McNary Dam Juvenile Bypass System (JBS) Outfall Relocation

Prime Contractor: Advanced American Construction
Owner: US Army Corps of Engineers

Umatilla, OR
October 2011 - April 2012
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Project Details

The McNary Dam Juvenile Bypass System Outfall Pipe Relocation was a fast paced project to remove and replace an existing juvenile bypass system outfall pipe. The project included the installation of 3,000 feet of new outfall pipeline, with 1,200 feet placed in the Columbia River.

The outfall portion of the project included the installation of 24 total steel cased drill shafts placed in the river. AAC constructed a special barge to facilitate the over water drilling. Special anchoring devices were developed to hold both the barge and drilling casing in place against the fast moving current. The 48-inch diameter shafts had an additional 60-inch diameter cap pour to support the pipe saddles.

The upland work included 900 feet of 42-inch buried HDPE pipe that spanned between the steel pipe to the 36-inch u-shaped corrugated metal flume section. Work to the existing fish facility included an 18-inch secondary bypass line, 30-inch raceway drain pipe addition and demolition of the existing 36-inch CMP outfall.

Project Highlights

  • Installed 3,000 feet of 36-inch steel outfall pipe, 1,200 feet over water
  • Installed 22 each, 48-inch diameter and 2 each, 60-inch diameter steel cased drilled shafts with 550 cubic yards of concrete
  • Installed 895 feet of 36-inch corrugated metal flume with walkway, supported on steel bents
  • Installed bird deterrent sprinkler system
  • Mechanical and electrical upgrades at existing Juvenile Fish Facility
  • Landscaping and site restoration

Project Photos


  • 2013 Awards

    • Award
      AGC/ALLIANT 2013 Build America Award
      AGC/ALLIANT 2013 Build America Award
      Advanced American Construction's  McNary JBS Outfall Pipe Relocation project won the AGC Alliant Build America Award in the Federal & Heavy renovation category. The Alliant Build America awards recognize AGC member companies who build the country's most impressive construction  projects in transportation, utility infrastructure and federal and heavy divisions. 

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