Blog
January 2016

Along Spirit Lake, in Mt St Helens, Washington, The U.S. Army Corps of Engineers bored a 1.6-mile tunnel through bedrock to provide a new outlet after the 1980 eruption of Mt. St. Helens blocked the lake’s natural outlet.  Without the tunnel, the lake could fill and begin overflowing onto nearby highways.  Recently, it was discovered the floor of the tunnel has been rising effectively shrinking the diameter of the tunnel. Otak is part of the team working to fix the tunnel to keep in in operation. Our Professional Land Surveyors are establishing survey control in the Spirit Lake Tunnel and marking the locations for the work to take place using robotic total station survey equipment. This project is 6,000 feet inside the tunnel. Work in a tunnel that is always wet, with running water from 2” to 40” deep, dark, and strongly ventilated is difficult. The crew spent their days a mile and a quarter inside the 11’ diameter tunnel. The remote location is a 2 ½ hour commute from the nearest town. The crew worked Friday-Tuesday, 14 hours each day and our office technical staff worked each evening starting around 8pm when data could be sent in from the remote location. Data was processed each night so new information could be used the next day.  Construction is scheduled to be complete by May 2016. 

 

Comments

Jordan said:
January 29, 2016, 11:45 AM

Looks like the crew worked really hard! Hope things are going well and on time. Thanks for sharing!



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