108″ ID Tunnel bypass to a Flow Control Vault (130 ft deep in solid granite) using 2 each 108″ x 72″ bifurcation wyes with 2-1/4″ reinforcing crotch plates through dual 72″ ID Flow control valves and returning to the existing Mountain Tunnel. The 400 plus feet of 108″ tunnel liner was furnished with 4″ diameter grout ports evenly spaced to aid in tunnel placement. All of the piping was delivered with AWWA C210 epoxy lining.

Award Name

Pipe Fabrication

Award Year


Product Details

  • Mountain Tunnel Improvements - Project HH-1000
  • Hetch Hetchy Water Division, San Francisco PUC
  • Sonora, CA

Date Completed

December 1, 2022


108 / 72"

Steel Tonnage Used


Steel Thickness


Steel Fitting Type

Lateral Wyes (2) Each