By Ashley Karen
On Oct. 13, SFPUC (The San Francisco Public Utilities Commission) awarded HH-1000R (the Mountain Tunnel Improvements project) to Michels Tunneling for $138,965,566. NTP is expected for Jan. 4, 2021.
Due to the implementation and development of new COVID-19 related construction safety laws, the bid award was delayed through the summer months of 2020.
The project includes 11 miles of rehabilitation of the 10-ft diameter, concrete-lined, horseshoe tunnel, which was finished in 1925. Work comprises contact grouting, concrete lining repairs, large control valve installations, downstream valve control structure, adit/portal improvements, new tunnel adit, water cut-off grouting, tunnel siphon extension, access roadway improvements, temporary staging area excavations and grading, water discharge treatment, the construction of a new 1,075-ft Adit Tunnel at Priest Reservoir to modify maintenance access, and environmental mitigations.
Mainly, the work will be 1,000 ft underground surface and is going to be accessed through the downstream Priest Portal, and Adits 5/6 and 8/9 at intermediate locations along the alignment. Moreover, the access will be available 7 miles upstream through the 13.5-ft diameter unlined section of the tunnel from Early Intake. McMillen Jacobs Associates (MJA) is the project designer with AECOM as environmental consultant.
