Lake Cushman construction work begins Nov. 8

Condon-Johnson, the contractor Tacoma Power hired to fix problems associated with water flowing through the embankment near the Cushman Dam No. 1 spillway, will begin site work on Nov. 8.

The company will begin construction on a new core wall on Nov. 21, and expects to complete the project within 12 weeks.

The current lake level is 685 feet. It will remain at this level until mid-December, while work on the core wall and other construction projects take place.

Tacoma Power has begun work on a floating surface collection system that will attract and capture juvenile fish upstream of Cushman Dam No. 1 for transport around the dam. The work being done must take place when the lake is lowered, so Tacoma Power accelerated the process to coincide with the core wall construction project.

The U.S. Forest Service has begun repairing the Causeway Bridge on the upper end of Lake Cushman - a project that also requires a lower lake level.

Once these projects are complete, Tacoma Power will begin refilling Lake Cushman. If water conditions are favorable in the winter and spring, Tacoma Power anticipates normal lake levels through the summer of 2012.    

History

Tacoma Power became aware of a safety issue associated with the Cushman No. 1 spillway that required us to keep the water level in Lake Cushman lower than anticipated in 2011. 

We noticed an increase in the amount of water flowing through the earth embankment near the spillway of Cushman Dam No. 1. So we brought in some geo-engineering experts to help us assess the situation. The assessment concluded that we needed to avoid internal erosion damage, which meant keeping the lake level below elevation 725 feet until we repair the problem. 

Safety is Tacoma Power’s number one priority and by maintaining the reservoir at these reduced levels, we are able to mitigate the risks associated with this recent development. As a result, we do not anticipate any operational changes that would affect the property located downstream of the dam.