The New Irvington Tunnel will be constructed just south of the existing Irvington tunnel, which was built between 1928 and 1930. The existing tunnel is an important part of the San Francisco Public Utilities Commission (SFPUC) water transmission system, conveying water from the Hetch Hetchy supply and the Sunol Valley Water Treatment Plant to the Bay Division Pipelines in Fremont. It cannot be taken out of service for repairs or maintenance without impacting the water supply of customers.
The new tunnel will parallel the old, and will be approximately 3.5 mi long, with a horseshoe shape and excavated dimensions of approximately 12 ft by 14 ft. Final finished inner diameter will be 8.5 ft. The tunnel will be excavated using roadheader and drill-and-blast methods. Security-related site improvements will be built at the Irvington and Alameda West Portal facilities.
HMM is the lead consultant construction manager for the construction management team, responsible for: