The new 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.
 

Ed Harrington, general manager of the San Francisco Public Utilities Commission said: “The New Irvington Tunnel project is among the most important components of the entire system to ensure that our 2.5 million customers will have water after a major earthquake. For this particular project to move forward is a significant moment for the water system and our customers.”
 

The seismic water tunnel will be excavated using conventional mining methods, including a road header and controlled detonations. The finished horseshoe shaped tunnel will have an internal diameter of approximately 8.5 to 10.5 feet and is estimated to cost $250m.
 

The San Francisco Public Utilities Commission expects to advertise the project for bid on November 17, 2009 and select a contractor by early January. Construction is scheduled to begin in April 2010 with completion in early 2014.