Lower Granite Dam

Talisman was contracted to perform the saw cutting and demolition work associated with the modifications and extension of the existing juvenile fish passage inside of Lower Granite Dam.  The work involved multiple phases and mobilizations and included the installation of temporary work platforms at the drainage gallery shaft and at the South Non-Overflow area.  Talisman tunneled through portions of the concrete dam for the purpose of connecting the existing fish passage to the new collector.  After completion of the new tunnel section, Talisman performed the wire sawing, core drilling and demolition work associated with the expansion of the existing fish passage.  Equipment, materials and debris had to be inserted and removed through an opening in the downstream wall of the drainage gallery.  The scope of work included concrete wire sawing, demolition and waste load out from limited access areas inside the main dam structure.  Talisman removed approximately 1,100 cubic yards of concrete from the existing 600’ fish passage and approximately 400 cubic yards of concrete from a new 140’ fish passage that was drilled/cut through the dam.