The purpose of this project is to replace two existing culverts with fish passage culvert tunnels. Drill Tech utilized various ground support methods, including pre-excavation support ahead of mining to ensure stability through the alluvium type soils encountered. The final tunnel condition included a partial liner of reinforced shotcrete as scour protection for stream flow. A unique challenge of the site conditions included the active rail line that traversed above the excavation and seasonal work schedules to accommodate seasonal fish migration. All in-stream work took place from July 15th to October 31st. The work was scheduled over two seasons, with one tunnel to be completed each year, but both tunnels were completed in year one.
Contract Value:
$6.6M
Delivery Method:
Design Build
Property Owner:
NAVFAC Northwest
General Contractor:
Advanced Technology Construction