The Corps of Engineers awarded a $45.4 million contract to General Construction Co. to build a spill wall in a stilling basin at 1,779.8-MW The Dalles Dam, on the Columbia River in Washington.
General Construction, Poulsbo, Wash., responded to a solicitation that estimated the work would cost from $25 million to $100 million. (HNN 5/27/08)
The Corps’ Portland District said work would involve construction of a spill wall to aid fish passage in the stilling basin below the dam between Bays 8 and 9. The wall is to be built of pre-cast and cast-in-place concrete, ten feet wide, about 830 feet long, and 25 to 43 feet tall.
Work will involve fabrication, transportation, and setting of large pre-cast concrete cells, concrete demolition, anchor installation, and grouting, rock removal, underwater and above-water concrete placement, rock drilling, and installation, grouting, and tensioning of rock tendons.
Spill to pass juvenile fish downstream will take place between two in-water work periods. Therefore, the Corps expects construction will extend over two seasons. The agency issued a notice to proceed to the contractor in August. The work is scheduled for completion by March 20, 2010.