Mud Mountain Dam 9-Foot Tunnel Rearmoring
Location
Enumclaw, WAValue
$9 MDelivery Method
- Design-Build
Client Type
FederalProject Type
- Pipeline (Penstock)
3,000,000 lbs. of granite used
Bedload travel of 74 feet per second
Natural granite block used as armoring surface–only used in this capacity in one other place in the world
The US Army Corps of Engineers, Seattle District selected Garney to design and construct the rearmoring of a 9-foot, damaged steel-lined tunnel designed to clear bedload and sediment from the bottom of the Mud Mountain Dam in Enumclaw, WA. Garney’s proposed alternative approach extends the life of the 1,800-foot tunnel from 10 to approximately 40 years. Garney proposed a Value Engineering Cost Proposal post award to reline the bottom of the tunnel with granite making it the first project of its kind in North and South America.
AWARD
DBIA National Award of Excellence, 2019 DBIA
ENR Northwest Specialty Construction Best Project, 2020 ENR Northwest
