Project–At–A–Glance

WSIP Region
Sunol Valley

Location
Sunol Valley, Alameda County

Construction Start
November 2009

Construction Finish
June 2013

Current Status
Design, Environmental

Project Cost
$343M

The existing Irvington Tunnel is an important part of the SFPUC water transmission system, conveying water from the Hetch Hetchy supply and the Sunol Valley Water Treatment Plant in the Sunol Valley to the Bay Division Pipelines in Fremont.  Built between 1928 and 1930, the Irvington Tunnel has served a steadily increasing number of Bay Area residents to the point where the tunnel cannot be taken out of service for repairs or maintenance without impacting the water supply of customers in the East Bay, South Bay, and Peninsula regions.

In order to ensure a reliable flow of drinking water for our customers, the SFPUC proposes to construct a second Irvington Tunnel parallel to the existing one so the existing tunnel can be taken out of service for maintenance and repair. The new tunnel would also improve the reliability of the water system in case of an earthquake as it would be constructed using modern seismic design techniques.

Description
The proposed New Irvington Tunnel would be located just to the south of the existing tunnel. It would be approximately 3.5 miles (18,300 feet) long and have a horseshoe shape with excavated dimensions of approximately 12 feet by 14 feet. The final finished inner diameter would be about 8 ½ feet.

Major elements of the proposed project include:

• The tunnel likely will be excavated using conventional mining methods, such as using a “road-header” and /or “drill-and-blast.”  A portion of the tunnel might also be excavated using a tunnel boring machine. 
•  The project team plans to deposit the spoils from the tunnel excavation on SFPUC property along Calaveras Road in the Sunol Valley in an inactive quarry pit near the intersection of Calaveras Road and Interstate 680.Deposit of the spoils is planned to create a visual barrier to new quarry operation..
• A short, starter tunnel will also be mined from the Irvington Portal in Fremont. Spoils from this operation will be placed locally so that there will be no materials hauled off-site.
• At the Irvington Portal, the tunnel will be connected to Bay Division Pipeline (BDPL) Nos. 1, 2, 3, 4 and the proposed BDPL No. 5.
• To analyze and minimize the project’s possible impacts to groundwater, the project team has launched a groundwater monitoring program to track baseline groundwater levels in wells, springs, and creeks, wetlands in the area before, during, and after construction. 
• At both the existing Irvington and Alameda West Portal facilities, other security-related site improvements would be constructed.

Note: Schedule and cost information shown may vary from the 2007 Approved WSIP Schedule and Budget. The information shown reflects the current forecast information published in the latest WSIP Quarterly Report.