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BDPL Reliability Upgrade - Tunnel (WSIP)

Project Update
Pipe Installation Complete for 5-mile-long Bay Tunnel Project

All the pipe installation work for the Bay Tunnel Project is now complete. In October, the contractor finished placing 654 40-foot-long pipe spools to form the steel pipe inside the new 5-mile-long tunnel under the Bay. Crews are now working to further secure the pipe lining using “foam” concrete. This will also protect it from earthquake damage and corrosion. Once this work has been completed, the new pipeline will be lined and cleaned in order to be disinfected.

The next step is to install the vertical pipe spools at each shaft, hydro test and disinfect the entire Bay Tunnel Pipeline System to prepare to refill it with Hetch Hetchy water. Also a new building to house the controls for the new pipeline is under construction. The Bay Tunnel Project has been in construction for three years, and it is expected to be completed nearly 7 months ahead of schedule in late 2014.

Last pipe spool being placed inside the Bay Tunnel.
Each 40-foot-long pipe spool was welded immediately after being placed in the Bay Tunnel.


Bay Tunnel Pipe Installation


Project Description
The new Bay Tunnel will link the existing segments of BDPL Nos. 1 and 2and the future BDPL No. 5 in the East Bay with those on the Peninsula. The existing portions of BDPL Nos. 1 and 2, which were built in the 1920’s and 30’s, lay along the bay floor and on trestles that cross over environmentally sensitive marsh land. The pipe and the trestle are in a deteriorated condition. The Bay Tunnel will bypass these environmentally sensitive wetlands.

The tunnel will extend 5 miles under San Francisco Bay at depths of up to 100 feet and it will be constructed using a specialized Earth Pressure Balance Tunnel Boring Machine.  The excavated diameter will be 15-foot with a final tunnel lining of 9-foot diameter welded steel pipeline. At each end there will be a vertical shaft, and it will connect the BDPL Nos. 1, 2, and 5 piping manifold. The spoils resulting from excavation during this project are anticipated to be used as part of the South Bay Salt Pond Restoration Project, conversion of adjacent salt ponds to marshland. The portion of the existing BDPL Nos. 1 and 2 that are replaced by the tunnel will be capped on each end and will be abandoned in place.

Project Information

    April 2010
    June 2015
  • COST
    $286 Million

Additional Information

The information shown reflects the current forecast information published in the latest WSIP Quarterly Report.

Work Hours

Normal work hours are 7 a.m. to 6 p.m. When tunneling begins, underground work will be 24-hours a day due to project demands. Work will be monitored closely to ensure that noise, light and other disruptions are minimized. Construction is expected to be completed in 2015.

- Bay Tunnel Fact Sheet - Summer 2013
- Bay Tunnel November 2012
- Bay Tunnel Fall 2012 Fact Sheet
- Bay Tunnel Winter 2011 Fact Sheet
- Bay Division Pipeline Reliability Upgrade - Tunnel Project Fact Sheet


Need More Information? Contact

Bay Division Region Hotline
Phone: (800) 571.6610 or