New Irvington Tunnel

Project Details

TUTOR PERINI AFFILIATES

Tutor Perini Civil
Contractor
Contract Amount: $268 Million

OWNER
San Francisco Public Utility Commission

LOCATION
Fremont, CA

SIZE
3.5 Miles

COMPLETION
2015

Project Description

New 3.5-mile-long, 18-foot diameter water transmission tunnel parallel to the existing Hetch-Hetchy Aqueduct in Fremont, CA. The new tunnel provides a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems.

Construction excavation occurred between 30 and 700 feet underground, utilizing conventional mining methods including mechanical, or road-header excavation, and controlled detonation where needed for hard rock removal. Extensive dewatering and tunnel reinforcement were used for groundwater inflows and unstable ground along the tunnel alignment.