The 3.5 mile (5.6km) New Irvington Tunnel will transmit water between the Sunol Valley and Fremont to 2.6 million residents.

Following the hole-through Miners will now prepare the new tunnel for installation of 8.5ft (2.6m) diameter steel pipe, installed in 50ft (15m) sections and welded together inside of the tunnel. The alignment is between 30ft (9.1m) and 700ft (213.3m) underground and crosses seven fault zones.

Tunneling started in 2011 with crews advancing from two portals and at the midway Vargas Shaft mining in both directions.

Hatch Mott MacDonald is the construction manager and URS and Jacobs Associates are the project designer. Final completion of the project is scheduled for mid-2015