and restoration of the site are underway. 

Thanks to the East Bay Regional Park District staff, park visitors, private landowners, lease holders and all members of the public in the area for their patience during construction. To see how the new Geary Road Bridge was constructed , take a few moments to check out our project video:

A Day in a Life of a Driller

A crucial job that is integral to the design and construction of the Calaveras Dam Replacement Project might surprise some: the driller. During the design phase of the project we drilled more than 11,000 linear feet of core samples to characterize the subsurface ground conditions in and around the location of the replacement dam.

And we didn’t stop there. We are still drilling on the project to clarify the geologic conditions specifically on the left abutment (or adjoining wall) of the future new dam. Skill is key in exploratory drilling. We are lucky to have incredible personnel on site. We’d like to introduce you to one now - one of our lead drillers - Bay Area resident Will Halai.  He has been performing this type of work on construction projects for more than six years.

Will immigrated to the United States in 1992 from Tonga, a country in the South Pacific, to make a better life here for his family.  He works daily with his assistant Fine Taufatofua, also of Tongan descent, who has been drilling for the last four years of his career.  Both are members of the Operating Engineers Local 3, the union which represents heavy equipment operators and construction workers.

Typically, each drill advances a bore hole 40 to 60 feet per day.  The 4-inch diameter drill holes average about 100 feet in depth, while the rock core they extract is 2.5 inches in diameter.  After the borings are drilled, many are logged with a televiewer, which provides a continuous image of the inside of the borehole to allow the identification (and orientation) of important geologic features.  On average, five to six core borings are completed per week.  All of this information helps to ensure that the new Calaveras Dam, when built, will sustain a maximum credible earthquake on the nearby Calaveras Fault.

Will works with Bill Henrich of Norcal Geophysical during televiewer logging,
which is used to obtain important data from the core boring

Union Local 3 Operating Engineers Will Halai & Fine Taufatofua
pause from drilling work at Calaveras Dam 

What’s on Tap for the Sunol Valley in 2014?

A few weeks into the New Year, our Sunol Valley Project teams are already very busy with the important work to seismically upgrade facilities which deliver drinking water to 2.6 million Bay Area customers as part of the Water System Improvement Program (WSIP) and other ongoing projects. Here’s a quick snapshot of the anticipated activities of the year to come. Please visit us often on our blog to stay up to date and learn more!

New Irvington Tunnel
In October 2013, we completed excavation of the new tunnel.  Recently, the project team began installing the inner lining for the tunnel. These are 50-foot-long, 8½ foot in diameter steel pipes that are inserted into the tunnel on a special train. Once in place, these pipe segments are welded together from the inside.  On average, seven pipe sections are installed daily.  Project completion is anticipated for 2015.

50 ft. pipe being prepared for installation at New Irvington Tunnel

Calaveras Dam Replacement Project

The largest project in the Sunol Valley continues with ongoing major excavation as well as drill and blast activities to stockpile materials in preparation for the construction of the replacement dam.  We are still clearing out loose soil and rock materials in the area to make room for the new dam. In the coming weeks, the project will begin construction of the new 1,550-foot-longspillway, all the while dealing with the continuing challenges of the site’s complex geology. Grouting work on the left abutment of the new dam will also begin soon.  As construction progresses, the environmental team continues to find and catalogue interesting fossils at the site. Projected completion is anticipated in 2017.

Aerial view of upper Left Abutment for Replacement Dam
(left side of valley when looking downstream)

San Antonio Backup Pipeline

Construction of the San Antonio Backup Pipeline, which will add operational flexibility to our Sunol Valley Water transmission system, has been moving forward towards completion in March of 2015.  The majority of the new pipeline has been installed and is in the ground.  The new slurry wall was also completed last year.  This year the project team will focus on construction of the small above-ground structures and discharge pumps at the quarry storage pond at the north end of the site.

Workers excavating and shaping the hillside in preparation
for the outfall structure that will be going into Pond F3-east

Town of Sunol Fire Suppression System Project

2014 will see the start of construction of this important public safety project in the Town of Sunol.  The SFPUC will upgrade the water distribution system for the Town of Sunol since the current system is inadequate.  The SFPUC will add additional fire hydrants in commercial and residential areas of the Town of Sunol, replace pipelines on County roads to improve the flows from the fire hydrants, and also replace two to four of the Town's existing water storage tanks on the hill.  Construction for this project is anticipated to start spring/summer of this year.

Alameda Creek Watershed Center and Sunol Yard Upgrade

Plans are underway to design and construct the Alameda Creek Watershed Center located near the Sunol Water Temple, as part of its efforts to improve the existing facilities in the Sunol Yard. The proposed Watershed Center would provide a place for people to gather and learn about the Alameda Creek Watershed, its natural resources and its role as part of the SFPUC water supply system as well as connect with the history of the Sunol Valley.  This project is in its early planning and design stages with construction anticipated to begin in 2015. 

Bioregional Habitat Restoration
Construction activities for the Bioregional Habitat Restoration (BHR) program will start winding down this year. We will, however, continue to monitor the success of these projects through 2024. The projects that are nearly completed within the Sunol Valley  -- Goldfish Pond Restoration at the southern end of Calaveras Road, San Antonio Creek Restoration, Sheep Camp Creek and Goat Rock – have restored or enhanced a combined total greater than 1,500 acres of sycamore and oak riparian woodland, oak woodland and savannah, and serpentine and annual grasslands.

This project includes restoring 5,000 feet of the existing Sheep Camp Creek.

Completed Projects

As we start 2014, we can also continue to celebrate the completion of the Sunol Valley Water Treatment Plant Expansion and Treated Water Reservoir project in September 2013. This water treatment plant now enables us to filter and provide 160 million gallons of water per day to our Bay Area customers for up to two months should our Hetch Hetchy Reservoir supplies become unavailable due to an earthquake or other emergency.

We look forward to working with you this year and all the good things to come to Sunol Valley!