Skip to main content
Close
Search Plan Room Federal Small Business
Menu

Mud Mountain Dam 9-Foot Tunnel Rearmoring

Location

Enumclaw, WA

Value

$9 M

Delivery Method

  • Design-Build

Client Type

Federal

Project 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 FT, 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 FT 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.