Bay Tunnel Project



Project Duration


Services Provided

Construction Management

Project Controls, Scheduling

QA Inspections

Environmental Compliance Reporting


The new Bay Tunnel links the existing segments of BDPL Nos. 1 and 2 and 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 1920s and 30s, lay along the bay floor and on trestles that cross over environmentally sensitive marshland. The pipe and the trestle are in a deteriorated condition. The Bay Tunnel bypasses these environmentally sensitive wetlands. The 5-mile-long tunnel bored under San Francisco Bay at depths of up to 100 feet and it was constructed using a specialized Earth Pressure Balance Tunnel Boring Machine. The excavated diameter was 15 feet with a final tunnel lining of a 9-foot diameter welded steel pipeline. At each end, there was a vertical shaft, and it connected the BDPL Nos. 1, 2, and 5 piping manifolds. The spoils resulting from excavation during this project 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 abandoned in place.